UPDATED: Air Source Heat Pumps/Air Con - Full Info & Guide, is it cheaper to run than mains gas?

matelodave

AS said by others, it wont be as cheap to run as a mains gas heating system and you do need to make significant changes to the way you use it - it does not give on-demand heating like a gas boiler does. If its installed and configured correctly then IMO it costs about the same to run as oil, less than LPG and about twice as much as mains gas. However, if it's not installed configured or operated correctly then it can be very expensive to run. They are more suited to those who are at home all day who keep the house warm for long periods of time rather than short heat up in the mornings and evenings.

It really is difficult to see into the future to understand how energy prices will change, especially if there's a real push to reduce the use of fossil fuels.

Being cynical, I'd guess that Eon are doing this as part of their Eco obligations and they may even be able to claim the Renewable Heat Incentive payments so you'd need to establish the ownership of the installation to ensure that you do actually own it out right and not necessarily at the end of a long period (say the 7 years of the RHI payments) as that could cause problems if yo decide to sell the place.

Regarding enhancing or detracting the value of you home, I'd suggest that this is down to the buyer's attitude when the time comes.

Having it done for free sounds very attractive and I'd be jumping at the chance, but that's only because we don't have mains gas. I do have an ASHP, and I do get the RHI (£5k over 7 years in my case) but I'd have gone with mains gas if it was available (and TBH I might even change to a conventional system if mains gas became available).

jonno147

Thanks for all the comments
Now I have a bit more knowledge on the system I would tend to agree Mikeeuropa - for me receiving an email out of the blue, which looked to be promising free stuff and possibly cheaper bills, seemed too good to miss out on - since I've read this thread and looked further into the costs of actually running ASHP, it maybe that it's not the right choice for me. I've really appreciated the responses to my question. So thanks. Plus it's not a bad thing to have a rant now and again. Stay safe.

danrv

richardc1983 said:

Running costs for gas is cheaper than an ASHP purely based on price per kwh of gas vs electric. An ASHP doesn't add value as such as I found out myself when I was considering selling my home. For some the benefit of cooling may be seen as a bonus but many are not interested. On the other hand a "new heating system" with warranty will add value. 

Mmm... for my place with it’s 1970’s warm electric warm air system, it looks like only oil 
central heating is going to add value. Possibly also an ASHP rads system if sized correctly.
In the meantime, all I can do is smarten up the interior and keep using my £100 set of convectors (have turned off storage heater). 
Any expensive install can be done after redecorating. A good compromise might be air to air heat pump - a good bit cheaper than with radiators. 
At least it would be ‘a system’ and may even improve 
the EPC rating.

richardc1983

danrv said:

richardc1983 said:

Running costs for gas is cheaper than an ASHP purely based on price per kwh of gas vs electric. An ASHP doesn't add value as such as I found out myself when I was considering selling my home. For some the benefit of cooling may be seen as a bonus but many are not interested. On the other hand a "new heating system" with warranty will add value. 

Mmm... for my place with it’s 1970’s warm electric warm air system, it looks like only oil 
central heating is going to add value. Possibly also an ASHP rads system if sized correctly.
In the meantime, all I can do is smarten up the interior and keep using my £100 set of convectors (have turned off storage heater). 
Any expensive install can be done after redecorating. A good compromise might be air to air heat pump - a good bit cheaper than with radiators. 
At least it would be ‘a system’ and may even improve 
the EPC rating.

If mains gas is not an option then Oil is your next best option (albeit not as green and many would not have the space for the oil tank etc). ASHP or GSHP would be next followed by standard electric heaters being last.

Cooling is also available on Air to water heat pumps provided you use fan coils as the heat emitters. As in the summer the unit will produce chilled water vs hot water in the winter. 

Mikeeuropa

richardc1983 said:

If mains gas is not an option then ASHP is the next best option and cheaper to run than oil or normal electric heaters.

