ASHP running cost

MultiFuelBurner

shinytop said:

gazb_2 said:

I’m still torn on which way to to on our home, Gas or ASHP? 

How much are you spending on electricity running your ASHP? What’s the m2 of your property?

thanks

Since nobody else has answered the question, I will.  About 6500 kWh per year for heating and HW.  170m2 1990 bungalow.

You failed you haven't said gas or ASHP 🤣🤣🤣

matelodave

OK, my 13 year old 11kw Daikin heatpump uses around 4500-5000kwh a year for heating and hot water in a 1986 145m2 bungalow. We have cavity wall insulation (installed when it was built), 1999 vintage upvc double glazing, 300mm loft insulation and polypipe overlay underfloor heating.

We are at home all day and the heating is usually idling away 24/7 from November to March when we use around 70% of our annual energy

Total electricity consumption is around 7000-7500kwh a year - (it has been as low as 6500 and as high as 8500, depending on the weather)

Cost is a variable as the tariff price - a couple of years ago we were paying less than 10p/kwh when gas was around 2.5-3p and now we are paying around 28p/kwh whereas gas costs less than 7p, so leccy is still four times the cost of gas.

For a simple calculation 12,000kwh of gas  at 7p/kwh = £840, using a COP of 3 for a heatpump = 4000kwh at 28p = £1120, ie around £280 more. Put your own figure into the sums. You'd need to have your heatpump optimise and used properly to get a COP much better than 3 to 3.5. Although that said, those who are prepared to put the time and effort into understanding their systems and tweaking them could possibly achivee a COP of around 4.

I'm waiting with keen anticipation to hear how some of this years new heatpump owners get on over winter as I suspect newer heatpumps and keen owners can get a lot more out of them than those who expect to run them like a gas boiler.

Scot_39

Beware not all heat pumps were created equally.

So check specs carefully.

And some can be more optimised for low flow temperatures than you may be used to with gas central heating - especially if your used to the "fast warm up - hare vs tortoise approach".

And many are less optimised for cold northern temperatures - than you might think from those claiming COPS of 3-5s (my uncle in NE Scotland went GSHP - 3 years ago in end - as the ASHP COP ratings quoted for winter were poor).

There were also at least two different generic sorts of comprossor in use at one stage - there were some threads here on it in the past - cannot remember the exact details - but seemingly one needed a heater on the comprosser - when not itself running frequently for heating or hot water - which used to burn kWh of energy - in summer especially.  Some threads reported models as having "vampire loads" in kWh daily.  But that seems to have died down a bit here.

Increased Electrical Power Demand

In general you want to ask each supplier when they survey / quote - to check or how/what you need to check house in terms of wiring (incoming) against any new ASHP maximum input current demand.

Many homes will cope as is - but some have not.

Smallest ASHP may only need iirc 16A feed protection - but with size that will increase - some other sites suggest 30A circuits more normal - for isolation / protection and wiring used - and that's over and above all other household demands.

Many houses may only have 60A fuses and wiring - other homes 80A, 100A.

A minority have even lower ratings - according to UK power networks site - some fuses are as low as 30A.

Some homes also have shared electrical feed tap points with neighbour(s?) - meaning between homes - they cannot safely pull more combined load etc from the street wiring.

So some have found needed a fuse upgrade or even splitting off of a shared electric feed with neighbour(s) for safe operation.

And those in larger properties - have even found they need to go 3 phase - to overcome the 100A (about 23kW power) limitation (but the posts I remember here that was feeding 2 ASHP not just one).

Gerry1

If you go for a heat pump and then an EV, your electricity consumption and peak demand may triple.

You may have fun when your heatpump, oven, washing machine, tumble dryer, kettle etc are all calling for energy, especially if your workplace is not your home: your smart meter and/or your smart charger may hit you with Surge Pricing or just say NO.  You'll look back to the good old days when you just switched things on (and when car insurance was affordable).