I have recently moved into a 13 year old property which currently has electric storage heating. Bills to date are approx £1400 from mid December to end July. During this time there has been no heating in the bedrooms or bathrooms - so only really heating the main living space and hot water. Since May, almost all the storage heaters have been off (there are 8 storage heaters in total - and I am on Total Heating Total Control Tariff).

As a result, I have decided to change the heating system and would appreciate advice on what to replace it with. My thoughts are towards three potential solutions:

1. Ground Source - I don’t want to go down the road of installing underfloor heating so it would have to work with radiators (which I will have to buy anyway albeit 30% bigger). I have the space for a horizontal system, but rock could be a problem. Boreholes seem to be quite expensive.

My main concern is that I'm not totally convinced of the effectiveness of ground source with radiators and don’t want to go to big expense to be left with a solution that doesn't work effectively.

2. Air Source - to some extent I have similar concerns to those above regarding effectiveness with radiators. Another possible issue is that I am on the coast and suspect that the ASHP would be prone to rusting.

3. Wood Pellet boiler (self-feed). This is possibly my preferred option at the moment, although I still have to receive a quote. Seems to tick the boxes to some extent in terms of cost against oil and environmental impact. There seems to be limited information about wood pellet boilers (although I may just be looking in the wrong places).

The house is reasonably well insulated (Zone 1 - 32.8W/C and Zone 2 as 466.6W/C - not sure exactly how this translates - but most of the house is 'upstairs' with a games room downstairs). There is hardwood double glazing (not particularly clever, but probably sufficient), loft, floor and wall insulation.

I would appreciate any comments on any of the above or if there is a better solution that I might have missed, that would also be welcome.

Apologies for the ramblings!

Thanks Tony. You could be right - but I'm not sure. Wouldn't the energy consumption be the same regardless of the insulation? The storage heaters are going to charge up and discharge to the same extent across 24 hours regardless of the insulation levels.

That said, there was a serious draught blowing in from the conservatory. I discovered that there was no insulation up there and the hatch was a DIY job. I've since insulated and put in an insulated hatch. I've also raised the floor as there was cold air blowing in from a gap below the skirtings. Seems to be much better now.

It did cross my mind that the meters could be faulty.

There seems to be a trend developing with the suggestion of using Heat Pumps with radiators. I think it is a bad idea. Your Heat Pump should, optimally, be powered by Economy 7 and run only during the night. The heat should then be stored in the concrete that the underfloor pipes are bedded in (like a big night storage heater). Obviously you cannot do this if you have only radiators. So the Heat Pump will have to run during the day as well to meet demand from the radiators. This will be much more expensive to run as you will be using daytime tariff and the Heat Pump will be continually turning itself on and off. The alternative is to install a thermal store in lieu of the concrete underfloor heating store (additional expense and use of space) and correctly sizing this would be critical to ensure you didn't run out of heat.

Also I've seen figures that suggest that radiators need to be x2 the size (not just + 30%) to be used with the lower temperatures of Heat Pumps vs boilers.

So Heat Pumps & radiators could be more expensive to run than your current system.

The main issues with pellet stoves are storage space required for the fuel (smaller space = more frequent deliveries = increase unit cost of pellets) and, when I enquired, the pellet supplier wanted to sign me up to a 5 year contract!

Posted By: moogaloo... new funky radiators that work with lower heat water ...

I'd love to see the technical spec for one.

Hi, am just installing a heat pump in a new project. It is a fairly straight forward calculation on the radiator sizes which relates to the heat output required, and 30% is about right and is based of Newtons laws of physics. Although you will be using power to run the system during the day, the whole point of heat pump is that is uses far less electricity so on balance it is still cheaper than fossil fuels, even gas now that prices have risen dramatically,

There are also other options for using low rate power.
If you have electric heating then powergen will provide you with a lower rate for 18 hours of the day (around 5p), outside of peak demand, with a small effort you can set the system to operate so as to avoid these times, and that should also include your dishwasher and washing machine etc
If you are in north east anglia there are plenty of systems going in so you could speak to someone who actually has one. These forums can be excellent but you can also get opinions from people who don't have any direct experience of a system.
Heat pumps have been around for along time, in Sweden they have around 60,000, they are just new to this country so people are over cautious.

I think that you are right Mark about the wide ranging views, generally I have found that the heat pump companies in this country are small middlemen operations who are overcharging mainly for Scandinavian systems.
The initial prices that I was quoted were up to £10,000, but the system we finally used for a large 4 bed house was £4300 for heating and hot water.

The large airconditioning manufacturers are getting involved now and their systems are based on their existing airconditioning technology which have been reverse engineered.