I'm not sure where you're getting your figures from but the figures on the link in my previous response don't agree with that statement. In September, ASHPs were calculated as costing 7.19p per kWh whereas oil was costing 3.33p per kWh. Admittedly that was based on an oil price of 29.41p/litre but doing the maths on a more recent price of 39.07p/litre it gives a price of 4.43p per kWh. Oil would have to go up to 63.42p/litre to match the 7.19p per kWh running costs of an ASHP (pre pandemic, oil hovered mostly a little below 50p/litre for most of 2019 - figures from Boilerjuice).

richardc1983 said:

Cooling is also available on Air to water heat pumps provided you use fan coils as the heat emitters. As in the summer the unit will produce chilled water vs hot water in the winter. 

I believe cooling is only available on some ASHPs, not all of them. I did wonder about fan convectors but if used for cooling what happens to the inevitable condensation? Do they all have to be mounted on an external wall to enable a condensate drain to be put through the wall?

richardc1983

Mikeeuropa said:

richardc1983 said:

If mains gas is not an option then ASHP is the next best option and cheaper to run than oil or normal electric heaters.

I'm not sure where you're getting your figures from but the figures on the link in my previous response don't agree with that statement. In September, ASHPs were calculated as costing 7.19p per kWh whereas oil was costing 3.33p per kWh. Admittedly that was based on an oil price of 29.41p/litre but doing the maths on a more recent price of 39.07p/litre it gives a price of 4.43p per kWh. Oil would have to go up to 63.42p/litre to match the 7.19p per kWh running costs of an ASHP (pre pandemic, oil hovered mostly a little below 50p/litre for most of 2019 - figures from Boilerjuice).

richardc1983 said:

Cooling is also available on Air to water heat pumps provided you use fan coils as the heat emitters. As in the summer the unit will produce chilled water vs hot water in the winter. 

I believe cooling is only available on some ASHPs, not all of them. I did wonder about fan convectors but if used for cooling what happens to the inevitable condensation? Do they all have to be mounted on an external wall to enable a condensate drain to be put through the wall?

Oil Prices have dropped but then would you want a big oil tank outside to store your oil? Not everyone has space and oil prices may shoot up. Personally if it was a choice between heat pump or oil I would have to go heat pump as I have no outside space for an oil tank. 

Yes only some systems will allow cooling, LG's version does. The condensation can either be drained through an outside wall via gravity or you can use a condensate pump for units that cannot be mounted on an external wall.

Mikeeuropa

richardc1983 said:

Mikeeuropa said:

richardc1983 said:

If mains gas is not an option then ASHP is the next best option and cheaper to run than oil or normal electric heaters.

I'm not sure where you're getting your figures from but the figures on the link in my previous response don't agree with that statement. In September, ASHPs were calculated as costing 7.19p per kWh whereas oil was costing 3.33p per kWh. Admittedly that was based on an oil price of 29.41p/litre but doing the maths on a more recent price of 39.07p/litre it gives a price of 4.43p per kWh. Oil would have to go up to 63.42p/litre to match the 7.19p per kWh running costs of an ASHP (pre pandemic, oil hovered mostly a little below 50p/litre for most of 2019 - figures from Boilerjuice).

richardc1983 said:

Cooling is also available on Air to water heat pumps provided you use fan coils as the heat emitters. As in the summer the unit will produce chilled water vs hot water in the winter. 

I believe cooling is only available on some ASHPs, not all of them. I did wonder about fan convectors but if used for cooling what happens to the inevitable condensation? Do they all have to be mounted on an external wall to enable a condensate drain to be put through the wall?

Oil Prices have dropped but then would you want a big oil tank outside to store your oil? Not everyone has space and oil prices may shoot up. Personally if it was a choice between heat pump or oil I would have to go heat pump as I have no outside space for an oil tank. 

Yes only some systems will allow cooling, LG's version does. The condensation can either be drained through an outside wall via gravity or you can use a condensate pump for units that cannot be mounted on an external wall.

You're absolutely free to conclude that you would rather have an ASHP, I was simply contesting your statement to another user on here that ASHPs were cheaper to run than oil boilers - they are not.

And yes I absolutely agree about oil storage tank considerations and the potential volatility in price, although looking at the graph of prices over the last 4 years I'd guess it averaged at mid40s pence/litre over those 4 years (45p/litre would equal 5p per kWh) so still cheaper than ASHP throughout that 4 year period. There are many other considerations such as the heating profile of the user - are they out at work all day and therefore fall into the "switch it on in the morning, off during the day, back on for the evening and off overnight" group for example. In which case an ASHP system would most likely output more kWhs over the year than a gas, or oil, or lpg boiler as it works most efficiently when on most of the time and therefore total year cost would be even more.

