Heat pump to replace boiler

[NCTDN]

We need to replace our boiler as it's 25 years old and totally inefficient.
I know there's old threads about heat pumps but has anyone got one recently?

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Updated by MNHQ
Landed on this page in search of heat pump advice? Find our guide to installing a heat pump in your UK home here. HTH!

No. I would be careful of getting one. They can work well sometimes but other times not. And they are expensive. Much more so than a boiler replacement.

Why do you want to replace a working boiler ? It will take a long time to recover the cost of the install in efficiency savings, unless you use an absolutely huge amount of gas.

The efficiency saving in going from an old to a new boiler is a nice bonus that can help offset some of the cost, but doesn't really justify a new installation on its own. Best reason to replace a boiler is because it is coming to the end of its service life - you can't get parts anymore or it is requiring expensive parts replacement, or breaking down all the time. If your boiler is a quality brand it could work for a long time yet.

Take a look and see if you're eligible through the ECO4 scheme - it often funds heat pumps and other energy efficiency measures. Your council will have a Statement of Intent.

Our boiler is leaking so needs fixing which seems pointless.
We are eligible for a grant.

I would see if it can be repaired. New boilers are often rubbish and have more plastic parts inside. Our fancy Vaillaint one lasted 8 years. Just replaced it .
All the plumbers we asked said it's about how long they often last now

Personally I'd get a Worcester Bosch combi and a service plan with Corgi. British Gas plans are definitely more expensive.

Heat pumps are problematic, be wary and do a lot more homework if you go for one.

Have had an air source heat pump for 10 months now. Have had no problems with it. It is quite noisy outside- not a problem for us but might be for some.
I don't like having a hot water tank rather than the constant hot water from a combi boiler. There are 5 of us and the tank would only do two normal length showers or maybe three very quick showers (try telling the teens to be quick.....
Even with solar panels it has not saved us money on our heating bills - we previously had an oil fired boiler and the cost is comparable.

If you don't mind me asking what was your installation cost ?

@GasPanic
It was free (in Wales) if your house meets the criteria (a low energy rating)

Ah right - ok.

Great deal and it sounds like you (almost) got everything you need, which I guess is a result !

I’ve been very happy with my heat pump. Over the summer it’s used 0.4kWhs every other day to heat all our hot water (efficiency 470-540%) As others have suggested I would recommend doing some background research and make up your own mind but bear in mind there is a lot of misinformation around. Octopus Energy today released their own heat pump with the 6kW version rolling out from Dec. They also currently fit other brands - either way they might be worth investigating. (FYI different colours will be available) https://www.msn.com/en-gb/money/other/octopus-unveils-product-to-end-the-world-of-ugly-heat-pumps/ar-AA1gIzUu

Get a proper heat loss survey done to see what you'd need doing if you got a heat pump. They work best running constantly (or nearly constantly) but at a lower heat so may not work well with existing radiators. You also need good insulation etc (although that applies whatever heating you've got!)

We have an ASHP which we're very happy with - but we replaced an ancient boiler with it in a house we'd just bought and also installed under floor heating at the same time. It works really well for our lifestyle where there's someone at home most of the time. Our house is big (6 beds) and sprawling (extensions in various directions) and about 90 years old and it works well for us but might be less good in a much older property.

The hot water cylinder with it is great and much better than our combi boiler in a previous house - always plenty of hot water and we only need to heat it every other day. Pressure is much better and we can run appliances at the same time as the shower without any problems.

I would fix the existing boiler in the short term.

You really need to do a lot of research before you get into heat pumps and you need to go into it with eyes wide open. It's not (or very rarely) just a case of replacing a boiler with the heat pump as a single component, you're essentially replacing your entire central heating system with something different and it all needs to be designed to work well as a whole. You may need to replace all your radiators, upgrade insulation etc.

Sorry to hijack this thread, but we are considering a heat pump system and wondered about what you thought. We have a provisional quote from our energy supplier for £2650 (plus the £7500 government grant). This includes replacement radiators if needed and hot water tank. We have £1000 credit on our utilities we could get back having overpaid, to contribute to the cost.

We're trying to get a bit more information before having them come round to do a survey.

Our house is 12 years old, 3 storey mid terrace. It is fairly well insulated and we mainly live on the 1st floor, which is the warmest and where our bedroom and living room are. Kitchen/diner and garage are on ground floor and that can be a bit chilly in the winter, but warms up when we cook. Teens rooms and home office where DH WFH are on 2nd floor. DH doesn't feel the cold like I do. One teen is at uni now and the other out at 6th form for 10 hours on weekdays including commute and stays at his dad's 3 nights a week.

