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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> Heat Pumps - What do you think? https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1379666995 Message started by mountainman on Sep 20^th, 2013, 9:49am

Title: Heat Pumps - What do you think?
Post by mountainman on Sep 20^th, 2013, 9:49am

Hi guys, reasonably new here and just wanted to get your opinions on these: http://www.bsw-bs.co.uk/latest-news/2013/06/heat-pumps-save-you-money/

I've been doing abit of research and they look pretty promising!
Let me know what you think? ;D

Cheers

Title: Re: Heat Pumps - What do you think?
Post by big_all on Sep 20^th, 2013, 11:55am

if you have mains gas you are already 300% more efficient as a kw off gas is around 1/3 the price off a unit off electricity
the savings with gas can be minimal and a badly specked or badly set up system will cost you more indeed your energy bill can double or triple if you get it wrong :-/ :-/

and because electricity prices follow gas up rising gas prices do not mean any real savings

Title: Re: Heat Pumps - What do you think?
Post by CWatters on Sep 20^th, 2013, 7:52pm

What Big_all said. There is a good comparison site here...

http://www.nottenergy.com/energy_cost_comparison

The most important figures in their table are those in the column labelled "Pence per kWh (after boiler efficiency)". This takes into account the efficiency of a gas boiler or the COP of a heat pump.

They suggest that as of July 2013 mains gas is slightly cheaper than an ASHP but slightly more expensive than a GSHP.

I once asked them about the assumptions they made in compiling the data and they told me that the figures for a heat pump also assumed it was connected to a low temperature heating system (eg Under Floor Heating or oversize rads).

There is some evidence that heat pumps are not suitable as drop in replacements for a gas boiler, particularly in large badly/average insulated houses with small/standard size rads.

It's also very important to get the size of heat pump right. Many contain a booster coil (COP =1) which is used when it's very cold outside. If the heat pump is undersize then the booster coil is used a lot more and bills quickly rocket as that's a bit like having direct electric heating. So important to get a good installer to do the heat loss calculations.

Overall I reckon if you were building a new very well insulated house, with UFH then a ASHP/GSHP would be worth considering. If you live in an ordinary house built say 15 years ago I would probably stick with mains gas or oil (kerosene) if mains gas isn't available. It might be a different matter if you also had a large solar PV array.

Title: Re: Heat Pumps - What do you think?
Post by big_all on Sep 22^nd, 2013, 1:51am

http://www.bbc.co.uk/iplayer/episode/b03bklsj/Rip_Off_Britain_Series_5_Episode_12/