Energy Matters Global and Domestic

[bobins]

Whilst they are incredibly efficient at turning electricity into heat, there are still drawbacks. Cost of purchase and install is - obviously - one, but they also struggle to put out hot water at a heat comparable to a gas boiler which can be an issue if you plan to use one in conjunction with existing radiators. Ideally you'd need to replace existing rads with higher BTU ones to compensate for the lower output temp of the heat pump or change over your house to use, effectively, a heat pump as an aircon unit.
As a ball-park comparison which may or may not be relevant, I replaced my gas boiler at the start of the year with a new efficient one and that, along with other upgrades and bits and bobs cost £1400-£1500 all-in.

[NewcastleFalcon]

Aren't they supposed to be so much more efficient than traditional heat production that it more than compensates for the greater price? From the depths of my addled brain I seem to remember that they use a third less electricity than if the electricity were used to simply produce heat.

That probably makes it about equal to burning mains gas I suppose. The devil may be in the detail of course. These are just figures worked out on a used Kleenex.

Thats about it Paul, there is a sister thread to this which filled 6 pages on the subject of Heat pumps from the FCF's finest brains! Simple vid from it to refresh our memories

viewtopic.php?t=68305&hilit=heat+pumps

Regards Neil

[Paul-R]

Just a slight correction. I meant to write "they use a third of the electricity" instead of "they use a third less electricity".

[myglaren]

I think we may all be constructing these for the winter

[Peter.N.]

A ground source heat pump may give you three times as much heat per Kwh but at current electricity prices that still works more per Kwh than gas or even oil. An air source heat pump is not that efficient, I know we have one that we no longer use. When it was working it did indeed give possibly three times as much heat as the equivalent power consumption until the temperature got down to freezing then it was down to about 1 to 1.

A well installed ground source pump will give better savings providing that the evaporator can maintain a constantly warmer supply of air/water if it doesn't collect it over a large enough surface you can end up with permafrost which will give the same result as an air source pump.

It works on the same principle as e refrigerator which cools the air in the fridge by moving the heat from inside the to the condenser on the back round the system, its a refrigerator in reverse. The compressor compresses the gas in the system which is then cooled by the condenser in to a liquid it is then fed into the evaporator in the fridge where the pressure is considerably reduced which causes it to evaporate become very cold and and cool the fridge.

The basic refrigeration process can be demonstrated by wetting your hands with a volatile liquid like methylated sprit and waving them about, they feel cold as the spirit evaporates which requires heat so it takes it from your hand. The same thing happens when you get out of the bath only with water of course.

Peter

[Gibbo2286]

I'm still on the deep thought section about the solar storage Mick, enquiries to companies claiming to be battery suppliers get no response...................and I'm too old to spend seven grand on a heat pump.

[Peter.N.]

There were quite a few ex standby batteries for sale on Ebay - or there were, a lot seem to have dissapeared now. 12v about 150ah for around £100-150 worth a look but you need a proper car battery load tester to check them.
https://www.ebay.co.uk/itm/113876928960 ... R7ah28T3YA
Peter

[Gibbo2286]

I need a proper Lithium battery set up Peter I don't have the necessary enthusiasm to do it myself nowadays.
I do have this battery tester that was given to me by my workmates when I set up in my own business back in 1965. A bit out of date now.

[mickthemaverick]

Have you seen these Gibbo?

https://www.ebay.co.uk/itm/114401704687 ... R-6lss_3YA

[Peter.N.]

Did the job just as well though Gibbo. I'm afraid im not in the lithium financial league.

Quite a few about now Mick, don't seem to be getting much cheaper though - except in America.

Peter

[Gibbo2286]

Yes I've seen those Mick they pop up every time I do a solar battery search but I really want a set up that does the mains back up in power outages and works in the evenings when the sun goes down.
Need a suitable supplier to instal it into my system. I think Neil has posted some examples on video.

[Paul-R]

There's another twist on working out the cost/benefit ratio making gas more expensive as of the first of October. On that date the increase in the gas rate went up by 40% whilst the electricity rate went up by 20%, thus reducing the advantage gas has for heating and cooking. The standing charges went up by between 1% and 5% on the same date. There's still a straightforward advantage for gas but the gap has narrowed a bit. How that now compares with a heat pump I don't know.

The mention of the standing charge shows another possible saving but it's quite radical. My brother uses a miniscule amount of gas. The gas boiler burst a pipe in a freeze some ten or more years ago and has been disused since leaving just a gas hob in use (the oven/grill hasn't worked for years). For a long time he went on to a rate where there was no standing charge but quite a high unit rate. His bill was still less than £5 a month!

When the no standing charge rates were all withdrawn we looked into having the gas meter removed or capped off and it was something like £90 odd and, as his monthly cost had gone up to something like £10 a month but that included his cooking, was eventually decided against. Now we're not so sure.

For the last six months he's had the gas turned off as he was supposed to be having a smart meter fitted and he prepared for that. It's remained switched off and he's been cooking/heating on a small LPG camping burner since. He's already installed an LPG heater in his bedroom so he's not getting cold.

[mickthemaverick]

I found Dave's offering this week on Just Have a Think to be a good summary of where we are in our global cleanup path:

[myglaren]

Apologies for the annoying commercial.
At least this American is quiet and tolerable.

[myglaren]