Gas or Ashp

matelodave

I've got a heatpump which I've had for 13 years and ,although I'm more than happy with it ,I'd jump to gas if it became available where I live as It would be cheaper to run/ Even though we are reasonably well insulated and have underfoor heating.

Possibly a more modern unit would be a bit more economical but, until they start balancing out the cost of gas and leccy and not loading leccy with all the Eco stuff, a heat pump is still more expensive to install and run.

However all that said, make sure that whatever you install in the way of radiators, hot water tank or underfloor heating is sized for low flow temperatures (ideally no more than 40 degrees) so that it's heatpump ready in the future

Spoonie_Turtle

Alnat1 said:

Have a read about how well Finland is doing with heat pumps, a country that is much colder than the UK. 

Don't they have much better insulated houses though, built for the cold?

*I started typing this hours ago and got distracted, apologies if the conversation has moved on in the meantime!*


Efficiency wise I would say we were fairly typical ignorant ASHP users - social housing, EPC D (although in fairness the Housing Association do keep on top of insulation requirements, they're much better than a lot of private landlords seem to be), with an ASHP foisted on us and zero education of how to use it.  With the stat at 18℃, heating and hot water always allowed to kick in 24/7, the past couple of years before I learned about how it worked and how to tweak settings, the overall efficiency was 260% - that includes the summer vampire power for 'heating' which was 35-50kWh input for 0 output (I have no idea why, and most models don't seem to do that to be fair).

Since tweaking settings, last November was 370%, December 300%, January 320% and Feb 345%.  The heating has actually been more efficient than the hot water in the colder months, probably because we do still have a weekly legionella cycle which uses the immersion for the top few ℃, and the water into the system was much colder than in warmer months.

We certainly haven't tweaked our settings to maximum efficiency, and I'll only find out at the end of the year if they've made a real difference overall.  (The proper efficient way to run is low and slow 24/7 with weather compensation and whathaveyou and that's more work than we're prepared to do.)  The tweaks we made were not a lot of work, and didn't need much knowledge - they do however need more knowledge than we were ever given or than is in the manual!  But anyway, just thought I'd contribute our efficiency stats in light of the 'how much does it cost to run in cold weather?' question.

Mstty

@Spoonie_Turtle I think at the current rates you only have to be about 285% efficient to be cheaper than gas.

Most boilers over a 10 year lifetime will struggle to be 85% efficient, some don't even start that when when setup.

At 34p and 10.4p If we take into account efficiencies 

Gas price 10.4p 85%efficient = 11.96p kWh out

Elec price 34p 100% = 34p kWh out

If I was the OP and doing a renovation the decision would come.down to how good the insulation renovation is planned, whether underfloor heating is in the budget and if they were at home a lot.

chris1973

We have the greenest Electricity in history. Unfortunately we also have the highest Electricity prices in History too.

A friend of mine recently paid 69p per litre for a bulk delivery of heating oil, that is around 6.9p per kwh, which even with the efficiency losses from an average boiler is still far cheaper than mains Gas at just over 10p. I never thought I would see the day, where oil heating was significantly cheaper to run than Gas!.

That just shows how unpredictable the times we currently live in are, and I certainly wouldn't want to be taking guesses on how things are going to pan out in the future, especially if that prediction was followed by some kind of financial investment.

Germany are currently attempting to backtrack on their banning of the sale of ICE Cars by 2035, I suspect the trend will eventually spread to everywhere, when people finally wake up to the fact that Net Zero will be about as achievable as China's zero covid policy. When the penny finally drops I suspect there will be all sorts of backtracking including to looking at postponing the ban on the fitting of Gas boilers too. But like I say, unpredictable.

Not sure if its possible to fit a small gas boiler in conjunction with a ASHP, personally that would be one option I would be looking at.

gazb_2

We’re near York.

The house will have 75mm insulation on all external walls in line with current building regs. My wife is at home all day with out 2 young children. We’ll be having UFH either way and oversized rads upstairs.

it seems to be a very mixed bag

70sbudgie

I would look at the reasons why people regret installing ASHPs. Do any of those reasons apply to you? Are you prepared to put in the effort to avoid reasons that can be avoided? The problem with new technologies is that they require us to amend the way we do things. Some people are not prepared to do that and so will never be happy with the new technology. Are you someone who is prepared to make changes to your habits to make the most of the new technology?

My experience of this is from having an electric car. Instead of having to make time to stop at service stations to refuel, I plug in and program my car to charge at night. If I tried to use my car in the way I did its diesel predecessor, I would forever be getting in difficulty. But having made a change to my habits, I am now in a situation which is better for me in many ways.

BUFF

chris1973 said:

Not sure if its possible to fit a small gas boiler in conjunction with a ASHP, personally that would be one option I would be looking at.

It is but afaik hybrid heat pump installations don't qualify for grants.

markin

The problem is current regs are rather poor, new builds can be Epc D.

A/C units, air to air heatpumps are far easier and cheaper to install still get 300% efficiency, and can cool in summer.

Mstty

19 months into our ASHP life.

It did take us a year to get up to speed with the concept of low and slow. Many a time sat Infront of what I term the plant room cupboard and the controller to our heat pump.

For the first 6 months I was an inpatient tinkerer. Looking at the upcoming weather and selecting what I though was the lowest temperature we could sustain a good level of heat. Mixed results as weather reports are what they are and it took too much time so ended up setting it a bit higher than needed. Found out about weather compensation after 6 months and went with the default curve. 

The second year I started tinkering with the weather compensation curve and we now have a curve that is "nearly" there. 

Over October 2022-end of Feb 2023 we have saved over 727kwh compared to the same period a year earlier.

We are on schedule for a total usage (all heat hot water, all electricity) in our modern well insulated 4/5 detached house for approx 6150kwh this year. (Let's call that £2300 including SC on the EPG rates which we are not on but it helps others calculate)

As for a comparison a previous 3 bed link detached house on mains gas 2 years old with as high EPC B rating we used 2400kwh electricity and 13150kwh gas. For our region on EPG rates including SC that comes out at roughly £2450. Both houses we worked from home full time so same heating scenarios and temperatures required.

We can only compare our newish built house with high insulation levels and planned for purpose ASHP, not retrofit.

However it may be interesting for people considering a new build house with ASHP.

For us this much bigger house is cheaper to heat than the mains gas supplied previous smaller house.

But it has been some work to get the system running efficiently, no change in habits really now it is all setup but for those that are not in their house much they may bulk at heating a house when not at home to have a comfortable temperature when they are. To make an ASHP as reactive as a gas boiler for say an hour in the morning and a few hours at night you need to turn it up full whack and that is where it will costs 

gazb_2

Thanks mstty 

Our house is a detached bungalow, downstairs will be approx 1800sq2 and upstairs will be 1200sq2. 

Currently our 9” solid walled, un insulated bungalow is on a gas combi sat at 20oC 24/7 and is costing £480 per month! This is only short term until we start the work