Sun, 03 May 2026 10:46:51 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17825 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17825 Fri, 28 Apr 2023 16:34:15 +0100 TigoDog
I'm helping my dad convert a 19th century hay barn into a 3 bed home that he'll live in. We're aiming for Band A EPC, so a very high level of insulation and air tightness, if not quite PassivHaus standard.

We effectively have a blank slate, so I'm interested in the GBF hive mind's opinion on the best heating solution. We are expecting to use an air-source heat pump, and I know the most commonly done method is an air-to-water system, heating water for UFH and general use. However, there is no existing wet heating system and I'm interested in air-to-air systems, particularly ducted systems (not wall mounted units). My thinking is that it should be more efficient to use the warm air created by the ASHP to heat the home directly, rather than losing energy in converting warm air to warm water. Also, UFH is expensive to install and ducted air should be cheaper(?). I'm also interested in how it could interact with Mechanical Ventilation. I imagine it would add complexity, but for the money I've seen quoted for UFH, I'd guess you could get a very high-end warm air/ventilation setup.

I know warm air systems were wide spread in residential buildings in the 70s - but were not popular as I understand it. They are common in commercial buildings (HVAC) and I assume they have come along way in the last 50 years, but most contractors I speak to seem to be pushing wet UFH. I'm trying to understand if this is just 'what they're used to' installing, more profitable, or if it is genuinely a better solution.

I appreciate he'd need a separate solution for hot water if we use the warm air system. He has space for solar, or if not, would an electric water heater would do the trick, or would that negate the efficiency gains? I've seen this system which does both in another thread, but according to the Daikin installer I spoke to, it isn't yet available in the UK market. https://www.daikin.eu/en_us/product-group/air-to-air-heat-pumps/multiplus.htm

My dad is relatively open to both options, but I wouldn't want to push something on him that doesn't work well, or 'feel nice'.

The barn is in the South of England (Berkshire). I include plans, which I have permission to post.

I'd welcome your opinions, or alternatively suggestions of contractors that can help.

Thanks in advance!]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17790 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17790 Tue, 21 Mar 2023 09:01:16 +0000 revor
https://bsee.co.uk/pump-industry-urges-government-clampdown-on-non-compliant-central-heating-pumps/

Rather worrying this is happening and unnoticed and reminiscent of the fake electrical cable scandal of a few years ago. These sort of imports just undermines our own manufacturers. To put on a CE marking to indicate the product meets European conformity when it actually means China Export is taking the proverbial.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17785 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17785 Sat, 18 Mar 2023 16:46:52 +0000 djh
The radiant heater is a Steibel-Eltron IW180, which looks the same as an IW120 but has three 600 W bars. SWMBO has decided that it might be nicer to have some kind of panel heater or radiator instead of it, in approximately the same place. I'm happy to go along with this (SMBO), so I'm looking for any suggestions as to which heater to pick. I don't know much about the subject. I'd like wall-mounting, or wall stabilised anyway. Radiant panel or convector? Desirably no fan or other noise. Any form of built-in storage worthwhile? Any thoughts about reliability of particular models or brands? Dust traps? Appearance? Oh and if it has any smarts, then are they accessible to third-party control systems such as Home Assistant or IFTTT etc?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17781 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17781 Thu, 16 Mar 2023 12:45:51 +0000 greenfinger
Back again with another insulation question. I've came across a couple of examples of people pushing PIR further into the void between rafters (but not so far as to impede the airgap behind for ventilation) rather than flush with the rafter face. Looking into it, I found this was done on purpose to create a gap between those between rafter pieces of insulation and the perpendicular insulation installed beneath to the underside of the rafters. These airgaps apparently create reflective radiation and increase the effectiveness.

Just wondered what people think of this principle and whether it is right or not?

And if the idea does have merit, what would the minimum amount of air gap needed be to have any worthwhile effect? Would 5mm/10mm do anything?

Many thanks]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17764 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17764 Thu, 02 Mar 2023 09:05:24 +0000 jhsigma https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17750 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17750 Wed, 22 Feb 2023 20:29:05 +0000 minisaurus
I don’t think radiator size would be an issue in most houses in most parts of the Uk, if one uses the heat pump in the way one does here in Scandinavia.

This is because the water temperature to the radiators is determined by the outdoor temperature (sensor) and the type of building (these are parameters you program into the pump).

For example, today, where I live it’s around 3+ degrees outside, the temperature the pump is sending to our radiators cycles between 35 and 45 degrees and we enjoy 20.5 degrees indoor temp (at the temp sensor). Our house is in no way super insulated.

One difference to the Uk gas boiler approach, is that the pump runs 24/7, so lower radiator temperatures work with this approach.

Our pump is EAHP, and with outdoor temperatures around 0 degrees and higher, the electric “booster” element hardly ever runs for space heating.

So, I reckon, with the relatively high winter temperatures in the Uk, and the correct configuration, you could run an ASHP economically without changing the radiators.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16867 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16867 Fri, 01 Jan 2021 19:04:38 +0000 Ed Davies
https://www.theguardian.com/environment/2021/jan/01/avoid-using-wood-burning-stoves-if-possible-warn-health-experts

“Campaigners and health experts are calling on people who have alternative heating not to use their wood burning stoves this winter amid growing concern about their impact on public health.

[…]

Now experts at the Asthma UK and British Lung Foundation Partnership are asking people with wood burners only to use them if they have no alternative source of heat.

“We know that burning wood and coal releases fine particulate matter (PM2.5) – the most worrying form of air pollution for human health,” said Sarah MacFadyen, head of policy at the charity. “It’s therefore important to consider less polluting fuel options to heat your home or cook with, especially if coal or wood is not your primary fuel source.” ”]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17740 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17740 Sun, 12 Feb 2023 13:26:59 +0000 ecosar I have had my wood boiler/range system heating CH & DHW for about 6 years. I have a thermal store.

increasingly more often the loading valve ESBE ltc 200 cycles on and off (I assume it is the pump I can hear), in a manner that I believe to be a servicing option, manually activated by turning the adjuster the opposite direction to normal. I am not turning the knob, but do wonder if it has somehow got turned. I have lost the manual and cannot find ltc200 on Ebse site.