As an architect I have a constant problem with new products in deciding who knows what they are talking about and who is telling the truth. This is especially true of sustainable technologies where everyone seems to have jumped on the bandwagon. I am sure that in a few years time the price will have dropped dramatically and that the smaller companies will dissappear.

Heat pumps work fine, the question is - does the house work? If there are air leakages, open chimney flues undraftsealed doors then it is probably better to install a system that can easily provide double the amount of heat you should really need to keep the house at a constant temperature. If you want to find the leaks look into having an infrared survey done so that leakages are identified and removed.

YES YES YES YES YES....I do totally agree with you about wasting energy, my point was really to say that if you install a heat pump and it doesn't work, it is because the house is rubbish not the heat pump or whether you use radiators or not.

If you aren't able or don't want to sort out the leakage problems then you will probably end up with an environmentally unfriendly system that will be able to heat your poorly insulated house just like millions of homes in this country. I think there is a word for one of these systems, it's called gas. The worst choice system however would be electric storage, apparently it can cost up to £100 per month......but I am definitely not recommending that.

They will both use the same amount of energy unless the rads are on the outside walls :-)

If the outside temperatures were so low that the radiators were unable to get the house hot enough (unlikely) then the test fails but rads are cheaper cos u r cold

Posted By: tonyThey will both use the same amount of energy unless the rads are on the outside walls :-)

I don't think so. My theory is that a heat pump that is cycled on/off frequently (in response to radiator/thermostat demand) will use more power than one that is cycled on/off only once in a 24 hour period even when generating the same amount of heat into the living space.

Also that for an equivalent 'perceived' level of warmth (comfort) a house with radiators will need to be run at a higher temperature compared to one with UFH.

SAP will not tell you about rad sizes. You need to calculate the heat loss for each area (room) and size the radiator approriately. The lower the flow temperature of you supply then the larger the radiator will need to be. Remember that radiators are normally calculated for 50 C flow temp and -3 C outside Rads are always bigger than needed most of the time. If i were you I would try it with the rads you have and see if it works -- it most probably will.

Posted By: ted

Posted By: moogaloo... new funky radiators that work with lower heat water ...

I'd love to see the technical spec for one.

Now I am not advocating these, just throwing them into the mix. They might be the bees nees or the new multi-foil I have no idea

http://www.jaga.be/lab.aspx?REP=0&ID=1

Hi Mark, can't see your email, the system is going in now in a new house, the system is Daikin split system air source.
The installer is Jack Elam Services, Spaceair also install Daikin but they charge a lot more for the same thing. Maybe contact Daikin directly for a local installer.


We were going to have a gas boiler and solar hot water with cylinder, but did away with both of these and installed the heat pump plus cylinder which cost less. Supply amd install of the heat pump was £4300 (but add to that rads or UFC etc).

If your house is poorly insulated you will need to either sort this out or oversize the oversized rads.

Posted By: liberteeen
You can insulate your roof using a double layer of triso super 10 stapled to the underside of the rafters as additional to any fibreglass quilt you may have on the floor in the loft.

You are possibly tempting the wrath of the anti-multifoil birgade here, recommending the thing stuff ;-)

I am not sure using a double layer of tri iso 10 over a single layer gives much more benefit, as multifoil primarily stops heat escaping by convection and reflection. If you do go the multi-foil route you would be better off putting some kingspan/ecotherm/celotex between the rafters (keeping a 50mm air gap) and putting the multifoil over the top of that.

It is probably best to speak directly Triso or Thinsulex? about the effect of multilayering, noone seems to know exactly why it works otherwise building regs would not have withdrawn approval. Although those who have used it including some personal contacts of mine seem happy enough with it as well as NASA who invented it.

There are plenty of ways to reinsulate houses from very simple up to a virtual rebuild. Cutting Celotext between the rafters is another option but depending on the amount of variation from a standard rafter width, at dormers, hips etc, it can take a skilled sculptor to cut it well and not leave gaps everywhere. We have just used Xtratherm Rafter lock which comes in a concertina type board 1200x600mm which compresses up to 30mm widthways. It worked a treat where rafters were at 600cc but was a real headache epecially where there were non rectangular sections at the hip. The contractor ended up paying carpenters to do all these difficult cuts. We could have put up 4 layers of Triso for the cost in time it took to cut between rafters.

Moog, I don't really disagree with what you are saying, I think reflectivity is part of it, but I would have thought that the numerous layers within the blanket are a bit like micro wetsuits, each layer holds a small amount of slightly warmed air. A colleague used a double layer recently on a fussy roof.

In truth I don't know I'd need a laboratory to give an exact answer.