Air source heat pump vs modern electric storage heater (Scotland)

123456

Sorry if this is in the wrong place or duplicate; I've done searches but can't find anything relevant to my query. We are 2 adults in a bungalow, been here 3 yrs. We have a 2 yr old wood burner which is our main source of heat and 20+ yrs old oil boiler which has just died.  We need to replace the boiler so we can have hot water but our needs are low as we have electric showers and do not use the bath. Most of our washing up is with cold water or just boil a kettle.  We are probably unusual in our heating/hot water needs as we like a warm living room at night, which the wood burner provides, but we have tended never to heat other rooms unless it is exceptionally cold.  For instance, I have worked at home for 6 years and have only rarely used supplemental heat (from a halogen heater close to me or occasionally the CH); instead I have layered up clothing to be warm.  When I worked in offices I was always the one who was too hot and wanted the window open. I feel the same in most people's houses! However, I am conscious that we are getting older (60 now) and our needs may change.  We want to "put our money where our mouth" is to be 'green' and we do try to live a low impact life in all ways.  However we have been quoted £12k for an air source heat pump system and (not withstanding possible grants/RHI which would reduce the cost to us) I am concerned that we would be installing a system that is over capacity for our needs and therefore intrinsically not environmentally sound.  We wonder if modern storage heaters which could be used more on-demand, and cheaper to install, would be better for us, together with a small immersion for DHW. Running costs may be higher and we can't guarantee that the electricity is all from renewables (but that goes for the ASHP too).  My other concern is about replacing the ASHP. By the time this happens we should be quite old, our income from pensions is fixed, we may have exhausted our savings and we have no prospect of inheritance. So we may not be able to afford to replace the pump.  I know electric heaters are dearer to run but compared to ASHP installation and replacement costs (assuming storage heaters last many more years and no maintenance costs either); is an ASHP worth it, both economically and ethically?  We have already insulated as much as we can with loft insulation and are about to install underfloor insulation and internal wall insulation on external walls.  Many thanks for any views.

Coastalwatch

Hi, and welcome there's a plethora of info on air to air heat source pumps in the link below should you wish for some bedtime reading. Some of it no doubt a cure for insomnia but the vast majority well sourced and relevant.

At £12k your quotation must surely have been for Air to water system where as Air to Air is far more cost effective and probably has a more efficient output, a ratio circa 4kW's out for each 1kW consumed. Also at a cost anywhere between £1k and £2k should easily see one installed. We live in a two bed bungalow and survive on two of the units entirely for heating. Depending upon room layout then it may be one unit can serve two, three or even four rooms.

I've no experience of storage radiators but presumably it's only 1kW of heat out for 1kW consumed! 

If you've a box of matchsticks handy then the thread below might well test it's contents.

https://forums.moneysavingexpert.com/discussion/4715287/discussion-ashp-air-air-with-solar-pv#latest

Hexane

Air source heat pump systems as a retrofit (essentially an air-to-water system that will heat your radiators and also your domestic hot water) have received much negative commentary on this forum. In this circumstance I think it would be even more negative, as you risk paying a heavy up front cost for a system that it sounds like you wouldn't use much at all.

But I would also be wary of electric storage heaters. Traditional storage heaters are a bunch of house bricks in a tin box with vents and some electrical heating coils (and sometimes a fan system). "Modern storage heaters" aren't hugely different except that the people who sell them need to persuade you that they are. I've spent a few years living in flats heated by them, and the most positive things I can say are that they rarely seem to go wrong and they do cost somewhat less to run than an ordinary electric heater. But that's about it. Controllability is poor, and they dry out the air in an unpleasant manner.

An air to air heat pump installing in the living room to supplement your log burner might well be the way to go. Because you've taken the commendable step of properly insulating your home, that may be all you need for heating. Several people on these forums use such systems to heat different parts of their homes by simply leaving the right doors open and letting the hot air push through. That would still leave you (or a subsequent purchaser) with the option, if needs change, of later installing one or more storage heaters, or ordinary electric heaters, in other rooms.

Alongside that you will need an immersion heater for your limited domestic hot water needs. Perhaps invest in a large well-insulated tank with both top and bottom immersion heaters. Then you could reduce the expense of heating it, and some of your other electric costs, by installing solar PV panels (if you don't already have them).