The loading valve pump is activated by a flue stat, which I can adjust.

I have struggled to get an engineer out for several years and am wondering if any one here knows about loading valves and can help me work it out?

Thanks,
Sarah]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17429 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17429 Thu, 24 Mar 2022 17:02:53 +0000 owlman The heat pump industry itself was perhaps somewhat to blame in that it continued to label A/A as Aircon, a more canny approach from this industry may have been to label them as " air source reverse cycle heat pump " which may have got them included in the initial heat pump plan.

I came across this recently from BESA :-

APPLICABLE VAT RATE ON HEAT PUMP INSTALLATIONS
The purpose of this technical bulletin is to advise members of changes to the VAT rate
announced in the Chancellor’s Spring Statement of 23rd March 2022.
1. BACKGROUND
In July 2014 HMRC introduced a scheme for applying a reduced rate of VAT of 5% on energy
saving materials and heating equipment. It followed on from the enhanced capital allowances list of
previous years whereby heating equipment which featured on that list could have a 5% VAT rate
applied when the products were installed in domestic situations. The move was designed to
encourage the uptake of energy efficient heating systems such as heat pumps in retrofit
applications.
In October 2019 the rules were subtly changed to incorporate a “60% test” that must be applied for
the reduced rate to be used if certain social policy conditions are not met.
The Spring Statement of 23rd March 2022 has reversed that 2019 ruling as from 1st April 2022
meaning that the social conditions and 60% requirements no longer apply at all. This has been
implemented to incentivize homeowners to install energy saving heating materials as part of a
wider package of Government measures targeted at improving energy efficiency and driving the
decarbonisation of heat agenda.
The zero rating applies to installations of these products and therefore cannot be applied by sellers
of equipment only.
At this moment in time the zero rating can only be used by contractors in Great Britain as the EU
need to agree to this move for Northern Ireland. HMRC assured us that they are working on this
being a UK wide initiative as soon as possible.

2. VAT NOTICE 708/6 – CONFUSION OVER DEFINTIONS1
In February 2021 an amendment to clause 2.17 Air source heat pumps was made to correct a
mistake where air source heat pumps of the split air conditioning type had been specifically ruled
out from the scheme. There remained a large element of confusion across the sector, however,
and the issue persisted. After extensive talks between the BESA and HMRC the guidance has
been updated to clarify the applicability rules and allow air source reverse cycle heat pump air
conditioners in the same way it applies for monoblock heat pumps.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17693 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17693 Tue, 10 Jan 2023 20:10:03 +0000 eniacs
Weve a 12'000L pool in the garden that is dormant in the winter. Its temperature slowly follows ambient, it will take weeks to get down to 5 deg and then weeks to go back to 10 deg too.

Basically Im thinking to use a heat pump to cool the pool water and heat the house. The heat input to the pool would be able to be PLC choosen, ie if the air temp is above pool water temp then run a fan coil and pump to "warm" the pool water from ambient air.

I know its a drastic solution to a simple problem of low COP but my mind keeps going back. Maybe its the engineering challenge.

Has anyone seen a similar project?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17643 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17643 Wed, 16 Nov 2022 11:36:06 +0000 Peter_in_Hungary
Some thoughts

Heat load for the coldest month (kWh) / 30 = CH power demand for a day

CH power demand for the day / (how many hours ? ) = size of heat pump for CH.

DHW is fairly constant throughout the year so a daily consumption is easy find so –

DHW power demand for the day (kWh) / (how many hours ? ) = size of heat pump for DHW

But is the CH load on top of the DHW load or do you target the hours run so that e.g. CH needs 10 hours run time and DHW needs 5 hours run time = 15 hours run time a day so that the heat pump needs to be sized only for the greater of either load.

Playing with the target run times for each of the CH and DHW will alter the planning size of the heat pump.

But what should the target run times be ?? And how much spare should capacity be built in ?

Or have I got it all wrong?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17685 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17685 Sat, 31 Dec 2022 22:44:47 +0000 Newbuild https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17669 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17669 Sat, 17 Dec 2022 12:38:12 +0000 freemp31 I have opted to mount them at ground level because my roof is E/W aligned, and the S end is shaded by trees, plus the fact that I have 3 hectares of land which is just grass.
However, to get sun for the maximum day length, the panels will need to be some 40M from the tank, which sounds like a hell of a lot of cold water needing to be circulated from the manifold before any heat gets to the coil.
A Laddomat (which I have on the accu's primary circuit from the gasification boiler) feels a bit like overkill - especially at their current price - anyone found a reliable solution to this problem?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17619 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17619 Mon, 24 Oct 2022 12:57:40 +0100 owlman If possible, I realise I would need a three-phase supply in order to get a boiler with sufficient output to feed a 2000l buffer tank. The beauty of the idea would be that everything else stays the same with only the heat source changing.
I wondered if anyone had attempted this?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17666 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17666 Wed, 14 Dec 2022 09:42:20 +0000 Swarm
I know about units like Zehnder filter box but am nervous about fitting them to an otherwise functioning MVHR unit. Cutting pipe work etc.

Has anyone else dealt with this problem? Are such units simple to fit?

I also wondered about buying some hepa filters designed for vacuums and sealing them inside the actual room outlets. If I remove the outlet there is a plastic plenum? box that could fit a filter and I could seal around it. I thought maybe that the cumulative area of these filters over all the house outlets could be similar to one large filter next to the main MVHR. With the bonus I wouldn't have to modify the main unit pipe work.