Last winter we managed with heating on just for an hour in the morning and an hour in the evening. We were fine, although I wore lots of layers of clothes. The others didn't need to.

Boiler is now 12 years old, we've been told we should get up to 15 years out of it. It's part of a pressurised system which needed an expensive repair on the pressurised parts several years ago. This might happen again, last time it cost about £500. It also costs £180 to have serviced, before any parts/extra work needed. Heat pump will cost £108 a year will contract from energy supplier.

We have a gas hob but would like to replace it with induction. We'd like to redo the kitchen in 2-3 years but not right now. We are saving for this and will DIY it. We could get an induction hob to replace the gas one, most can be plugged in or hardwired so we might wait until we redo the kitchen to hardwire it. Then we could ditch the gas and avoid the £100 a year service charge. Our energy supplier would cap the gas and remove our meter for free.

Any useful info would be good. You mentioned that the water pressure is good, so I am assuming the hot water tank somehow manages the pressure to send water upstairs. Our showers on the 1st and 2nd floor rely on high pressure hot water to work as they have no pump and we don't want to change all of that.

We're also worried about being cold, or our energy bills going up to keep the house warm enough.

Final thought is that if they cost this much, we are wondering if it would it cost £10000 to replace in 15 years time? Or if prices would go down and only the actual heat pump unit would need replacing which would make it cheaper. Obviously this would be much more expensive than a replacement boiler in the long term. However, it might not be possible to get a new gas boiler in 15 years, in which case having the rest of the systen set up would be better.

Any advice would be really welcome. Thanks.

We had someone round after initial quotes online.
Turns out that our house would need addition radiators which effectively means redecorating the whole house! I feel the cold easily and was told that a couple of extra electric radiators to boost the heat as they will never get up too the same temp as with a gas boiler.
We've decided that technology isn't good enough at the moment for us to have a heat pump.

We have an air source heat pump and a combi boiler, apart from hot water we do not use the boiler, heat pump is far more effective in both heating and cooling the house, yes it costs more to run but is only used for a maximum of 20 mins at a time, would not want to do without it now.
Shop around, know prices of units etc, we had ours installed by a great local business (4 internal wall units + outside main unit) for less than 4.500. BUT we were in the process of renovation at the time so it was much less disruptive than having one retro fitted to an occupied home.

This. We live in an older house and asked our plumber about heat pumps when it became clear we needed to replace our boiler. He advised against it. He said that they were very inefficient in anything other than new builds, given the levels of insulation, double/triple glazing etc.

@CheshireCats @DougMLancs @kwetu how hot do your radiators feel?

I don’t want to replace ours as they’re not that old and the anthracite ones to match the decor but I know it’s recommend to have specific types.

But we don’t currently put them on unless it’s below 12 degrees in the house so even on the equivalent of 3 or 4 would be a massive treat for us.

Some things I would say :

i) Yes the increased government grant makes heat pumps more attractive.

ii) Your house does seem "generally" suitable for a heat pump as it should be relatively low heat loss being of modern build an a mid terrace.

iii) You won't really be able to run a heat pump the same way you run a gas boiler. Heat pumps are lower power, so you tend to leave them on all the time rather than switch them off during the day. This means if you want to save money you tend to run the house at a lower average temperature all the time (say 17C) rather than have it at 15C during the day when you are out, then at 20C for the few hours at night and in the morning when you are in by turning on the gas. This may/may not suit your lifestyle.

iv) Your pressurised system seems a bit unlucky. £500 is a fair cost for a part. I certainly don't service mine once per year and it is 20 years old, I think once every two/three years would be fine. The systems in general are built to a very high standard (because they are pressurised). I have my boiler serviced once per year, but that is only £100. what part failed on it ?

v) Replacing the gas hob, not sure whether this makes sense. It will probably be about £300 to buy and replace the hob (guess). If you use 2 burners for 0.5 hour a day that is 1kwh of energy, that would save you 25p a day in gas vs. electric (as gas is 3x the cost of electric), so pretty much the same you pay as the gas service charge.

vi) I don't know where the pricing/taxes will be in 20 years time. No one can predict that. There is a general move to move away from gas to electric and the government will achieve this somehow, probably through a process of subsidising heat pumps and penalising gas in some way. The only thing you can be certain about is that they won't announce a £100 a year gas boiler tax in the run up to an election.

