Heat pump when dont use much hot water

barker77

I currently have a standard gas boiler and hot water tank.

I live on my own and typically have a shower once a day, and wash up once a day. I am thinking of getting a dishwasher soon so will use even less.

Every other week my young son stays with me for a week so has a shower every other day and sometimes a bath. I am thinking of replacing this setup with either a combi boiler or heat pump but wondered if it would be lots cheaper to run (not install as expect heat pump initallly more outlay) to run but keen to understand if anyone is in a similar situation to me and can give an idea of costs or what you do?

jackieblack

Personally I would never give up my hot water cylinder. I’ve had a couple of occasions when my boiler broke down and being able to still heat water via the immersion and get a hot shower was the only thing that kept me going.

But everyone is different 

Rodders53

If it ain't broke why change what exists?  It'll almost never pay back the installation costs due to energy savings alone.

Boiler:  Natural gas?  Sealed or open vented with a feed/expansion tank ?  How old (is it condensing)?
HW tank --- open vented or unvented (so mains water pressure)?

Any gas boiler with HW cylinder can heat the cylinder up within 30 minutes to an hour so just have it on a timer to heat for your daily and switch on manually for an hour when needed for a bath.

Electric heat pumps still do not save money cf gas, nor even Kerosene and bulk LPG.  They are getting closer to the same cost where the homes are suitably super-insulated.

Modern gas boiler may use a bit less gas cf an older one... Do your own guesswork -- a 20% reduction in gas per annum compared to the install costs and upheaval involved.

tacpot12

replacing the existing boiler with a combi boiler is likely to give you the cheapest running costs, but the cost to change will be about £3,500, so you will have to save a lot to pay for this. It would be better to start saving now so that you have the money to replace your current boiler when it fails and cannot be repaired. At that time, you can evaluate whether heat pumps have come down in price to the point where they cost the same amount to install as a gas boiler. 

FreeBear

Rodders53 said: Electric heat pumps still do not save money cf gas, nor even Kerosene and bulk LPG.  They are getting closer to the same cost where the homes are suitably super-insulated.

Modern gas boiler may use a bit less gas cf an older one... Do your own guesswork -- a 20% reduction in gas per annum compared to the install costs and upheaval involved.

A super-insulated home is not a prerequisite for a heat pump - Regardless of heat source, insulating (and draught proofing) a house will cut energy consumption. As for a heat pump being more expensive to run, yes, if they are poorly set up, running costs will be higher. However, looking at heatpumpmonitor.org, there are a few people getting heat for less than the current cost of gas.

As for a modern gas boiler returning a 20% saving in usage, that would depend on just how old the boiler is. I had a vintage Baxi back boiler. Turning the gas off during summer months to avoid having the pilot light on 24/7 saved ~1000kWh. Smarter controls that varied the temperature throughout the day/week saved another chunk of gas. Fitting new windows along with IWI & more loft insulation cut gas consumption even further. Went from ~8000kWh down to ~3500kWh. A new combi boiler was fitted last summer, and I haven't really had time to tune the system and collect sufficient data. But it looks like I might be getting around 10% saving - Last winter was fairly mild, and I had been using the stove to provide a good proportion of the heat. If it wasn't for the fire, gas consumption would have been much higher. If I had waited until this year, I may well have gone for a heat pump rather than a gas boiler (installation costs would have been very similar). Getting rid of the gas meter would be an instant £100 per year saving. Switching to Octopus Agile or Cosy would reduce running costs even further.

Reed_Richards

Rodders53 said:

Electric heat pumps still do not save money cf gas, nor even Kerosene and bulk LPG.  They are getting closer to the same cost where the homes are suitably super-insulated.

I don't imagine @Rodders53 actually owns a heat pump.  I have an owned an  ASHP since Dec. 2020 and mine is a bit cheaper to run than the oil (Kerosene) boiler that it replaced.  You don't need your home to be "super-insulated"; mine certainly is not.  If you have a heat pump or a boiler running on natural gas, Kerosene or LPG then the better insulated your house, the cheaper any one of these will be to run.  There's nothing magical or cursed about a heat pump that requires you to have a super-insulated house.

That said, there is no such thing as a combi heat pump, so a combi gas boiler might well be the answer with the lowest running cost for the needs of the OP.

Rodders53

I don't have a HP and possibly will never have one in my lifetime.

I note the word "a few" used by the Heat Pump advocates (I'd almost suggest 'geeks' in that they are of the minority that fully understand them and their use in practice in their homes) that are achieving 'on par' with fossil fuels

The exceptions, of course, prove the rule.

Insulation will give a bigger payback than any new heating system and in a far shorter time.

DougMLancs

Rodders53 said:

I don't have a HP and possibly will never have one in my lifetime.

I note the word "a few" used by the Heat Pump advocates (I'd almost suggest 'geeks' in that they are of the minority that fully understand them and their use in practice in their homes) that are achieving 'on par' with fossil fuels

The exceptions, of course, prove the rule.

Insulation will give a bigger payback than any new heating system and in a far shorter time.

If you look at the data, actually there’s not much difference between ASHP and going super insulated in terms of bill savings. Massive benefit in terms of emissions with an ASHP though. The biggest impact is actually solar and battery storage #FabricFifth https://lnkd.in/e7727qu6 

To the OP’s question, if you went for a heat pump install from Octopus or British Gas (quotes start at £500 but average about £3k) and used a smart tariff then I would expect running costs to come out pretty similar to running on gas. If you paid extra to upgrade more radiators it can be 40% cheaper than gas. Since you’ve already got a HW cylinder then that brings down plumbing costs a bit (though they still might want to upgrade the cylinder itself).