Finding a suitable size filter is challenging but I should be able to. Worth a go maybe?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17646 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17646 Mon, 21 Nov 2022 11:56:19 +0000 Victorianeco
Any recommendation on suppliers? I need one with easy fit pipework

Thanks]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17337 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17337 Mon, 27 Dec 2021 14:07:30 +0000 Buz
I’ve recently had a Cordivari Combi Eco 2 thermal store installed which is fed from a Charnwood Cove 2B wood burning back boiler stove and so far not impressed.
The problem is the store just isn’t getting up to more than 40 degrees (output quote from manufacturer as wood room 4.6 boiler 6.5, anthracite room 7.1 boiler 9.3) there is a Laddomat 21-60 three way valve which recirculates the boiler water until it reaches 53 or 63 degrees (depending on which thermostat valve is installed) and then opens to allow hot water to fill the tank but I can’t get the valve to open as temperature is too low. The boiler to tank pipes are 22mm and approx 8 metres and the heat dump radiator is fed in 28mm and approx 5 metres from boiler, rad is is per recommendation on data sheet.
Do you think the boiler is man enough to supply the tank volume and the issue is elsewhere or am not generating enough heat from boiler, at the moment only burning wood but delivery of anthracite coming soon for me to test. I have had it running for approx 5/6 hours a day and 3 days straight.

Thanks in advance for any wisdom shared :bigsmile:

Cheers
Pete]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17641 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17641 Sun, 13 Nov 2022 17:55:01 +0000 Erkindik
Has anyone installed a systems like this? What sort of performance have you seen?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17638 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17638 Thu, 10 Nov 2022 15:23:00 +0000 revor https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17616 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17616 Sat, 22 Oct 2022 11:43:57 +0100 HoveTom
I have a subfloor with wet ufh in place already and will be having engineered parquet laid over the top soon.

The blocks seem to come in 10mm, 15mm and around 20mm thicknesses. I’m wondering which thickness is best? I’m guessing the 20mm thick blocks take longer to heat up but perhaps retain their heat for longer so are better overall? No idea hence the post here.

My kitchen/diner has a new solid floor with around 150mm of insulation and around a 45mm screed layer ontop. The rest of the house has a suspended timber floor with around 75 mm of PIR insulation between the joists and then the ufh laid in about 20mm of a dry sand and cement mix on top. This is covered with Knauf Gifa board which is 18mm thick and has very good thermal conductivity (about 4 times that of a a chipboard subfloor).

I’m thinking the 10mm blocks may be just too thin (they have the same wooden wear layer as the 15mm blocks) and so not very strong and that the 20mm blocks are unnecessarily thick. So leaning towards the 15 mm block, does anyone have any experience, good or bad?

We like the 'tumbled' look which is when new blocks are thrashed around in a mixer with stones to knock the edges off them and make them look a little older. In order to survive this process most tumbled blocks are around 20mm thick. 15mm tumbled blocks can be bought but there is less choice.

Any experience appreciated.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17596 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17596 Fri, 07 Oct 2022 10:14:34 +0100 neelpeel The room is insulated, but I still think it must waste a great deal of heat, especially in the summer when the heating is switched off and only the hot water is left running.

The wasted heat I think comes from the need to heat a buffer tank. Is there a way to switch this feature off or bypass it completely? I know this would mean waiting for longer for the water to heat when having a shower, but I'm willing to live with that and use the kettle for most hot water needs.

The boiler is a 15 yr old Grant Vortex Outdoor Combi.

I had considered directly insulating the boiler, but I guess that could overheat the components and lead to speedy boiler death?!]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17603 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17603 Thu, 13 Oct 2022 03:11:47 +0100 omehegan
Now I'm thinking about the future, and what I would replace this boiler with when it's time to get off gas completely. It's just an academic question at the moment, but I am wondering what others would suggest. The house doesn't have ducts, and adding them would be complex, so any kind of ducted central system is probably out. Mini-splits in each room would be feasible and may be the way to go, ideally if I can control them from a central point. But the hydronic heat is nice for comfort, and I prefer it to fans and hot air blowing around the place. However my impression is that air to water heat pumps struggle to match the efficiency and performance of air to air ones for home heating. I suppose the other upside to air to air is that they can provide cooling in all rooms as well, something that we don't have today... I also note that there are more exotic things, like the Tepeo ZEB boiler. Maybe something like that will be a better option.

Thanks in advance for any thoughts!]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17549 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17549 Thu, 25 Aug 2022 21:02:53 +0100 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17527 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17527 Thu, 28 Jul 2022 12:21:33 +0100 tony
Bleed your radiators. Trapped air can make your radiators less efficient, so they'll be slower to heat up. If you feel confident doing it yourself,….

I disagree! The use of the term efficient winds me up again

I think that they might mean, ‘Trapped air can make your radiators deliver less energy’ which it could be a good thing as bills will be lower.

Bleeding the ‘air’ out will help them deliver more heat to the home and use more energy and cost more.

Again the opposite of what they were saying it would do (use less energy)]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17516 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17516 Fri, 15 Jul 2022 18:28:45 +0100 Swarm
I assume it should at least be able to cool one room for sleeping in and all hot air would just go up the vent and out through the mvhr without much issue, other than perhaps warming the incoming air slightly for the rest of the house.

None of my windows are suitable to vent out of, thanks to internal blinds needing to be closed and windows opening inwards. Plus it would be preferable not to let in warm air!

Is this worth considering or are there some gotchas I haven't thought of?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17509 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17509 Wed, 06 Jul 2022 23:37:15 +0100 Followthemoney
Not permitted to put solar thermal on roof or anywhere near house. Solar PV is only practical generation we can install in a field about 80m from the house.

We have 'twin phase' electricity supply (two single phase mains through two separate meters, two consumer units) use average 16kWh/day of electricity. In winter around 18L/day oil and in summer 7L/day on domestic hot water (300L cylinder) and keeping the under-floor slab ticking over.

