Air Source Heat pump costs

[NextInLine]

How much is it costing you per day to run your ASHP?
I'm currently at about £12-£13 per day and I've only got it on 15degrees!
Do I need to amend the settings? Or is this right?

I really feel for you going through this as well,it's horrible. I completely share all of your concerns too,we bought into this naively that it was actually a real bonus to the house we were buying,I suspect by the time we come to sell people will be less naive when it comes to ashps. I wonder what to do when it inevitably breaks down too, it was Installed possibly 10 years ago - I certainly don't want to put another one in,but then what to do instead? There is no gas here,everyone's on oil,but is installing oil at this point risky ,are the coasts of that going to spiral in the coming years ?I don't know what to do at all really

Hi @Sienatulipa that definitely doesn't sound right. We're on about £7 a day this month, up to £10 yesterday but it was below freezing all day, we're in a 4-bed detached.

Hard to understand what the reason for your high electricity use is but things to ask the installer are:

What is the flow temperature (ie temperature of the radiators)?. It may be that if your house is getting cold, it is set up to try and heat as fast as it can, and so running inefficiently.

You need to have it set up so the flow temperature is always low, even if that means running the system for longer. If you allow the pump longer to put the same amount of heat into your house it will be cheaper.

The pump might be 'cycling' so ask your engineer about that. Cycling means rhe pump pushes out hot water faster than your house can cool it down and it is still warm when it gets back to the heat pump, so it turns itself off.

It can a be a problem if the pump is too big for the system. Do you know what size the pump is? For a normal sized well insulated house it should probably only be 5-6 kW. If you were sold a bigger one that might be causing problems.

Alternatively if the pump is too small (unlikely) it may be using a supplementary heating coil to try to warm your house up quickly. You need to ask this too!

The other thing to ask about is the hot water. It is much more efficient for the heat pump to heat the tank to 48 or so degrees than the usual 60 or 70, so the tank should have been sized to allow that. Ask the installer what your hot water setting is. If they have set it to 55 or 50 that will be costing extra money too. I assume you do not have an immersion heater connected? If so, check it isn't coming on.

Most installations then run a 'legionella cycle' to heat up the t ank periodically to kill any germs. No-one really knows how often this should be done, but if yours is happening wekly that is probably a waste. Monthly should be more than frequent enough.

Lastly your bills should drop significantly as the weather gets milder. So if it's 10 degrees outside not only does the house need less heat than when its 0, that heat should be about 25% cheaper, so your bills should very much be weighted into the coldest weeks if the year . An estimate of £5k is averaging £400 a month right across the year. Unless you are also running a hot tub you haven't told us about, I can't believe that youll be using that much in the summer especially with solar.

(Unless the engineer has done something really stupid and somehow got the hot watertank heating the solar panels and the sky...🤷)

PS I meant to say, radiator temperatures ought to stay below 45 ideally. We run ours mostly between 30 and about 40 (its 38 at the moment, 18 indoors -1 out) using weather compensation (ie the heat pump automatically turns the flow temp up and down based on the weather). Gas engineers who insta)l heat pumps sometimes set them to run at 55 all the time, using the same logic as a gas boiler. This is not a good way to do it, it might double your bills .

If you want more help dm me x

Oops spotted a typo I meant if the hot water tank is set to 55 or 60 it should probably be turned down. 50 would be fine.

I was speaking to an electric engineer from one of the big six yesterday and he agreed these can be very problematic and they are becoming the smart meter of now ie not popular with people generally because there are issues .

My friend has an ASHP and it's connected to their (very) old radiators. She reckons hers is great but her house is insulated & sealed to within and inch of it's life and she also has 2 log burners.

There is so much variability in housing and heat pumps are a finely tuned solution.

I agree that the heat leak has to be consistent with what the pump outputs. This is one of the problems, that the pumps aren't powerful enough to heat the house. House insulation varies over the UK hugely. But remember its not just about whether the pump has the actual power to maintain the temperature, but how much it costs to do so.

Then there is SCOP. A pump in mild southern England is going to perform much more efficiently than a pump in Scotland where the temperatures might be significantly lower in winter.

Then there is the cost of the tech, and the ability to get engineers to maintain it.

I think the pumps are ok if the house is designed for heat pumps from scratch. But retrofitting it to a place already with gas mains and a gas boiler seems madness to me.

I think for me a bigger question is whether it is a good replacement for oil and LPG if you don't have access to mains gas, and this is a much harder question to answer.

I feel sorry for people who have laid out the cash and are not getting what they need from the pumps, not only for them, but also for the reputation of pumps in general because I believe they are a good solution in certain circumstances.

For people using log burners as well, do you end up having the heat pump for hot water only? Log burners throw out a lot of heat, surely it gets very hot if you have heating on as well.

Your u/f heating only switches on when your room is below the room stat setting, if your wood burner heats the room to the stat setting your underfloor heating won't come on.

I love my ASHP, it works well and the cost is low. I live in a small and well insulated new build though, which probably helps immensely.

I'm so sorry to hear so many people having an awful and stressful time of it, I hope you figure it out, it's sometimes not easy being green :-(

We replaced out gas boiler with a heat pump about a year ago, because we wanted to support the industry and technology and cut our carbon footprint. Our overall energy usage is a lot lower, but because 1kWh of gas is so much cheaper than 1kWh of electric our costs are about the same (once you account for our tariff increasing). We replaced our gas hob with an induction so we could shut off the gas and stop paying the standing charge.

In terms of heat, well, the house is a poorly insulated, solid walled, bog standard 1930s place. It was cold and expensive to heat before, and it is equally cold and expensive to heat now! We have plans for insulation, that we haven't done yet, and that should make a big difference.

