It is currently 29 Mar 2024, 01:03
RogerS wrote:I love this sentence
Windows for a semi-detached house that are A-rated, taking in as much heat as they let out, would cost about £4,250, with energy bill savings of about £75 per year.
Confirming what we've known all along that the cost-benefit case for double-glazing is pretty dire.
RogerS wrote:The other thing that they've skated over is that, with a heat pump, you will need to put in either underfloor heating or replace all your radiators with much larger ones! They leave the cost of that out of the figures !
Just4fun wrote:RogerS wrote:The other thing that they've skated over is that, with a heat pump, you will need to put in either underfloor heating or replace all your radiators with much larger ones! They leave the cost of that out of the figures !
Maybe, maybe not. It depends on the existing system. When we replaced our oil burner with a GSHP we didn't need to change radiators or anything else, we just put in the heat pump.
Just4fun wrote:RogerS wrote:The other thing that they've skated over is that, with a heat pump, you will need to put in either underfloor heating or replace all your radiators with much larger ones! They leave the cost of that out of the figures !
Maybe, maybe not. It depends on the existing system. When we replaced our oil burner with a GSHP we didn't need to change radiators or anything else, we just put in the heat pump.
Lurker wrote:I may be wrong, but hasn’t Finland got a very efficient hydroelectric scheme making your electricity both cheap and reliable
RogerS wrote:Far as ground source heat pumps are concerned most people think about a large footprint of pipes horizontal.
At our last place, the guy across the road produced a really good spreadsheet (sadly I have lost my copy) that looked at the CBA for virtually every conceivable alternative. In the end he settled for a vertical borehole.
AJB Temple wrote:Am still thinking about a pellet burner system.
Andyp wrote:How wide does a vertical bore hole need to be?
Andyp wrote:I think on the vid he was using what looks like 40mm pipe and went down 40 metres. I'll not be trying it any time soon.
RogerM wrote:It sounds like a lot of us are going through the same thought process. I live in a 1970's "box" which has some polystyrene sheet cavity wall insulation, and 250mm of fibreglass mat in the loft. Apart from our kitchen extension, there is no insulation in the solid floors, so UFH is not an option.
My reading up on air source heat pumps leads me to conclude that they can be noisy, and if the outside air temperature drops to 5C or below, they become increasingly less effective and use exponentially more power. Then there is the need to site them outside where they are open to the elements, as well as thieves who will be looking for something else to nick as catalytic converters become less common with the advent of electric cars. The wear and tear from the elements is much greater in coastal locations due to the salt content in the air. Although we are 1/2 mile from the sea, our windowns get covered in salt after a south-westerly storm.
Ground source heat pumps are more costly to install, but are sited inside the house so do not suffer from the elements or risk of theft. They are smaller, and considerably quieter, than their air-source brethren - no more than an average dishwasher. We have 1/2 acre of garden, including a large lawn which would probably be large enough for a shallow "slinky" array. However, I have read that a deep borehole will be much more efficient as the temperature of the ground 100m below the surface is remarkably stable at around 12C even through the hardest winter. A bore hole does add about £8k to the installation cost though, although it doesn't mean trashing your garden in the same way as a shallow array does. I suspect that there will be a law of diminishing returns here though, and suspect that in the southwest, the extra efficiency of a bore hole over a shallow "slinky" array would be marginal.
With a 10 year old Worcester-Bosch oil-fired condensing boiler, our maintenance engineer reckons it should last at least another 10 years with regular servicing. His firm also does Heat Pump installations, and when i told him we were in no hurry to convert, his reply was "Very wise. Hang on to this one as long as you can".
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