A neighbour has 17kW PV (the max permitted 1ph grid tie) and in Nov / Dec / Jan it delivers average 10kWh/day. Not much, but enough to run the dishwasher and supplement the hot water. May / Jun / Jul / Aug it's 60 to 70+kWh/day.

My take-away from these figures is go large because PV is relatively inexpensive and aim to export nothing we don't have to. I think we might get permission to grid-tie 8kW to each incoming main, and this is about the max size of domestic 1ph inverters.

So, proposal is 24kW PV array, 3 x 8kW 1ph inverters, two of which hooked into our existing consumer units. 1500L accumulator tank fitted with 9x 2kW immersions. Set up the demand management to favour any domestic load, followed by the lower immersion in the domestic hot water tank. Any additional energy (in 2kW increments, as available) from the two grid-tied inverters to the accumulator, plus all the energy from the third inverter.

On average mid-winter day we should get a chunk of our domestic demand covered, plus most of our hot water. For the other 9 months, and particularly Apr to end Sept there should be 75 to 100kWh/day (on average) Knock 30kWh off for domestic use and hot water and that leaves 45 to 70kWh for the accumulator, saving maybe 4.5 to 7L of oil we'd burn otherwise. The 1500L accumulator should store around 70kWh if the mass of water is heated from 45C to 85C, then extracted to a heat exchanger on the central heating circuit.

No PV installer is much interested in this plan, too much plumbing and a bit left-field, but what does the community think?

P.S. I've considered batteries and calculated that they are no friend of the environment or my wallet, even with electricity at 35p/unit. One of the problems Is that we would need two batteries and charge controllers for each 'phase' of our supply, doubling the cost.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17486 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17486 Sat, 11 Jun 2022 12:03:05 +0100 RobWeir
First post - I'm a long time lurker, it's a great site but it's taken me 15 years to get around to finalising and commisioning my heating system..

I’d like some help please, selecting the right TMV and pump for mixing down the Central heating supply temperature - being taken from a 350litre tank (working partly as a buffer tank, partly thermal store). This is probably quite a simple problem for professionals and folk that have done it before, but I’m doing all this for the first time (I’ve split an old pub into two, so I’ve got a second more complex living unit to do after this one).

Should I use a TMV and Grundfoss pump (like a lot of UFH systems) – or a motorised valve (which must need a controller and add complexity and cost).

I’m struggling to ID a good value Pump/TMV array that will output 70-80 deg C water and accept 95 deg input. The standard UFH and DHW TMVs regulate to lower temperatures than I think I want…

This is for a Wood stove backboiler based heating system. I’m using a single vented 350 litre tank/thermal store for DHW and CH, fed directly from a woodstove/boiler, and indirectly by Solar (and possible in future by Heat pump – but I’ve no dedicated coil for that).

I’ve only got a single 15mm flow and return circuit feeding 3 rooms (plus a towel rail). 2 bedrooms with TRV and a living room which has thermostatic controller built into the fan convector.

I’d like the freedom to bring the tank up to its maximum safe working temperature (90-95 deg C say) so as to maximise the thermal heat storage capacity of the tank.

The Overtemp safety valve on the Woodburner is set to 95 degC. The cylinder manufacturer recommends a 90 deg max temp (‘to avoid boiling’), and my main open plan living room radiator (a DIMPLEX SmartRad fan convector) states max CH Feed temp should be 85 degC…

Please check out the attached diagram (cobbled together but quite representative).

MAIN QUESTION(s)...
Can you suggest a Thermostatic Mixer Valve that will provide adjustment between say 65 and 80 degC? Can you suggest a CH pump that is right sized for this size of job.
If I am sourcing separate Pump and TMV does the pump always go downstream of the TMV?

Controls: I wasn’t thinking of switching the pump on and off with a room thermostat, I was hoping I could use a basic timer with a simple on/off manual override. In this case I’d want the flow rate to throttle right back (to nearly zero?) when the TRVs were all closed off? Is there a smart pump that does that? If I need a bypass VV I’ve seen a suggestion (here) to bypass in a loop back into the supply line (wouldn't it be better if the bypass was fitted from the output of the pump back to it's input? That way it wouldn't stir the thermal store?).


GENERAL THINKING ALOUD…
There seem to be three good reasons for a Thermostatic Mixer Valve (or equivalent motorised VV) in the CH supply. 85 deg C is what Dimplex have specified as a max supply temp. Mixing down would improve or rather maintain stratification, and it should reduce any burn hazard for occupants. Note that all 3 of the room radiators in the house are Low Surface Temperature designs.

There is a good reason to allow quite a high CH supply temperature…I am using a fan convector in the main open plan kitchen/living area, as part of a ‘low thermal mass’ heating approach. This convector is oversized (maybe 5 times) by conventional standards. The intention is to be able to heat up the room so fast that the heating can be off when the room is not being used, or when the occupant is out of the house. The higher the feed temperature, the easier it is to make the occupant feel they have access to ‘instant heat’, and so can allow parts of their house to be cool when they are not in use.

I’m pretty sure 70 degC CH Flow temp would perform adequately as a maximum temp but I am truly lost looking to source the right pump and TMV on the web - there is so much choice and variation in cost.

I see lots of mass market DHW and UFH mixer valves that seem good value, but when I look for a TMV or a load unit spec’d to 65-80 deg C I cannot find them or the prices seem to be 3 times higher. Am I looking in the wrong places or at the wrong things? Should I be buying separate Valve and Pump components for best value/compactness?

Pump wise - I was considering a reconditioned Grundfoss pump (off of a well known auction site). The house has such a small system with TRVs on all the radiators that a small modulating pump is not needed to be working very hard so a pressure sensitive pump that modulates down to nearly nothing would be good.

EVEN MORE BACKSTORY
I’ve rebuilt a small listed pub in a Scottish village, splitting it into two housing units.