We use the heat pump like we used to use our boiler, so we mostly keep it off, and switch on for evening hours or when its particularly cold - I don't really understand the "background" heat thing - maybe it's something that makes sense if you have the insulation to retain it. We replaced the single radiators for doubles when it was installed, so although they don't ever get red hot, they overall give off a similar amount of heat. Because it's just me in the house right now, I'm sat at my computer with the heating off, and a blanket and a hot water bottle. But it's the same story for my colleagues over zoom with gas boilers. Me and another lady call ourselves the "dressing gown crew" because we are often on calls together wearing our dressing gowns over our clothes !

I agree with a previous poster that we should be investing lots more in insulation. People I know who live in well insulated new builds or flats often say they don't even need to turn their heating on until well into December.

I think the hydrogen boiler thing, in the long-run won't work, just because of the maths of the efficiencies really: heat pumps give you more energy than you put in, but hydrogen gives you significantly less energy than you put in. h2sciencecoalition.com/blog/hydrogen-for-heating-a-comparison-with-heat-pumps-part-1/.

To me that is an incredibly naive article because as far as I saw it makes no mention of one of the key issues with hydrogen, which is that you can use it as a power storage medium. The electricity supply from wind is just too erratic. When the wind doesn't blow and its cold (correlated) and everyone turns on their heat pumps what's going to happen ?

It's also an incremental addition to the current system. Most boilers will burn up to 20% hydrogen already, so hydrogen can be added in to the mix over time as it becomes available.

I am not sure we will ever get 100% hydrogen, but I think 20% is a real possibility and a useful contribution to net zero that can be implemented at little cost.

The heat pump provides background heat and easily enough to sleep in.

But it might not be enough to sit in comfortably, hence the log burner in the sitting room

@MintJulia ah ok, yes that makes sense.

The heat pump provides the background heat for the whole bungalow, the log burner is just for the living room although I’m putting one in the kitchen as well.

@GasPanic if you have a 20% hydrogen blend, then you are still using 80% natural gas with the associated carbon emissions and will never reach net zero.

Hydrogen for home heating is a myth made up by the oil and gas companies (the vast majority of hydrogen currently comes from natural gas, emitting a load of carbon dioxide in the process), the gas networks, and boiler manufacturers. It’s never going to happen - there isn’t the technology to make anywhere near the amount needed at scale, and it’s incredibly expensive and inefficient.

sorry to weigh in on a thread about heat pumps but this is a real bugbear of mine! Heat pumps and heat networks are the only way we can reach net zero for heating, but i agree there needs to be a significant improvement in the quality of the installation and the product, as demonstrated by the nightmare stories on this thread.

@GasPanic the article wasn't about hydrogen for energy storage, which is a different situation to using it inside boilers for heating. If you used it for energy storage, you'd likely store it close to where it was generated (hydrogen is hard to store and transport), and then when you want to use it you wouldn't burn it. You would run it through a fuel cell to produce electricity. Then you would put that electricity on the grid to make up for short-falls in renewable energy output.

Hydrogen definitely does have lots of uses. For example, you could use it to make steel, or you can turn it into ammonia and use it to make fertiliser (which is pretty amazing, imagine if a country like India, that spends lots of money importing fertiliser, managed to create their own using solar energy). But like @BigHeartyTruffle I have my suspicions about fossil fuel companies trying to find a new market for their products by generating hydrogen from natural gas, and then effectively selling gas with a lovely green hydrogen halo. (Also sorry for the thread derailment, I really shouldn't have mentioned the ASHP vs. hydrogen boiler thing!)

My understanding is that ASHP’s work best with underfloor heating not radiators.

"the article wasn't about hydrogen for energy storage"

What a co-incidence, because that happens to be one of hydrogens greatest strengths.

"You would run it through a fuel cell to produce electricity. Then you would put that electricity on the grid to make up for short-falls in renewable energy output."

I'd be interested in knowing how that is going to provide the UKs domestic heating requirements without a massive upgrade to the electricity grid infrastructure, since it would probably require the grid to have 2-3 the transmission capacity that it currently has, and cope with peak demands in excess of 150 GW (current electricity generation is about 30-40GW). This of course is without any other grid upgrades that might be required - for example powering electric cars.

The gas grid already has the capability to transmit the energy with little or no added cost. We can transmit 20% hydrogen over it and achieve the equivalent of taking 1.5-2 million cars off the road without imposing significant costs on homeowners for boiler upgrades. The cost is in the electrolysis plants.

"have my suspicions about fossil fuel companies trying to find a new market for their products by generating hydrogen from natural gas, and then effectively selling gas with a lovely green hydrogen halo."

We already have green, blue, turquoise and grey hydrogen. I don't think we need another made up term like "green hydrogen halo".

Hydrogen in the domestic gas grid is going to happen. There is no other cost effective way we can mitigate the variability in wind power and also deliver the energy to where it is required. Whether we move up to 100% on the grid, I think that's a different question. If we do it won't be for decades.

The initial trials on this are complete (Keele, 2021). More trials are underway and the next stage is to test at town scale.

hydeploy.co.uk/about/news/first-uk-trial-of-hydrogen-blended-gas-hailed-a-success/

Government approval for the grid will follow shortly.

assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1011283/UK-Hydrogen-Strategy_web.pdf

They do work OK with radiators. It's just that you need a larger surface area to heat the house as the system runs at a lower temperature, so if you are using radiators they have to be bigger than what you would use for gas/have a much larger surface area.

It's easier (and more asthetically appealing) to get that large surface area by putting the radiators under the floor (underfloor heating) than it is covering the walls with radiators !