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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
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  1.  
    I am starting to think about how rental refurbishments can be done so as to exclude gas from the property.

    A refurb of a "Little Brown Bungalow" I have just done with GFCH was discussed here (*) and more extensively over on Buildhub. That achieved an EPC rating of approx C76 by doing the normal things with attention to detail. Gas/elec is forecast to be about £500 per year, which is OK if not brilliant.

    I am trying to get a handle on how good a property needs to be insulation-wise etc to be a realistic prospect for the installation of an ASHP plus UFH and a suitable Plan B Top-Up/Backup for when the ASHP breaks or it is too cold for good efficiency. For a rented property it needs to be as maintenance-free as possible, simple to use, robust and able to be comfortable and inexpensive for the T in all circumstances, while giving me an EPC figure at least good enough for the regulations (which means C or above).

    Any comments would be welcome.

    Cheers. Ferdinand

    (*) http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14711
  2.  
    Heating source and insulation efficiency are not related. The only question you need to ask is: do I have sufficient capacity to meet the heat load at the target temperature (with back-up, as appropriate). Any increase in insulation level will help all forms of heating. I'm not sure if they are available in the UK, but several Asian manufacturers make "cold climate" ASHPs.

    Paul in Montreal.
    • CommentAuthorGarethC
    • CommentTimeDec 11th 2017 edited
     
    I don't understand why a heat pump needs better thermal efficiency at all, so long as the heat pump is correctly sized for the heat demand and the emitters are big enough (unless a room's heat demand was so bad that the radiators would have to be the size of the wall to work efficiently).

    Also, it's as cold round here as I can remember it getting (Edinburgh, min temp of -3) and every modern ASHP I look at suggests it would cope with that just fine. Swedish tests showed they were OK at much lower temps than this.

    So basically I'm interested too!

    Crossed over with Paul's post and it sounds like his experience is in line with my expectations!
    • CommentAuthorDarylP
    • CommentTimeDec 11th 2017
     
    @ferdinand, model the dwelling with an ASHP and as much insulation/thermal envelope upgrades that you can reasonably assume
    then
    compare that with the same dwelling but with GCH.....
    Good luck:smile:
  3.  
    Cheers so far.

    @Paul

    I am thinking about cost for the T as well as capacity.

    My perception is that if something is not right, or say the conditions are cold, the cost of using a lot of extra electricity to power an ASHP running at a low CoP (*) are much more significant than the cost of running a gas boiler at full chat - since peak Elec costs far more than Gas per kWh. So in that circumstance a Gas Boiler is far more resilient form the point of view of extra costs imposed on the T - hence my desire to reduce that potential by a better fabric standard.

    Several years ago there was something of a scandal here about the cost of running Heat Pumps. "Not enough insulation" is quoted as a cause. That is one of the things I need to have worked through. Perhaps it is an "exhaust air source heat pump" vs "air source heat pump" question.

    eg http://www.bbc.co.uk/news/business-19511637

    Storage heaters and E7 might sounds attractive, but they slug the EPC figure and that is now regulated under penalty and the goalposts move every few years, plus the HHSRS regulations can treat them as a Health Hazard on grounds of "lack of flexibilty", and Local Authority Enforcement Officers do not necesarily have the skills needed to run HHSRS properly.

    Ferdinand

    (*) eg http://info.cat.org.uk/questions/heatpumps/how-can-i-ensure-air-source-heat-pump-ashp-efficient/
  4.  
    <blockquote><cite>Posted By: DarylP</cite>@ferdinand, model the dwelling with an ASHP and as much insulation/thermal envelope upgrades that you can reasonably assume
    then
    compare that with the same dwelling but with GCH.....
    Good luck<img src="/newforum/extensions/Vanillacons/smilies/standard/smile.gif" alt=":smile:" title=":smile:"></img></blockquote>

    Cheers.

    That is indeed part of the plan.

    Fortunately I have a gas-powered one I prepared earlier, and hence some empirical data in a few months.
    • CommentAuthorGarethC
    • CommentTimeDec 11th 2017 edited
     
    Well, heating a home with an ASHP on the (very) odd occasion when it is -7 degrees will be more expensive than with gas at the same time, as the COP falls. But on average (especially if the ASHP only does space heating, not COP killing DHW), if the ASHP is well specified, you should achieve an SPF over the year of about 3 (I'll dig out the latest EST field results. The ones in your link relate to an older study).

    That would make it about the same cost as heating by gas on average, as leccy's about three times the price. Not cheaper I'm afraid, but should be greener.

