People Saying Heat Pumps are Rubbish - Are They?

Spies

7 of my 8 radiators were replaced, the total cost of my install was about £1200 (including £100 referral) 

Netexporter

Reed_Richards said:

Hoenir said:

Reed_Richards said:

I have had a heat pump for 4 years now; before that I had an oil boiler.  My heat pump keeps my house just as comfortably warm as before, but I had to replace nearly all my radiators with ones having a larger surface area as part of the installation.  Running costs have been a bit less than they were for my oil boiler but it's not made a huge difference because electricity costs a lot more per kWh than oil or gas.

What was the total cost of the installation can I ask? 

My bungalow, built in 1980, had the copper pipes that fed all the radiators buried just below the surface of the screed and unprotected.  Since this is a recipe for corrosion and eventual leaks in the long term, we took the opportunity to put new pipes in the loft to replace the existing ones.  But this made the installation need much more time and effort; it was almost like installing a complete new heating system.  So unless you want to do much the same thing there is no point in my telling you how much it cost.  It took two weeks with an average of about two people working per day.  

I had a completely new ASHP system fitted in my 1980s bungalow in two days by two blokes on the plumbing. There was a separate gang of sparkies to wire it up and install the solar PV for just over half of the second day.

I had already removed the old LPG microbore system myself, which probably saved them half a day.

Spoonie_Turtle

Ours took 2 or 3 days I think, can't quite remember.  Taking out storage heaters and immersion, and plumbing for the heating was all from scratch.  (9 rads, 3-bed 1940s semi.)

matelodave

Our took a week or so but that did include an overlay underfloor heating over the whole ground floor of a 140m2 bunglalow, two manifolds and completer replacement of all the plumbing from the stopcock to all the taps as well. That was 14 years ago.
The heatpump, tank and installation was around £7k and the underfloor installation was about the same (£14k in all). When we had it installed an oil installation would have been around 4k plus the cost of radiators or underfloor.
However as the place was being gutted we had the opportunity to install underfloor which does give a nicer feel than rads as it even all over. It also allow furniture to be place where you want it and avoid cover radiators with long curtains etc. We also don't have a big oil or lpg tank in our garden like most of our neighbours or the aggro of getting it filled.

As others have said a properly installed and commissioned installation and taking a bit of effort on understanding how it works and how to operate it correctly and they work and work well. However that said, its doubtful that they any cheaper to run than a gas or oil system at the moment, but that's because of the silly price of electricity compared to gas or oil.

To break even on running costs with gas you need a COP of at least 3.5 and possibly 4 or more for oil if you can get it for 55p/litre.

Tallmark

We’ve been very pleased with our Vaillant heat pump which was installed in early October. The house is heated to a constant 20 during the day, then setback to 18 overnight - very comfortable and quieter than the old gas boiler.  Bills are currently similar to what we paid to run our gas boiler on timed slots. Carbon savings are equivalent to 5 transatlantic flights a year. 

I can recommend Nesta’s visit-a-heat-pump scheme for a reality check on heat pumps and to check out local installers’ work. As others have mentioned, the quality of the system’s design and installation is critical to efficiency. We also got an additional £2k back from our mortgage provider, Barclays, under their Greener Homes scheme. I think Lloyds offer something similar. 

benson1980

Similar experience to Spies (and others) from the looks of things. Much more comfortable house, for similar energy costs. We've just had a Powerwall installed which takes advantage of the HP tariffs thus will significantly reduce- projected payback around 7 years.

I think some of the bad press comes from both poor installs for sure, but also a significant degree of lack of consumer knowledge about their energy costs. In relation to the latter, you'll have someone complaining about their 'huge' electricity bill post install during the winter months, but will have no idea what their respective gas and electricity usage and cost was before, and that it was in fact probably around the same for that particular month. They just didn't notice or monitor it in the same way, and paid a set direct debit oblivious to how much it spikes for 3-4 months of the year.

One might also consider that there is only one way gas prices are going, at some point potentially, to encourage more take up of renewables.

Reed_Richards

I rather surprised that nobody has posted here yet to say that heat pumps are rubbish.  I don't agree, but there are some easy ways to go wrong with a heat pump, such as expecting one to work as a direct replacements for a gas or oil boiler.  When I was looking to get a heat pump back in 2020 I was warned-off by a neighbour who said that the heat pump he had in a previous property had left him cold and with huge bills.  I never established what went wrong but it could easily be that his radiators were not big enough so the heat pump spent all it's time running at the maximum flow temperature whilst the radiators were still not managing to keep his house warm enough, because they were specified for a higher flow temperature.  

Exiled_Tyke

benson1980 said:

Similar experience to Spies (and others) from the looks of things. Much more comfortable house, for similar energy costs. We've just had a Powerwall installed which takes advantage of the HP tariffs thus will significantly reduce- projected payback around 7 years.

I think some of the bad press comes from both poor installs for sure, but also a significant degree of lack of consumer knowledge about their energy costs. In relation to the latter, you'll have someone complaining about their 'huge' electricity bill post install during the winter months, but will have no idea what their respective gas and electricity usage and cost was before, and that it was in fact probably around the same for that particular month. They just didn't notice or monitor it in the same way, and paid a set direct debit oblivious to how much it spikes for 3-4 months of the year.

One might also consider that there is only one way gas prices are going, at some point potentially, to encourage more take up of renewables.

I was almost caught out by this issue. Just had my mid-December electricity bill for £240 and was shocked. It was only when I checked last year's bill for the same period did I realise that is was substantially less than my previous combined gas and electricity. 

As COP worsens in colder weather I'm guessing the energy consumption 'spike' for those months could be more extreme than for gas heating?  Does anybody (particularly with a weather compensation (WD curve) set up have useful experience to share? 

Strummer22

Exiled_Tyke said:

As COP worsens in colder weather I'm guessing the energy consumption 'spike' for those months could be more extreme than for gas heating?  Does anybody (particularly with a weather compensation (WD curve) set up have useful experience to share? 

I have a GSHP which protects me somewhat from spikes in consumption during very cold weather as the source temperature doesn't vary as much. Even so, I notice that cold spells result in considerably higher consumption.

Approx figures for a "typical" winter day, perhaps with an outdoor low around 3°C and high around 8°C, the heating will be on for about 12 hours with a flow temp 38 - 42°C. This will use 15 - 20 kWh of electricity (it's a large and somewhat leaky old house). COP would be 4.5 - 5.0.

When much colder and/or windier - think hard frost, not getting above freezing all day, biting winds - the heating will be on for 16+hours with a higher flow temp up to 48°C. This could use up to 50 kWh with a COP as low as 3.0 - 3.5. For those with an ASHP those coldest days may see a COP as low as 2.0. I usually fire up the wood burner in these conditions so the heat pump doesn't have to work so hard.

Based on the above, in a winter month with no really harsh weather we can expect to use about 600 kWh of electricity on heating. However, if we have a week-long cold spell this would jump to 810 kWh. I think my worst month since install in March 2022 has been just below 1 MWh. 

Heat pump owners need to be able to take those spikes in context and consider that over a year the cost is comparable to gas/oil - not fixate on the fact that on particularly cold days taken in isolation, gas or oil would have been considerably cheaper.

Reed_Richards

My heat pump has its own electricity meter (which was a requirement of the grant scheme when it was fitted).  This is a chart of the electricity usage (in kWh).