By the way, I would love it if they were a cheaper option as I try to be green where I can, I am not an anti-ASHP person. My aging oil boiler will no doubt fail some day and I'd love to replace it with something more green but I can't justify or afford the extra installation and running costs of an ASHP.

richardc1983

Mikeeuropa said:

richardc1983 said:

Mikeeuropa said:

richardc1983 said:

If mains gas is not an option then ASHP is the next best option and cheaper to run than oil or normal electric heaters.

I'm not sure where you're getting your figures from but the figures on the link in my previous response don't agree with that statement. In September, ASHPs were calculated as costing 7.19p per kWh whereas oil was costing 3.33p per kWh. Admittedly that was based on an oil price of 29.41p/litre but doing the maths on a more recent price of 39.07p/litre it gives a price of 4.43p per kWh. Oil would have to go up to 63.42p/litre to match the 7.19p per kWh running costs of an ASHP (pre pandemic, oil hovered mostly a little below 50p/litre for most of 2019 - figures from Boilerjuice).

richardc1983 said:

Cooling is also available on Air to water heat pumps provided you use fan coils as the heat emitters. As in the summer the unit will produce chilled water vs hot water in the winter. 

I believe cooling is only available on some ASHPs, not all of them. I did wonder about fan convectors but if used for cooling what happens to the inevitable condensation? Do they all have to be mounted on an external wall to enable a condensate drain to be put through the wall?

Oil Prices have dropped but then would you want a big oil tank outside to store your oil? Not everyone has space and oil prices may shoot up. Personally if it was a choice between heat pump or oil I would have to go heat pump as I have no outside space for an oil tank. 

Yes only some systems will allow cooling, LG's version does. The condensation can either be drained through an outside wall via gravity or you can use a condensate pump for units that cannot be mounted on an external wall.

You're absolutely free to conclude that you would rather have an ASHP, I was simply contesting your statement to another user on here that ASHPs were cheaper to run than oil boilers - they are not.

And yes I absolutely agree about oil storage tank considerations and the potential volatility in price, although looking at the graph of prices over the last 4 years I'd guess it averaged at mid40s pence/litre over those 4 years (45p/litre would equal 5p per kWh) so still cheaper than ASHP throughout that 4 year period. There are many other considerations such as the heating profile of the user - are they out at work all day and therefore fall into the "switch it on in the morning, off during the day, back on for the evening and off overnight" group for example. In which case an ASHP system would most likely output more kWhs over the year than a gas, or oil, or lpg boiler as it works most efficiently when on most of the time and therefore total year cost would be even more.

By the way, I would love it if they were a cheaper option as I try to be green where I can, I am not an anti-ASHP person. My aging oil boiler will no doubt fail some day and I'd love to replace it with something more green but I can't justify or afford the extra installation and running costs of an ASHP.

Original post updated...
If you have oil already then go with an oil replacement then if you already have the space for a tank etc. 

inmypocketnottheirs

Hmmmm, interesting stuff. 

Just going through the purchase of a new build property that meets all of our requirements.  The only thing that I’m unsure of is the already installed underfloor heating system with ASHP. It’s a wet system both down and upstairs with thermostats in each room. There’s a massive pressurised cylinder for hot water supply. 

Anyone with real world experience of such a system as I’ve only knowledge of oil or gas? 

matelodave

OK if you've got one learn how it operates and use it properly. Get yourself onto a decent tariff, IMO a cheap single rate one is better than an E7 tariff as it doesn't really work like a storage heater even with underfloor heating. You'll find that it's heating response times are very slow so don't expect it to heat up and cool down like a radiator system with a boiler. If it's running at it most efficient then it could take several hours to respond (our will take around 36 hours to reheat the house if we let it get stone cold)

Most problems with ASHP are either because they've been poorly specified or commissioned but also because people don't understand how they work and try to operate them like a normal boiler. Having the hot water or heating flow temperatures set too high will cost you dearly