Solarchaser

Going by what you have said, you may find an under sink hot water heater most suitable for your needs, as its such occasional use.
Something like this is essentially an electric shower, but for your hot tap;-

https://www.screwfix.com/p/ariston-aures-electric-instant-water-heater-9-5kw/305FJ?tc=IT5&ds_kid=92700055281954502&ds_rl=1249404&gclid=CjwKCAiAzNj9BRBDEiwAPsL0d15b6yYKL2Zo0av0hmzhazWSOI1_rrjJk3rDnCw_N_s9JnCxxenR1BoChoUQAvD_BwE&gclsrc=aw.ds

If you have approached the EST and have been looking at rhi payments then it will be air to water heat pump they will be suggesting.
I couldn't make the numbers work for me, but the wife loves to open multiple windows in the house.... while having the heating on,  and heat pumps really need the house to be sealed is my understanding. 

However, from a green perspective,  you are likely to be on a good footing due to the amount of wind and hydro if you are north Scotland and if you are south Scotland as I am then it will be mostly wind and nukes.
With the future increases in wind farms its highly likely the overnight price of electricity will drop in the coming years, so perhaps storage heaters may be worth exploring,  though I bow to Hexanes experience here, having never actually used a storage heater myself.

The other option would be solar panels, with a solar immersion diverter, to your hot water tank which would also cut down on some of your electric bills as well.

EVandPV

Coastalwatch said:

Hi, and welcome there's a plethora of info on air to air heat source pumps in the link below should you wish for some bedtime reading. Some of it no doubt a cure for insomnia but the vast majority well sourced and relevant.

At £12k your quotation must surely have been for Air to water system where as Air to Air is far more cost effective and probably has a more efficient output, a ratio circa 4kW's out for each 1kW consumed. Also at a cost anywhere between £1k and £2k should easily see one installed. We live in a two bed bungalow and survive on two of the units entirely for heating. Depending upon room layout then it may be one unit can serve two, three or even four rooms.

I've no experience of storage radiators but presumably it's only 1kW of heat out for 1kW consumed! 

If you've a box of matchsticks handy then the thread below might well test it's contents.

https://forums.moneysavingexpert.com/discussion/4715287/discussion-ashp-air-air-with-solar-pv#latest

Regarding the air to air units, do you have an idea of how much power they consume over the course of a year ?

ASavvyBuyer

EVandPV said:

Coastalwatch said:

Hi, and welcome there's a plethora of info on air to air heat source pumps in the link below should you wish for some bedtime reading. Some of it no doubt a cure for insomnia but the vast majority well sourced and relevant.

At £12k your quotation must surely have been for Air to water system where as Air to Air is far more cost effective and probably has a more efficient output, a ratio circa 4kW's out for each 1kW consumed. Also at a cost anywhere between £1k and £2k should easily see one installed. We live in a two bed bungalow and survive on two of the units entirely for heating. Depending upon room layout then it may be one unit can serve two, three or even four rooms.

I've no experience of storage radiators but presumably it's only 1kW of heat out for 1kW consumed! 

If you've a box of matchsticks handy then the thread below might well test it's contents.

https://forums.moneysavingexpert.com/discussion/4715287/discussion-ashp-air-air-with-solar-pv#latest

Regarding the air to air units, do you have an idea of how much power they consume over the course of a year ?

The spec for the Fujitsu model we recently had installed states an average consumption of 658kWh/Year for heating in the UK.

The original Toshiba model we have in the lounge is about 850kWh/year according to the spec.

However, in Spring & Autumn, most of that power, if not all, is coming from out Solar PV system.

EVandPV

ASavvyBuyer said:

EVandPV said:

Coastalwatch said:

Hi, and welcome there's a plethora of info on air to air heat source pumps in the link below should you wish for some bedtime reading. Some of it no doubt a cure for insomnia but the vast majority well sourced and relevant.

At £12k your quotation must surely have been for Air to water system where as Air to Air is far more cost effective and probably has a more efficient output, a ratio circa 4kW's out for each 1kW consumed. Also at a cost anywhere between £1k and £2k should easily see one installed. We live in a two bed bungalow and survive on two of the units entirely for heating. Depending upon room layout then it may be one unit can serve two, three or even four rooms.

I've no experience of storage radiators but presumably it's only 1kW of heat out for 1kW consumed! 

If you've a box of matchsticks handy then the thread below might well test it's contents.

https://forums.moneysavingexpert.com/discussion/4715287/discussion-ashp-air-air-with-solar-pv#latest

Regarding the air to air units, do you have an idea of how much power they consume over the course of a year ?

The spec for the Fujitsu model we recently had installed states an average consumption of 658kWh/Year for heating in the UK.

The original Toshiba model we have in the lounge is about 850kWh/year according to the spec.

However, in Spring & Autumn, most of that power, if not all, is coming from out Solar PV system.

Thanks.
So are the units that provide heating/cooling for each room mounted up high or at floor level ?

