air source heat pumps pros and cons

[Big J]

Totally agree with insulate,insulate,insulate.

 

"They are however a very inefficient method of heating your home or your hot water. You cite summer usage for hot water, but you would be far better (and it would be much cheaper too) to install solar hot water panels. "

 

Sorry Jonathan can't agree with all of this unless you think 1.7 kWh per day for hot water is expensive. Don't get me wrong solar hot water is very good but almost impossible to do all your space heating with so you then need another system for space heating. The great thing with heat pumps, air and ground sourced is they are capable of doing both from one unit. It would be great if we could all live in Passive houses with no need for heating systems but it's not going to happen in the near future and a well designed heat pump systems is a good solution for some. Today for example I have turned on our GSHP as it running for free with the electricity generated by our solar panels. Recently we added a wood burner not because we were cold but because we were selling logs and it made sense to use them for some of the heating. I did some figures and worked out we would be better off just running the GSHP and selling all the logs. We haven't chosen to because we love the flames from the fire but the figures were clear cut. Heat pumps are not a fix all solution for everyone but a well designed system in a well insulated home is capable of a COP of 4 and that is cheaper to run than mains gas.

 

Glad to hear that your system is working well for you, but the fact of the matter is that they aren't the best way to improve your house's energy efficiency.

 

Firstly, you have PVs running your units, which is in itself unsustainable. Small scale PV systems are uneconomical, and almost no one would have them in this country if it weren't for the huge grants (that have now mostly expired, mercifully) and high FITS payments. Without subsidy, PVs degrade to the point of being useless before they have paid themselves back in this country.

 

Secondly, there is a big problem in this country with focus on 'eco bling' (small scale renewables) rather than high levels of insulation. The building regs still have very poor U-value targets, yet all new houses must now have some form of carbon offset, which means the inevitable addition of a decorative windmill or solar panel. It's environmental tokenism and is misguided.

 

Here is a link to a book written by my wife's boss which expands on the above quite considerably:

 

[ame=http://www.amazon.co.uk/Ecominimalism-Antidote-Eco-bling-Howard-Liddell/dp/1859463002]Ecominimalism: The Antidote to Eco-bling: Amazon.co.uk: Howard Liddell: Books[/ame]

[NI Tree]

i agree with big john i about the problem,

for example why not make it the cavity in cavity walls larger for more insulation as what is the extra cost of doing for the gained insulation in the long run. the problem is buliders are in the game for short term gain so do the minimum they can get a way with, for the lowest cost, and most profit,

Edited February 11, 2013 by NI Tree

[Big J]

i agree with big john i about the problem,

for example why not make it the cavity in cavity walls larger for more insulation as what is the extra cost of doing for the gained insulation in the long run. the problem is buliders are in the game for short term gain so do the minimum they can get a way with, for the lowest cost, and most profit,

 

The problem is the building industry here full stop. People don't want to take responsibility for building their own houses, so developers build almost all new housing here. Consequently we hugely overpay for crappy quality housing with at most a 50 year life expectancy. We endure tiny plots, tiny rooms, next to no sound insulation and cramped developments.

 

From the BBC news website:

 

"Other countries are way ahead, he says. In Austria 80% of all homes are self-built. In Germany, France and Italy the figure is 60%. In the US and Australia it is over 40%. By contrast the figure for the UK is about 10%."

 

The article in question: BBC News - Self-build: Should people build their own homes?

 

What is needed is a fairly monumental shift in national mindset coupled with government action to effectively put most developers out of business. Also, all planners should be hung drawn and quartered, just to be sure!

[NI Tree]

The problem is the building industry here full stop. People don't want to take responsibility for building their own houses, so developers build almost all new housing here. Consequently we hugely overpay for crappy quality housing with at most a 50 year life expectancy. We endure tiny plots, tiny rooms, next to no sound insulation and cramped developments.

 

From the BBC news website:

 

"Other countries are way ahead, he says. In Austria 80% of all homes are self-built. In Germany, France and Italy the figure is 60%. In the US and Australia it is over 40%. By contrast the figure for the UK is about 10%."

 

The article in question: BBC News - Self-build: Should people build their own homes?

 

What is needed is a fairly monumental shift in national mindset coupled with government action to effectively put most developers out of business. Also, all planners should be hung drawn and quartered, just to be sure!

 

well said

[woodland dweller]

Hi all, thanks for all the input regards heat pumps, i have shown my friend all the responces and it has helped. He is having solar panels and a wood burner fitted as well as the heat pump. Yes the house has loft and wall insulation and double glazed windows so it should work well. Although at the moment the place has been empty for 3 years, i a'm doing a complete refurb its bloody cold inside. Insulation is great if you can have it but my 400 year old cottage has no cavity to insulate and the half that is thatch has no loft. The single glazed windows are well drafty. No heating except the 2 wood burners, luckily the fire wood is free. At moment a new build sounds nice, roll on summer.