I’m commissioning the smallest 2 bed unit first. It is about 70 m2 with MVHR and a design heat load of under 3 kW. It has a single downstairs open plan living space, with two bedrooms and a bathroom upstairs. There are only 4 radiators on 15mm pipework in the house, all with TRVs.

There is a single vented thermal store (350 litres) for DHW and CH, which is directly heated from the Wood burner (through a load unit). The stove is supposed to output 2.3 kW to main living room and 6.1 kW to the water (but who knows). The stove has a thermostatically controlled damper on an external air intake.

There is a solar coil which I’ll probably have to hook into a wet solar thermal panel system for summer DHW. I’m really tight for space locating panels, otherwise I’d put in PV with an immersion heater for simplicity. I can’t use the roof because the building is listed, and I’ve very little unshaded yard space for PV panels so it has to be Solar Thermal, or maybe just use the Solar coil for a Heat pump option instead.

The bedrooms have small (Low Surface Temp) radiators and the main room has a fan convector unit (DIMPLEX ‘SmartRad’ SRX180EM). I am using a Fan convector so that heating can be switched off when house/rooms are unoccupied (because the convector can heat up air quickly when occupied).

Of course, the Convector gives me the option of using low grade heat when the store is nearly exhausted or to maintain a good COP if an air/water heat pump is added in future (I’d like to think in the long run we’ll most of us have access to a district heating scheme).

My initial building warrant was approved >15 years ago, utilising a small oil boiler. So I need to redo the SAP calcs and submit B. Warrant changes adapted to whatever is now allowed!

In winter, I’m expecting to light the fire (in the downstairs living space) each night. The intention is for there to be sufficient energy left in the store tank to have a shower and heat the living space for breakfast without relighting it, then go out to work leaving the heating off. Ideally there would be a smidgeon of heat left in the evening to take the edge off whilst the stove is lit!

My plumber is good, but hard to get hold so I’m making all the design decisions, buying the gear (possibly reconditioned Grundfos pumps) and mocking up the pipework …so he can make a neat compact job as fast as possible, when he gets a moment. We’ve got Solar, Wood Boiler and possibly a future Heat Pump CCT as well as DHW and CH… in quite a small airing cupboard space!!

When I’m happy with the small unit I’m doing similar but more interesting stuff in the adjacent 4 bed unit which is heated only with oversized convectors and uses a 1000m3 Thermal store.

Sorry to say so much – any comments on any aspects welcome 😊.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17491 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17491 Thu, 16 Jun 2022 22:54:09 +0100 1980scotland
Wondering if I can pick your brains on a fairly well worn subject.

I have a solid fuel Rayburn which I rarely use - boiler current removed and replaced with a heat brick. I use an ASHP for heating and hot water. With electric prices, have the feeling I should integrate by Rayburn boiler somehow. I have a sealed system, no thermal store - the ASHP heats UFH and DHW tank directly.

The floor height of the water tank is approx 1m below the Rayburn floor height. I am wondering about adding a buffer tank somewhere, and then linking that in to the existing system.

Thoughts appreciated. Since I have the Rayburn, the Rayburn boiler and the existing system - wondering if I can add a few system parts and do this integration.

Cheers]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17475 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17475 Tue, 24 May 2022 08:48:27 +0100 Barnacle
I just wonder if I hang on for a year or 2 when more companies are doing ASHP retrofits how much will prices drop? The current quotes seem pricey to me - but maybe I'm being mean.

Thoughts and experience please :bigsmile:

* initial quotes - without doing full heat loss calculations to see if I'm prepared for the level of expense. The companies all said it takes about a day for them to carry out the full heat loss calculations.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17471 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17471 Tue, 17 May 2022 07:36:40 +0100 tony
What temperature should a lounge be , during the day? During the evening, During the night, during the morning?

Ditto other areas?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17447 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17447 Wed, 13 Apr 2022 09:45:48 +0100 Shevek - 1 bathroom with bath/shower, 1x washing machine, 1x dishwasher (we'll occasionally have all running at once in the evening, including 2x showers)
- currently just the 2 of us, but plan to have visitors often and it may well get rented to 4 person family
- Considering the Aquapura Monobloc: https://www.energie.pt/en/products/aquapura-monobloc

The question is 114 lire (maybe too small) vs 195 litre (maybe too big)? (120 model vs 200ix model)

Is it true to say that we'll mostly only pay for the water that we use rather than what we store, so therefore it's better to slightly oversize than to slightly undersize, so we don't risk running out?

The 120 also has a COP of 2.8 while the 200ix has a COP of 3.72. What does this mean in the context of sizing?

(some additional context: had a quote to get the 200i installed for €2600, and we should be able to get 85% of this back through EU funded programme here in Portugal for energy efficiency upgrades)]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17361 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17361 Tue, 18 Jan 2022 10:59:04 +0000 CX23882
As much as I'd love to retrofit UFH, there isn't sufficient depth available, which leaves radiators, and there are two main options:
1) Traditional trunk running through the loft, coming down the walls to radiators, each with TRVs.
2) Centrally-located manifold with electric actuators, controlled by remote thermostats in rooms. No TRVs on radiators.

In both cases, any in-room pipes would be surface-mounted and boxed in, vertical drops behind MDF boxing in the corner of the rooms, horizontal runs behind skirting.

Is a manifold/actuator-type system overkill in a small property (approx 100m^2, single-storey)? The thing I like about it is:
1) each thermostat will be away from the radiator, so gives a more accurate room temperature.
2) multiple radiators in a room can be controlled together.
3) when the room doesn't require heat, the relevant pipes won't be circulating and thus wasting energy.
4) the potentially noisy moving part is in the utility room or loft, rather than on the radiator as with TRVs.

Biggest downside I see is that there is more pipe (and hence water to heat, when all rooms are calling for heat) overall, since each radiator gets a dedicated feed and return pipe.

