ASHP running cost

gazb_2

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

Netexporter

There are too many variables to draw any conclusions from what others are paying.

If you achieved an average COP of 3 for your heat pump, at SVT prices the heat pump will cost slightly more than gas. However, a TOU tariff, like Octopus Cosy, may make the heat pump cheaper, if the off-peak times fit well with your lifestyle. If you have solar and/or batteries then you may be able to tip the scales further in favour of an ASHP.

markin

The EPC rating and the annual primary energy from it along with the size will give a better comparison.

ArbitraryRandom

Netexporter said:

There are too many variables to draw any conclusions from what others are paying.

If you achieved an average COP of 3 for your heat pump, at SVT prices the heat pump will cost slightly more than gas. However, a TOU tariff, like Octopus Cosy, may make the heat pump cheaper, if the off-peak times fit well with your lifestyle. If you have solar and/or batteries then you may be able to tip the scales further in favour of an ASHP.

You mention lifestyle - With heat pumps, how similar to gas are they in use? I've heard that with the lower temps (even with larger rads) they need to be on longer to provide heat at the same times, but I don't know if it's longer or earlier? 

markin

The octopus designed heatpumps are advertised as high heat and more like a boiler and the cosy tarrif is matched to that.

MultiFuelBurner

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

How much in kWh are you using to heat your house currently. 

It doesn't matter a jot what a random property in the UK with unknown EPC is running their ASHP for it only matters how efficient your house is at retaining heat and your current usage in KWH for you to be comfortable.

Reed_Richards

ArbitraryRandom said:

You mention lifestyle - With heat pumps, how similar to gas are they in use? I've heard that with the lower temps (even with larger rads) they need to be on longer to provide heat at the same times, but I don't know if it's longer or earlier? 

Heat pumps are often used in conjunction with Underfloor Heating.  Underfloor Heating responds very slowly to changes in the feed water temperature so needs to be on for long periods, quite possibly 24/7.  But that applies whether your UFH is heated by water heated by gas or oil or a heat pump or heated by electricity.

If you have a heat pump and radiators then the speed with which you can increase the temperature depends on the size (i.e. surface area of the radiators) and whether you can boost the water temperature to provide faster heating when required.  Radiators specified for gas boilers are often loosely specified and may be oversized for the normal boiler operating temperature which will enable you to raise the temperature faster than with a heat pump where radiators are usually right-sized to exact specifications. 

Also many gas boilers use a feature called Load Compensation which boosts the water temperature when there is a big difference between the actual temperature and the temperature set on the room thermostat.  This enables you to raise the temperature faster.  Load Compensation is less common with heat pumps and always requires that you use the manufacturer's own room thermostat, not one supplied by a third party (which you can do with many gas boilers).

I have a heat pump, radiators and a third party thermostat made by Drayton Wiser.  In winter I switch on a feature on the Drayton Wiser called Comfort Mode which turns my heating on early in order to reach the right temperature at the right time.  The heating goes off at 22:30 and typically Comfort Mode switches it on again at 04:00 in order to reach my desired temperature by 07:00.    

Netexporter

ArbitraryRandom said:

Netexporter said:

There are too many variables to draw any conclusions from what others are paying.

If you achieved an average COP of 3 for your heat pump, at SVT prices the heat pump will cost slightly more than gas. However, a TOU tariff, like Octopus Cosy, may make the heat pump cheaper, if the off-peak times fit well with your lifestyle. If you have solar and/or batteries then you may be able to tip the scales further in favour of an ASHP.

You mention lifestyle - With heat pumps, how similar to gas are they in use? I've heard that with the lower temps (even with larger rads) they need to be on longer to provide heat at the same times, but I don't know if it's longer or earlier? 

"Low and slow" is the best way to run a condensing gas boiler, too. Many of out lifestyles have adapted to being able to come and whack the gas boiler on and start feeling the benefit in around 15 minutes. Assuming a reasonable level of competence in the design and installation of a heat-pump system, I believe a lot of the reported "problems" are people expecting it to act the same way as a gas/oil-fired system.

It is better for the building fabric not to be subjected widely fluctuating temperatures, too.

Alnat1

Find out how much gas you used over the last year in kWh, an ASHP is going to, very roughly, use around 1/3rd of that in electricity.

You'll save more if you address any issues with insulation but that applies with gas heating too.

If the gas is cut off after ASHP installation you'll be saving £100 on the standing charge but you might need to buy a new cooker.

Time of use tariffs might help a bit but as ASHPs work by being on low 24/7 to heat the house, much of the saving will be from heating hot water and running appliances at cheaper times

matelodave

As above, work out how much gas you used last year, divide it by three and multiply it by the cost of leccy and that will give you a very rough idea of how much it will cost you to run a heat pump. There are a lot of other variables but improving insulation will help reduce costs by retaining heat (whether you've got a heat pump or not).

Likewise, running any sort of heating system at a lower flow temperature will reduce the running costs but most people expect a quick warm up, especially if they only want heat for an hour or so in the mornings and  3-4 hours in the evening. The higher the flow temperature the more it will cost you to run and that is especially true for a heat pump

Try turning down your boiler to say 50 degrees and run it for longer - it may take longer to get your place up to temperature but you should save some money, especially if you've got a condensing boiler. 

Much like driving your car, a gentle 50mph cruise will use a lot less fuel than blatting along at 80. It'll take a bit longer to get there but will save you money and stress.

shinytop

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.