    What impact would an ASHP have on EPC vs gas heating? Struggling to get my mind around that. Do they assume an SPF in the calculation? And if so, presume it must change as the UK's electricity generation mix does... Seems a complex question to me. Anyone know?
    • CommentAuthorjerseyman
    • CommentTimeDec 11th 2017
     
    I have an air-to-air ASHP at our minimally insulated place in Spain, when it is -2 the output is pretty minimal, but the main issue for me is that, with a wall mounted unit, the output seems to contain more draught than heat. If you walk into the room it is warm enough, but sitting in it is not comfortable. Caveat, my units are about 8 years old modern ones may be much better.
    •  
      CommentAuthorSteamyTea
    • CommentTimeDec 11th 2017
     
    When doing a heat loss calculation for an RHI installation, MCS need a '99% of the time' calculation.
    So all you have to do is the room by room heat loss sums, then work out from local weather data how often the 1% is.
    Pretty easy to do as external temperature is pretty evenly distributed.
    As long as you remember that different heat pumps have different characteristics i.e. when most likely to frost up, then you can work out the sizing. You need some detailed manufactures data for that bit.
    • CommentAuthorRick_M
    • CommentTimeDec 12th 2017
     
    Posted By: GarethCThat would make it about the same cost as heating by gas on average, as leccy's about three times the price. Not cheaper I'm afraid, but should be greener.


    Would there be savings in the long run, does an ASHP have lower maintenance and replacement costs compared to a gas boiler powered system?
  5.  
    Alongside the comments above there is an underlying story. Gas appliances in rented property in the UK require annual maintenance and periodical certification which are a pain for landlords. However gas central heating is a plus point for potential tenants and electric heating whilst easier for landlords is seen as expensive by tenants. So landlords want electric heating, but this is a hard sell for tenants and tenants want GCH which is a pain for landlords. Can someone square this circle?
    • CommentAuthorgravelld
    • CommentTimeDec 12th 2017
     
    It's essentially a broken system; tenants want comfort, they shouldn't want a particular energy source. They only know about the energy source because certain choices derive unsatisfactory results for them.

    However, we're now locked into this situation as the norm, and few people take a step back to ask why. That's probably because those same people are too busy trying to get food on the table.

    If anything squares the circle, it will be with an enormous investment to begin to build and fix houses as the products they should be. They should "just work".
    • CommentAuthorGarethC
    • CommentTimeDec 13th 2017 edited
     
    Posted By: Rick_M
    Posted By: GarethCThat would make it about the same cost as heating by gas on average, as leccy's about three times the price. Not cheaper I'm afraid, but should be greener.


    Would there be savings in the long run, does an ASHP have lower maintenance and replacement costs compared to a gas boiler powered system?


    I've thought about this a lot. I'm still not sure (I haven't been able to get one yet due to planning restrictions). Can anyone else advise from experience?

    Long story short, I think there should be some -operating cost- savings over gas IF the ASHP is well specified and installed (i.e. it gets an SPF of 3, which latest government field trials suggest is entirely possible), but I just don't think they'd be much.

    In principle, if it lets a household go 'gas free', there should be savings on not even having to pay a gas standing charge. But on the other hand, I think there's a charge for cutting off the gas supply, and I'm not sure how much that is.

    Then, the outdoor unit does need to be serviced periodically, although probably not as often as a gas boiler.

    The killer is the capital cost. Replacing a gas boiler with an ASHP just costs too much, even though they're increasingly much greener than GCH.

    But of course that's exactly why there are currently generous subsidies to offset the big installation cost. I just hope the capital cost comes down such that heat pumps become a bigger market, but there's a long way to go I think.
  6.  
    Our ashp has a warranty and one condition of it is we have to get it serviced every year. The 'service' is a basic check for leaks, clean some filters and the fan unit, check the safety valve. It costs about the same to get a service as did the oil fired boiler it replaced. So far, it has been much more reliable than the oil boiler with no breakdown callouts or costs.
    • CommentAuthortony
    • CommentTimeDec 13th 2017
     
    How often do people service fridges, they are heat pumps.
  7.  
    Not aware the one at my former place of work has been serviced in 11 years, but as WillInAberdeen says, servicing may be a requirement of a guarantee.
    •  
      CommentAuthordjh
    • CommentTimeDec 13th 2017
     
    Posted By: tonyHow often do people service fridges, they are heat pumps.

    Agreed but they don't have outdoor components, nor refrigerant pipes that are usually finished/sealed on site. A requirement for an annual service is still a major put-off for me though. I do religiously service our electric blanket every year though - but again I'd object if I was made to pay for it.
    • CommentAuthorGarethC
    • CommentTimeDec 14th 2017
     
    If this is correct, it should help answer the OP I think. It makes the point that to run with decent COPs (low flow temps), you need very big emitters unless thermal efficiency is fairly decent.

    Then, the question becomes 'how thermally efficient should the property be, such that emitters need not be unfeasibly large?'

    http://www.beama.org.uk/asset/53B96C5B-80B3-4B01-949A2AA8CA0F5C52/
    • CommentAuthorringi
    • CommentTimeDec 23rd 2017
     
    I have had too many tenants that can not understand that a thermostat is not an on/off switch to be turned when they feel cold. Hence UFH does not seem to be a good option.....
  8.  
    Thanks for all the comments.