With a manifold system, you could potentially run PEX all the way from the manifold directly to a radiator, without any joins. I don't see how that approach could work in a retrofit with solid floors and walls, because of the minimum bend radius of the PEX. A 10cm radius is already the height of skirting boards. It seems the logical approach is to use copper below the radiators for the last leg (or maybe down the walls too). By that stage, you may as well swallow the cost to run copper through the loft too and solder the entire lot.

Other than the leaking and inefficiency of one-pipe, the existing system was very loud with expansion noises (mainly the pipes themselves expanding in the screed), so the replacement system needs to be as quiet as possible. The best way to do this seems to be to lag all pipes, and tie-down over the lagging, rather than by clamping directly to the pipes. I'm concerned about how noise-reduction fits in with air-tightness through ceiling penetrations. One option is to accept a bit of extra bulk in the pipes running down the wall, and wrap them with some thin Armaflex sleeve/lagging as they pass through the ceiling (as they will be with the thicker insulation in the loft itself), and re-seal the hole up to the lagging.

Any advice/input greatly appreciated.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17442 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17442 Sat, 09 Apr 2022 11:51:41 +0100 minisaurus I wondered if anyone would like to help me check my calculations?

We have an ASHP that runs 24/7 at 45 litres per second. The average yearly outdoor temp for where we live is 8 degrees C. We like to have a room temperature of 21 degrees C.

When in my (swedish) college, to calculate the energy requirement to heat intake air, we used this formula

P [kW] = q [m3/s] x R [kg/m3] x delta T [degrees C]

where:

R = 1.2
delta T = indoor temp - average outdoor temp

We'd then multiply the result by 8766 hours to get the (approximate) yearly requirement in kWh.

So for my house, that would give:

P = 0.045 x 1.2 x (21 - 8)
= 0.702 kW

0.702 kW x 8766 hours = 6154 kWh.

Sounds reasonable?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17432 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17432 Wed, 30 Mar 2022 22:45:52 +0100 neelpeel
I currently have an oil combi-based central heating system and a small wood burner that can pump out a fair heat (practically heats the house with the doors open). As you may have spotted in my other thread I am considering installing an ASHP to reduce my reliance on both - mainly to reduce my 'carbon footprint' and I suppose hopefully reduce long term costs.
I thought I'd work out some rough calculations for each. I estimate my heating need as 14,000kWh/year.
(CO2e estimates from https://www.carbonfootprint.com/calculator.aspx)

Heating Oil
14,000kWh = 1,353L I think I then need to assume 90% efficiency, so about 1,500L
1,500L = 3.8Te CO2e/year
Assuming £0.60/L long term ave = £900/year

Wood Burner
14,000kWh = 3.33Te dry stacked hardwood = roughly 7.9m3
3.33Te = 0.24Te CO2e/year
8m3 dried hardwood logs locally = £950/year

A/A ASHP
14,000kWh output at an average COP of 2.5 (??) = 5,600kWh electricity input
5,600kWh = 1.29Te CO2e/year
Assuming £0.22/kWh long term ave = £1,230/year

So regards CO2e there are massive differences and wood burner is top of the pops.
Here I should note that I have no close neighbours, the nearest village is 3 miles away and the nearest town is 7 miles away so my assumption is that small particle air pollution is not really a concern for my woodburner (correct me if I'm wrong!)

And regards cost...not much in it, but possibly not looking worth the cost of installing an ASHP - if I can be bothered to feed the wood burner like a demon possessed.

What am I missing??]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17428 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17428 Thu, 24 Mar 2022 10:25:36 +0000 neelpeel Space to heat will be 90m^2 total and about 210m^3 volume once extended.
The ASHP will be supplemental heat to reduce the use of our oil burner and wood burner as much as possible.
I'm in Aberdeenshire, so temps often hover around 0 - 5degC in deep winter, but anything near freezing and I would be expecting to put the wood burner on anyway.

Which Air-Air Heat Pump brands/models should I be looking at?
How noisy are the pumps? Are they suitable for a living space?
What is the life expectancy of the latest pumps? (I often hear disaster stories about multi-room ASHPs going wrong and no available bits to fix)
Any experiences (good or bad) to share?

Looking at one model as an example - Daikin Perfera FTXM20R
Nominal heating = 2.5kW (does this mean 7.5kW equivalent at a COP of 3?)
Seasonal Efficiency SCOP = 5.10 (how this equate to a COP at 0 degC, 5degC, 10degC??)
Are manufacturers not obliged to show charts of COP vs temperature?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16567 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16567 Thu, 21 May 2020 19:13:38 +0100 DamonHD
The aim is to be able to selectively draw some space heat from electricity when its carbon intensity is less than that of using gas directly. No storage. No HP.

It's meant to be cheap and simple. (Combi is a Potterton Performa 24 FWIW.)

Rgds

Damon]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15257 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15257 Fri, 25 Aug 2017 15:50:16 +0100 geoheated
I am installing my 6kW Heat Pump next month. Over the winter i renovated the entire house, Insulated, installed underfloor heating on both floors in all rooms with 116mm pipe spacing.

I have purchased the heat pump and just need to dig the loops in the field.

Location:
At the bottom of the field, 50m from the house, its a valley with a steam running through it. During the summer it dries up typically.
I will run straight pipes parallel with the stream, digging 1.5m deep i can get down to below stream level.
Its the end of August now, we have had a damp august, stream is dry, but when i dig to 1.5m its wet clay going into sand at the bottom of the trench. See photos. (IMG_3334 is after 48 hours) plenty of water in the ground all year i suspect.

I purchased a report from the British geological survey. They confirmed we are on sandstone with a thermal conductivity of 2.59W/m.K.
I spoke to them, as this is the bedrock figure and we wont hit that, they suggested 2.5W/m.K. as i have just hit unconsolidated sand.

