Heat pumps

[bixy]

I was wondering if anyone has had experience of a heat pump [pompe a chaleur aerothermique]. We are on the point of deciding on a heating system and can choose anything, within reasonable cost, except town gas. I'm particularly interested in heat pumps, not just because of the alleged efficiency, but also because of the circulation of air which might help our condensation/damp problem. also I believe they can be used as air conditioners. Any views/experience?

Patrick

[Bob T]

Yes I have one in the bedroom. It heats, cools and is a de-humidifier. It has turned out to be very economical and claims around 3.3 kw of heat or cool for 1 kw input. I fitted it last summer and it is great. The only bad bit is that it is a little noisy.

[Gyn_Paul]

It rather depends on what your walls are made of.

I had no recourse but to mount the halves of a split-pack on either side of a breeze-block bedroom wall, so there is a fair amount of noise. The interior unit is not much worse than a fan-on-a-stick, but the outside part is more like a fan-plus-a-fridge. Had the walls been solid stone it would have been much quieter.

If you could arrange for the exterior part to be sited at ground level, and mounted on a concrete base rather than attached to the house wall, then I think you'd find the noise level inside the house to be negligable.

p

[Deimos]

I had some experts round a few years ago to advise on environmentally friendly energy systems I could consider.  One of their thoughts was aerothermal heat pump - though they were talking about the type that extracts heat into a wet system and heats domestic hot water and central heating systems.  anyway, their comments were that it works well even in cold external temperatures unless the air is moist.  Basically they do not work well in mist and fog (damp conditions) so if you are in such an area they might not achieve the performance you might hope for.

I am no expert and am just repeating what there experts said (a local ADEME approved plumber brought them in as he was new to such technologies and it was a learning curve for him as well - thus they were not the "install anything we can get the customer to pay for" types of people as they were basically advising the plumber as well).

Ian

[bixy]

Thanks for those replies. I hadn't realised until now that you can actually buy and fit these things yourself. What I would like to know is how easy/difficult it is to fit them. We have stone walls two feet thick. If I cannot fit it myself, who would I get to install it - plumber, electrician - both?

Patrick

[Gyn_Paul]

[quote user="bixy"]Thanks for those replies. I hadn't realised until now that you can actually buy and fit these things yourself. What I would like to know is how easy/difficult it is to fit them. We have stone walls two feet thick. If I cannot fit it myself, who would I get to install it - plumber, electrician - both?

Patrick

[/quote]

Are you a French (tax) resident? It's possible you would get some money back on such an installation. Have a word with your tax man and see if, in your area, you would qualify.

It would have to be fitted by an artisan, however. If you buy it and put it in yourself you WON'T qualify for a rebate. 

I'm about to enquire with my local tax man if I would qualify for such if my builder (a French registered mason) bought (ie. on one of his trade accounts) and installed an under floor 'wet' heating system for me. I'll keep you posted.

p

[bixy]

Thanks for that. Yes, that's a good point. Heat pumps count as renewable energy and are eligible for a tax credit of 50 % on the cost of the pump.

Patrick

[Le Plombier]

If you are looking to heat your whole house geothermie is a better option

You don't have the noise issues as you do with the aerothermie condensor fans and you generally get a more consistent COP which gives better economy on running costs

Le Plombier

[Caussenarde]

Heat pumps for domestic heating do attract tax rebates.

But I think you will find that air-conditioning units, which are reversible and so can heat the interior as well as cool it, do not......

[Mikew]

Reversible units attract tax rebates provided that they have a high enough COP (coefficient of performance) Our air/air units meet the requirements, are very effective and have cut down on the use of oil. The outside units are virtually silent.

[woolybananasbrother]

What is the name of these units please? Would they maintain a bedroom at, say, a steady 17 degrees C in winter?

[Gyn_Paul]

[quote user="Mikew"]Reversible units attract tax rebates provided that they have a high enough COP (coefficient of performance) Our air/air units meet the requirements, are very effective and have cut down on the use of oil. The outside units are virtually silent.[/quote]

Do you find the efficiency falls off at all as the o/s temp gets towards zero ?

p

[Gyn_Paul]

[quote user="Mikew"]Reversible units attract tax rebates provided that they have a high enough COP (coefficient of performance) Our air/air units meet the requirements, are very effective and have cut down on the use of oil. The outside units are virtually silent.[/quote]

Do you find the efficiency falls off at all as the o/s temp gets towards zero ?

p

[Gyn_Paul]

[quote user="Le Plombier"]

If you are looking to heat your whole house geothermie is a better option

You don't have the noise issues as you do with the aerothermie condensor fans and you generally get a more consistent COP which gives better economy on running costs

Le Plombier

[/quote]

Yes, but you're also looking at h-u-g-e capital costs for either bore holes or trenching for the pipework.

My big beef for the whole idea is - yes  - you can get as much as 4 kw heat for every 1kw of electricity used (if you're lucky) but in order to do it, you are on a high current tarrif, which means a high cost abonnement.

Now if only EDF would allow a discount for geothermie installations, it would start to make sense.

p

[Le Plombier]

The comment on electricity costs apply equally to aerothermie

Whilst geothermie is more expensive it is a much better solution than aerothermie and more cost effective to run

My previous comments were aimed at heating an entire property, not a single room

With both systems you can have ducted air, via an air handling unit or a wet piped system giving both heating and cooling

Le Plombier

[Poolguy]

I would suggest that in conjunction with a heat pump or sole other selectable source that you look at evacuated tube solar array as this will continue to harvest heat even in sub zero tems, so long as there is light radiation around.

Its simple and very effective especially for domestic hot water.

 

PM me if you want more details.

 

Andrew