ASavvyBuyer

EVandPV said:

ASavvyBuyer said:

EVandPV said:

Coastalwatch said:

Hi, and welcome there's a plethora of info on air to air heat source pumps in the link below should you wish for some bedtime reading. Some of it no doubt a cure for insomnia but the vast majority well sourced and relevant.

At £12k your quotation must surely have been for Air to water system where as Air to Air is far more cost effective and probably has a more efficient output, a ratio circa 4kW's out for each 1kW consumed. Also at a cost anywhere between £1k and £2k should easily see one installed. We live in a two bed bungalow and survive on two of the units entirely for heating. Depending upon room layout then it may be one unit can serve two, three or even four rooms.

I've no experience of storage radiators but presumably it's only 1kW of heat out for 1kW consumed! 

If you've a box of matchsticks handy then the thread below might well test it's contents.

https://forums.moneysavingexpert.com/discussion/4715287/discussion-ashp-air-air-with-solar-pv#latest

Regarding the air to air units, do you have an idea of how much power they consume over the course of a year ?

The spec for the Fujitsu model we recently had installed states an average consumption of 658kWh/Year for heating in the UK.

The original Toshiba model we have in the lounge is about 850kWh/year according to the spec.

However, in Spring & Autumn, most of that power, if not all, is coming from out Solar PV system.

Thanks.
So are the units that provide heating/cooling for each room mounted up high or at floor level ?

The inside units are mounted up high. When heating the airflow is aimed down automatically, when cooling straight out.

The new one in our kitchen is mounted above the window.

EVandPV

ASavvyBuyer said:

EVandPV said:

ASavvyBuyer said:

EVandPV said:

Coastalwatch said:

Hi, and welcome there's a plethora of info on air to air heat source pumps in the link below should you wish for some bedtime reading. Some of it no doubt a cure for insomnia but the vast majority well sourced and relevant.

At £12k your quotation must surely have been for Air to water system where as Air to Air is far more cost effective and probably has a more efficient output, a ratio circa 4kW's out for each 1kW consumed. Also at a cost anywhere between £1k and £2k should easily see one installed. We live in a two bed bungalow and survive on two of the units entirely for heating. Depending upon room layout then it may be one unit can serve two, three or even four rooms.

I've no experience of storage radiators but presumably it's only 1kW of heat out for 1kW consumed! 

If you've a box of matchsticks handy then the thread below might well test it's contents.

https://forums.moneysavingexpert.com/discussion/4715287/discussion-ashp-air-air-with-solar-pv#latest

Regarding the air to air units, do you have an idea of how much power they consume over the course of a year ?

The spec for the Fujitsu model we recently had installed states an average consumption of 658kWh/Year for heating in the UK.

The original Toshiba model we have in the lounge is about 850kWh/year according to the spec.

However, in Spring & Autumn, most of that power, if not all, is coming from out Solar PV system.

Thanks.
So are the units that provide heating/cooling for each room mounted up high or at floor level ?

The inside units are mounted up high. When heating the airflow is aimed down automatically, when cooling straight out.

The new one in our kitchen is mounted above the window.

Cheers.
I think that's possibly the way we'll go when the time comes to replace our gas boiler.

JKenH

EVandPV said:

Coastalwatch said:

Hi, and welcome there's a plethora of info on air to air heat source pumps in the link below should you wish for some bedtime reading. Some of it no doubt a cure for insomnia but the vast majority well sourced and relevant.

At £12k your quotation must surely have been for Air to water system where as Air to Air is far more cost effective and probably has a more efficient output, a ratio circa 4kW's out for each 1kW consumed. Also at a cost anywhere between £1k and £2k should easily see one installed. We live in a two bed bungalow and survive on two of the units entirely for heating. Depending upon room layout then it may be one unit can serve two, three or even four rooms.

I've no experience of storage radiators but presumably it's only 1kW of heat out for 1kW consumed! 

If you've a box of matchsticks handy then the thread below might well test it's contents.

https://forums.moneysavingexpert.com/discussion/4715287/discussion-ashp-air-air-with-solar-pv#latest

Regarding the air to air units, do you have an idea of how much power they consume over the course of a year ?

That  will depend on how much you run them and internal and external temperatures. Just recently I reported on the ASHP with Solar thread that last week that with 60 hours use over a week maintaining 23*C inside and mild outdoor temps mine used 230 watts per hour but in cold weather (around freezing) consumption has been as high as 500watts. That is for a nominal 3.5kW unit in a 38sq.m room with door open to the hall.

EVandPV

I'm guessing we'd maybe need to consider a bit more battery storage, a couple more Pylons ??
How do you guys heat your water when there's little to no PV ?