Looking at the MCS lookup tables, wet sand is 2.4W/m.K.. So i have gone with that figure.
Average ground temp at 1m is 11.6c from their report.
I measured the ground at 1.5m immediately the excavator dug it and it is currently 16.3C in August.

Sizing
I plan to install enough to satisfy the house demand when we hopefully extend in a couple of years! This would mean upgrading to a 8-9kW heat pump. I have run calcs for both initial and proposed sizes. I intend to install enough pipe now to satisfy the larger pump.

I have a old 3Ton Kubota i plan to spend a few days sitting on to do this work!

Pipe will be PE100 32mm.
I dont plan to blind with sand. There is 0% rock in the ground and at 1.5m i am into sand.

The MCS tables only reference 25mm pipe. Using 32mm i expect a slight increase in thermal absorption ,but i wont attempt to factor that into the design

My Question Is:

The tables talk about 750mm pipe spacing.

I plan to dig a 400mm wide trench (its the bucket i have). At 400mm it seems reasonable to lay 2 pipes in the trench at 400mm centres.

MCS calculations and table suggest 182m of pipe for my 6kW.
Then 335m when i upgrade to 9kW.

Would it seem unreasonable to lay 400m of pipe in 2x 200m trench, pipes spaced at 400mm in the trenches, with 1.5m between trenches. With the plan to be well oversized initially, and suitable for when i put the bigger pump in.

I read somewhere that 300mm is good practice to avoid thermal interference between pipes.
But as MCS tables reference 750mm, does my extra 65m (20%) cover the fact im 400mm centres.....?

Initial Dig Conditions. Clay into Sand(Grey).
https://postimg.org/image/epei37y3n/

Ground Temp measurement during dig.
https://postimg.org/image/93s2z5xer/

After 48 Hours.
https://postimg.org/image/f5zppnlur/

Sizing calcs for current 6kW HP.
https://postimg.org/image/6p07eqh5v/

Future 8kW HP Calcs.
https://postimg.org/image/f9y4jngpv/

Location.
https://postimg.org/image/ebhrhd3dv/]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16907 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16907 Mon, 25 Jan 2021 18:41:45 +0000 greenfinger
Sorry to be hogging this sub-forum!

I'll be having a 6kW wood stove installed soon. It's an old house, so we get the first 5kW for free and only need to provide air for the remaining 1kW. From what I've read, this needs to be 23mm x 23mm for square, or 26mm diameter if round. We don't want any large grill faces or anything like that. Would prefer it to be visually as unnoticeable as possible. Can't do anything with the window, as that's being replaced in the future.

So...

- Would it be best to do one hole to spec, or several little holes?
- Can anyone work out what size the little holes would need to be if doing a few? Or is that as simple as dividing 26 by the number of holes?
- My installer said it would be enough to just have the holes lined... Any ideas what's best to use?
- How to make the holes rodent mouse proof?

Also, I've read several times how random the nominal rating of stoves is... How 5kW stoves can be largely different in physical size, have different sized fire boxes and therefore different fuel loading capacities, have different ranges (the Arada Ecoburn is rated 1.5 - 9Kw, whereas the Clearview Pioneer is rated 1kW - 5kW)), and yet all be rated as nominal 5kW. And on top of that, how the testing of stoves is very artificial and easily manipulated to reach a desired rating. With all that in mind - and forgetting HETAS, regs, etc for a moment - how much real life need is there for an air vent with a 6kW stove installed? For the record, the stove is a Woodwarm Fireview 6kW (5.8kW nominal to be precise).

Many thanks

(PS - We'd love to have a direct air feed but for several reasons it's just not possible.)]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17383 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17383 Wed, 09 Feb 2022 08:46:14 +0000 Dur
Apologies, as ever, if this has been covered before but I can't find anything much.

As part of an extensive renovation, we are wanting to fit an ASHP but we have fairly feeble water pressure/flow and so have a 100 gallon header tank in the loft currently feeding a traditional vented copper hot water tank with 22mm pipes on the main runs all in as new condition. So while not much else in the house works as yet, we do have a decent shower and wouldn't be happy with a shower at mains flow/pressure.

Our potential supplier /installer would like to fit a 300 litre high gain unvented tank which I think is a pretty standard approach. He has looked to see if there is a vented equivalent but to no avail.

So I am hoping for some help on potential options that maintain the efficiency of the purpose made unvented tanks but give us the advantages of the old fashioned system ie good flow and the ability to have two showers running and no dip in flow if someone fills the kettle.

I guess we could have a pumped pressure set using the loft tanks as break tank/ reservoir but that is more hardware and complication (and we lose water in a powercut).

Are there any other approaches we can look at?

Thanks!]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17348 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17348 Tue, 11 Jan 2022 17:07:25 +0000 Tomasz_P My plumber installed a 6kW Grant unit. The makeup of the ground floor is roughly 100sqm limecrete with 2-300mm foamed glass under that. Walls are mostly 60mm woodfibre with lime on 5-600mm brick walls. All windows are currently single glazed and I still have some draft proofing to do around the front door.
It has now been running constantly for a month and has only managed to get up to around 18-19C room temp but more like 16-17 on the coldest days. I was concerned before it was installed that we should have gone for the 10kW but he was sure it would be enough. I will be installing wood burners for the colder months as I have a good supply of my own wood but I would prefer if it could cope on its own if needed. How does this sound to those with experience? I I guess I should do some of my own calcs. Is there a site where you can input data to do this fairly quickly?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17354 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17354 Fri, 14 Jan 2022 19:19:01 +0000 Nick Parsons
Cheers,

Nick]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17335 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17335 Wed, 22 Dec 2021 16:05:47 +0000 greenfinger
I'm not finding anything beyond 650C after an initial search. Does anyone know if higher temp paints are available? It's for internal parts, not the stove body.

