Air Source Heat Pumps

albyota · 14 November 2009 at 4:27PM

eugeneg wrote: »

I have an 11KW NIBE ASHP installed in a 3 bed detached house. The NIBE rep came around and suggested that I insulate underneath the suspended wooden ground floor before the new carpets go down. Is this OTT ?
A possible insulator to push up between the joists may be [FONT=&quot]wickes.co.uk/Easy-Fit-Insulation-Board/invt/210020 [/FONT]

As with any heating system, Insulation against the cold is the best advice to be given, the Nibe rep will have been trained properly, therefore to just sell these energy efficient products without giving well researched advice, he would not be doing his job right. as for OTT... why would you spend your hard earnt on this type of energy efficient system and then let the heat escape through drafty floors (or allow the cold draft in, cooling what you are trying to heat). hence good advice from the nibe rep.

eugeneg · 14 November 2009 at 4:37PM

Albyota, thanks for the reply. I'm convinced that insulation is good, but with thick new carpets down I wonder how long it would be before the £1000 (a guess) in insulation would be made up by lower energy consumption bills.

albyota · 14 November 2009 at 4:46PM

Cardew wrote: »

Much as the discussion on problems with your ASHP is interesting, and indeed helpful, I fear it may put many people off ASHPs.

The majority of people want a 'switch on and forget' CH system and it appears that to get the ASHP system operating efficiently, you need a lot more than a layman's knowledge!!

It must be distinguised here what sort of ASHP is being discussed, it would be helpful if there was a separate Air to Water Heat Pump section which are to the 'layman', fit and forget CH systems....if installed correctly. I agree with cardew in that, the discussion on air to air heat pumps (standard air conditioning, which provides heating and cooling), are between a few people trying to get optimum performance from their systems and who are in the industry and I also find it interesting, but is it actually moving away from the money saving aspect? no offence andy, steve, richard, chippy etc, I am in the industry as well, maybe we could get back onto the running cost saving advantages from fitting Heat Pumps....Air to Air and Air to Water systems.;)

albyota · 14 November 2009 at 5:02PM

eugeneg wrote: »

Albyota, thanks for the reply. I'm convinced that insulation is good, but with thick new carpets down I wonder how long it would be before the £1000 (a guess) in insulation would be made up by lower energy consumption bills.

The problem is, just fitting thick carpets which will, 'Soak up' the cold damp air, they will eventually start to smell and will always be a cold surface, the void beneath the floor was designed to allow the timbers to breath, and before doing anything, you should investigate whether insulating under there is likely to cause further problems in the future, but vapour barriers, thermal bridging, ventilation etc.. should be researched/considered first.

eugeneg · 14 November 2009 at 5:14PM

albyota wrote: »

before doing anything, you should investigate whether insulating under there is likely to cause further problems in the future, but vapour barriers, thermal bridging, ventilation etc.. should be researched/considered first.

Gosh - have I bitten off more than I can chew ? Where can I research these things ? I'm not in the heating/plumbing/insulating business and am as thick as two short planks. Perhaps I could get definitions for the terms easy enough, but I can't think where to find the pros & cons of each type of insullation. I imagine they all allow 'breathing' so the floor boards should be ok, but to be on the safe side perhaps in this case it is better to not insulate.

albyota · 14 November 2009 at 5:28PM

no, sorry I didn,t mean to scare the bejasus out of you, it all depends on the age/type of house and construction, a breathable type membrane is probably all you need, which will stop the drafts, advice is free, but it is better to get several opinions from the insulation companies and decent builders before the next stage, of either fitting carpets or spending money on the wrong thing.

Side · 18 November 2009 at 6:43PM

eugeneg wrote: »

I have an 11KW NIBE ASHP installed in a 3 bed detached house. The NIBE rep came around and suggested that I insulate underneath the suspended wooden ground floor before the new carpets go down. Is this OTT ?
A possible insulator to push up between the joists may be [FONT=&quot]wickes.co.uk/Easy-Fit-Insulation-Board/invt/210020 [/FONT]

Obviously the more insulation you put in the better, but are you having problems with the heat pump not achiving target temperature in the living space? A three bed house built to todays regulations should only require between 3 and 5 KW of heat energy @ 21 deg C/-3 deg C.

If you do 2 x heat loss calculations, one with the floor insulation and one without you can work out how much energy it will save you and estimate how long the insulation will take to pay for itself. If you want to send me the details of the house I can have a look at the calcs for you?

eugeneg · 18 November 2009 at 8:42PM

Thanks Side. Although the ASHP is probably over specified for a 3 bed house, there are loose plans to extend the loft to make a 5 bed house (hence, the poor insulatin up there). Also, the house is 110 years old so not as well insulated as modern ones. I'm not sure how heat loss calculations work - what the parameters or function would be.

The walls have no cavity and half have 200mm internal insulation. All windows double glazed. Roof currently only about 300mm fibre. Not sure what else to say really.

Fire_Fox · 19 November 2009 at 2:50PM

Why don't you just insulate the loft properly? It's not expensive and, depending what you choose, you can reuse the lagging if you end up having an extension. Heat rises so presumably you are expecting your system to heat half the street!