    Planning to reply but have been busy.
  9.  
    Having looked around, the political environment seems to me to be quite likely to destroy any point in making investments in improving rental property for more than a very short time horizon, if that is not immediately reflected in the current market value.

    eg Corbyn's proposals in 2015 on a private sector Right to Buy after 3 years of a tenancy for properties more than 25 years old. If the value of renovations are not reflected in the value of the property, any investment for the long term is just throwing money away. They do not even seem to have published the results of their consultation, so God only knows what will happen.

    They do not seem to know whether they want a long-term regulated rental market, or a tenant's right to buy; the two are not compatible and the doubt makes long term investment impossible.

    I am not particularly convinced that the Tories will be much better, given Mr Osborne's antics - though at least that incentivises long-term investment.

    So I do not see any point in pursuing this conversation with respect to renovated properties, as it will not be worth the extra risk in any case at this time - just based on the politics.

    The future would seem to be in new build and renovations for "buy then sell" restricted to improvements that are recognised by the market now. I wonder who will do deep renovation on all the older properties that Councils sold off as not being economic to improve, or the long term empties?

    Anyhow, cheers for the input.

    Ferdinand
  10.  
    Posted By: ferdinand2000eg Corbyn's proposals in 2015 on a private sector Right to Buy after 3 years of a tenancy for properties more than 25 years old.

    Surely all that would do is to limit tenancy contracts to periods of 2 1/2 years max without the option of renewal.
  11.  
    Posted By: Peter_in_Hungary
    Posted By: ferdinand2000eg Corbyn's proposals in 2015 on a private sector Right to Buy after 3 years of a tenancy for properties more than 25 years old.

    Surely all that would do is to limit tenancy contracts to periods of 2 1/2 years max without the option of renewal.


    WHere it has been fleshed out eg by Civitas, another aspect is eg five year tenancies with restrictions specifically to prevent the RTB being undermined.

    I do not have a problem with longer tenancies or rent rises limited as per Germany etc, as that is simply what happens already as the norm in a more flexible framework. THey need to decide what they want, and flesh it out.
    • CommentAuthorArtiglio
    • CommentTimeDec 30th 2017
     
    Attacking private landlords is just seen as an easy way of making political capital, all the parties will do it, plus it covers up the atrocious lack of forward planning in respect of housing supply.
    The game is pretty much up for new entrants into the market , there appears to be scope if you wish to “build to rent” otherwise the sector is being reshaped to encourage the big institutional investors.
    With regard to energy efficiency in rented property, if you can achieve an honest d rating or better you’ll be well ahead of most private rented property and already represent good value to prospective tenants. Most however will have energy costs well down their list of priorities. Spending more of your own money to improve things will only bring additional personal satisfaction in the property you offer.
    HHSRS is in theory a good assessment tool but as you point out few local authorities use it properly and in a majority of cases cherry pick lines from it to prove a point, but when pressed for a proper full assessment cannot back up their claims. So long as any storage heaters in a property were capable of keeping it warm their affect on the property would be inconsequential in an HHSRS assessment.
  12.  
    https://scotland.shelter.org.uk/get_advice/advice_topics/renting_rights/renting_from_a_private_landlord/the_private_residential_tenancy

    On 1 December 2017 a new type of tenancy came into force [in Scotland], called the private residential tenancy, it replaced assured and short assured tenancy agreements for all new tenancies.

    What changes:

    No more fixed terms - private residential tenancies are open ended, meaning your landlord can't ask you to leave just because you've been in the property for 6 months as they can with a short assured tenancy.
    Rent increases - your rent can only be increased once every 12 months (with 3 months notice) and if you think the proposed increase is unfair you can refer it to a rent officer.
    Longer notice period - if you've lived in a property for longer than 6 months your landlord will have to give you at least 84 days notice to leave (unless you've broken a term in the tenany).
  13.  
    A Scottish private residential tenancy can only be ended by 1 of 3 ways:

    by a tenant giving notice and leaving or,
    the tenant and landlord reach an agreement to leave, or
    your landlord can prove certain conditions, such as they are selling the property, or misbehaviour or rent arrears by the tenant.
    • CommentAuthorgreenkeith
    • CommentTimeDec 30th 2017 edited
     
    We heat our 1975terraced house using a Mitsubishi heat pump. It was installed in Dec 2011. They quoted £158 pounds per year to service it. They also “ suggested “ that it had to be serviced to meet regulations. When I looked the regs up I realised that it didn’t. So for the last 6 years it has not been serviced at all except that from time to time I make sure that the air filters are clear. It has performed faultlessly. So much so that I have now had our gas supply capped off. Re insulation, I don’t think you can have too much. We have cavity wall plus some additional internal wall insulation . 300 mm of loft insulation. Basically as much as I could reasonably manage. Over the years our electricity consumption has falle n from about 18500kWh per year, to just over 5000 kWh. The heat pump is rated at 1kW but I think is runs at about half of that. It has performed at -7 degrees without problems. We used to have a gas fired back boiler rate at 11.5kW. Getting rid of that was the best thing I ever did.
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