If 650C is as good as it gets, is this suitable? It's not specifically for stoves, but...

https://www.toolstation.com/high-temperature-spray-paint-500ml/p64927

Cheers]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17265 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17265 Sun, 31 Oct 2021 16:41:50 +0000 alant The above would require a separate store / tank for the stove input. I guess a simpler solution would be be 1 thermal store with immersion heater for summer use and fed by stove boiler in winter time?
Any other possibilities?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17255 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17255 Thu, 28 Oct 2021 10:25:34 +0100 wholaa
"Your correspondents are too gloomy about heat pumps for houses and flats (Letters, 20 October). Heat pumps may be unusual in Britain, but they are a major industry and very widespread in Europe and elsewhere. They are used in Canada, where outside temperatures drop very low. Individual units may not be suitable for high-rise blocks – although they might be installed on balconies. But high-rise buildings make up a small fraction of the housing stock, and blocks can have communal heating and cooling with large centralised heat pumps.

Older heat pumps were noisy, but new makes are on the market that are much quieter. *It is not true, except in the worst cases, that installing heat pumps requires dwellings to be insulated first. The great majority of houses and flats in the UK are already reasonably insulated,* and heat pumps can be run for longer and at lower temperatures than gas boilers. *Better insulation of existing gas-heated houses and flats will by itself only produce modest cuts in carbon emissions*. To meet climate goals, we have to stop using gas.

And, by the way, hydrogen as a domestic fuel – being pressed hard by the gas companies – is a distraction. It has to be made either from natural gas, which produces CO2 and can also release methane, a much more powerful greenhouse gas. Or it can be made with electricity, by the electrolysis of water. But why would one not in that case supply the electricity direct to houses, for resistance heating, or for powering heat pumps?
Philip Steadman
UCL Energy Institute"

Isnt his statement dubious? Is the average UK house already suitable for heat pumps? Personally, I would be concerned if gov policy was inspired by such a statement. He might be right that UK houses have reasonable insulation but they need far better airtightness to make heat pumps sensible. Roger Brisby has a video where he predicts a lot of people will be misold heat pumps and it seems a reasonable prediction.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17260 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17260 Fri, 29 Oct 2021 10:54:54 +0100 WeeBeastie
I understand direct electric heating can be frowned upon here, but I am in a situation where I need it for perhaps a few heating seasons due to staging of works.

Calculators tell me:
1.2kW for a living room
1.2kw for bedroom 1
1.0kW for bedroom 2

My priorities are heaters which are quiet, have integral timer + thermostat (I don't need or want Wifi or smartphone control) and at the cheaper end of the price range. Wall mounted, not portable. I'm not too fussed about the warm-up time or 'feel' of the heat. Ideally not too ugly! So something fairly basic.

Any suggestions? There are some inexpensive panel/convector heaters out there (e.g.Mylex, Stiebel Eltron) - are these fine?

Thanks.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17259 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17259 Fri, 29 Oct 2021 10:40:41 +0100 luz13827
I think often people don't put UFH under cabinets because it could be a waste of energy in those areas, but is there any risk to the cabinets themselves? Or any appliances we should not have UFH below, e.g. the fridge/freezer?

The reason why I am considering having the UFH below, is that the kitchen cabinets will partly back onto an external wall, and so I think UFH would make sense as otherwise that wall would could potentially not get as warm, and could then lead to condensation behind the kitchen units, that we can't see. Does that make sense? We are of course doing everything possible to manage humidity in the home to limit the chance of this in the first place, but I'm thinking worst case scenario, if RH did rise. We have had mould issues in the past, so trying to avoid that at all costs.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17235 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17235 Mon, 11 Oct 2021 20:45:45 +0100 nbishara
Also refrigerated insulated pipes on outside of house…to the tank…bit surprised by this?
Thanks!]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17229 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17229 Sat, 09 Oct 2021 12:44:50 +0100 greenfinger
A bit of background: I live in the Brecon Beacons surrounded by a lot of trees and a stream, all of which I presume lends to the high relative humidity (RH) in my house. It often sits in the 70% region and sometimes even creeps above 80%. In times of high RH, opening the window is counter productive and causes it to rise. We use a dehumidifier when it's at its worse.

We have a wood burner in one room, which does not have a direct (external) air feed. It's not been in long, but it does do a good job of reducing the RH. We'll soon be installing a further two wood stoves. I totally see the sense in direct air in as much as it will minimise drafts, and negate the need for a vent which would let copious amounts of cold air into the house...

But when it comes to humidity I can't get my head around it. No direct air to the stove means more air changes and air circulation in the house (I think?), which could be looked upon as a good thing. But then again, it also means more air coming from outside, where the humidity is higher, so perhaps it isn't such a good thing. And maybe that's all too basic a way too look at it anyhow.

I wondered if anyone out there has a better understanding of the science behind this and could explain which option is best and why, when it comes to humidity?

Many thanks]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16744 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16744 Mon, 05 Oct 2020 21:12:19 +0100 topher
I need about 15 kW output and ideally 70 degrees for rads and hot water, from a single phase supply. At this early stage I am thinking that I remove the existing gas boiler and put the ASHP in its place. I have an Evohome controller which I hope I can continue to use.

These are my questions. . . .
1. Who are the best manufacturers to look at?
I have found a Daikin product can provide 70 degrees water output
2. Where can I find a list of experienced installers?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17167 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17167 Tue, 24 Aug 2021 09:29:59 +0100 greenfinger
I'm in the market for a couple of wood stoves (or multi fuel, but no plans to burn anything other than wood). I'm very drawn to Dowling Stoves, but there aren't a great many reviews out there. And obviously they do things a bit differently than most stoves you see from the better known names.

So I wondered if anyone here has one if they'd be happy to share their experiences? Or for that matter, even if you don't have one but have thoughts about them it would be great to hear fro you...

Many thanks


https://dowlingstoves.com/]]>