vii) I don't know how heat pump hot water systems work. But generally I think the cylinders are placed in close proximity to the pump, so you are right, you will need pressure to get to the top floor. I don't know whether they are pressurised or not.

viii) When you say "radiators replacement" what does that actually mean ? For example many modern builds use microbore plastic radiator pipes. These are small pipes that do not allow much water flow to reach the radiators. For a heat pump system you generally have lower temperatures and higher flow rates for the bigger radiators. This may mean that you need to replace the microbore pipe with larger diameter pipe. This could be expensive as in new builds the pipes are embedded in the walls.

Good luck !

Ours are all now double panel and double fin types and our system is designed to not need any hotter than 35C water going in so just below body temp. We chose to upgrade the rads to achieve this for maximum efficiency (no redecorating required as they were the same footprint just more panels/fins). A common design temperature for fewer rad upgrades is 45C which would mean quicker temperature changes but slightly lower efficiency. We also kept our microbore pipes and we’re a standard 1960’s semi with cavity wall insulation. My brother in law also has one in their Victorian solid wall end terrace so the assertion put out by some plumbers that you need a super insulated, 3G house is just false. Octopus Energy have released their own range of air source heat pumps (6kW from Dec and larger models to follow) that can match boiler flow temperatures and will use a bespoke tariff to help keep running costs down. You could then upgrade dads and lower the flower temps piecemeal to reduce initial capital outlay.

It’s not false , if a house is leaking heat as fast as a heat pump puts it in ( or leaking faster ). Then the house is never going to be warm. Unless you whack it right up and then it costs a fortune to run .

the good thing about a gas boiler is you can just have it on when needed and it will heat up quickly. Then turn iit off when not needed.

a house needs to be well insulated for a heat pump to run effectively and efficiently.

Insulation is the key to any form of heating whatever it runs on.

@GasPanic, thanks so much for your in depth reply. Lots to consider and ask questions about.

Regarding the pressurised system issues. We developed a leak of hot water from a valve close to the water tank. It was replaced but then occurred again. The plumber discovered that the balloon thing (don't know technical term) has collapsed and was creating issues with the valve. So the balloon thing had to be replaced and a second new valve fitted. Tank needed draining and whole thing was very time consuming. Plumber now likes to test this along with the annual service and make sure it is OK.

Sounds like you were unlucky with the pressurised system.

With the megaflo system a lot of plumbers seem to think they are good for 25 years plus. They are supposed to be serviced once a year I think, but I doubt very much that most people do that (when I asked my ndn they said they had never had theirs looked at in literally decades!) and I certainly wouldn't do it once per year. I have had the pressure/temperature release valve replaced on mine when I moved in because I thought 20 odd years was a bit of a long time to go without having something that essentially has to work serviced.

Maybe you don't have a megaflo (integrated expansion tank). When you buy a new build builders do tend to put the cheapest crap they can in, because very few people buy a house on the quality of the hot water cylinder or boiler. I had an Ideal Standard boiler when I moved in (it lasted about 17 years) and it was pretty much on its last legs and clearly was not an expensive and well built model, but I know people that have Worcester Bosch who have had them 20 years plus with nothing going wrong on them.

Anyway, TLDR is I would say that £200 a year keeping your current system serviced is a bit excessive. Other peoples opinions may differ :)

Thanks for this info. We are with Octopus for gas/electric and our quote is from them. It says it would include any necessary replacement radiators. Obviously that depends on what they consider necessary. I wonder if the system might be better with newer bigger radiators but if the consider existing ones adequate, despite being less efficient, they might not be included. These are the kind of questions I want to ask. I think the quote was for a Daikin heat pump, so not sure if that is something different from the own brand you mentioned. Do you have any info or link to the Octopus own brand heat pumps? Is this something to do with RED that they have taken over?

@DougMLancs, found this article:
www.power-technology.com/news/octopus-energy-unveils-3000-heat-pump-system/?cf-view&cf-closed

That’s the one @Netcam , the Cosy 6 (and Cosy 9, Cosy 12 in future) is the ASHP they’ve been developing with RED- they aren’t quoting for the Cosy 6 until December but they have said it will be cheaper than their current quotes with Daikin. If your heat loss says you need larger than a 6kW ashp then you’ll have to ask them about expected release dates for the larger models.