New boiler...gas or hold out for heat pump?

If you think Patrick Harvie will get his way then it's a no-brainer. So far I'm seeing estimates of £10-15k for a HP and £3-4k for a gas boiler. I'm also aware that many HP owners locally find them insufficient during the Winter, though that might be less of an issue for you in the sunny South 😉

Gas

I'm a big fan of heat pumps in principle and when they don't work, I'm happy to believe that it's poor system design. After all, the Nordic countries make them work.

They will also save a shed ton of CO2.

The problem is, right now, it doesn't matter what you spend on the system, you'll struggle to see payback unless you're also generating a substantial excess of electrical energy.

Fit a gas boiler and try to get the system ready for heat pumps by fitting underfloor heating and/or giant radiators and run the system at a lower pressure.

The extra you might have spent on the heat pump, have a look at using that money for batter solar.

There was another similar thread recently but replacing an oil burner.

I think the general consensus was you need to insulate your house before even thinking about HP

They're not quite there yet imo, not in terms of the technology just the cost.

We got a fully funded a couple of years ago for an air source set up. There was no way it made any sense, even whemn free as our house isn't suitable being a detached 30's Edinburgh bungalow with converted attic. The dude even told me it would cost more to run than our current gas set up, would also provide less heat.

In my ideal world i'm holding out for some form of synthetic gas replacement wonder chemical they can use the existing infrastructure for or something else magical.

IMO quite a balanced decision.  If your house is well insulated I would go for the heat pump.

You need to have a well insulated house. Additional cost can be more easily justified if you also have solar and storage.

I read if you can drop your boiler flow temp to under 50 degrees and your house stays warm then it is insulated well enough to go down heat pump route, not sure how accurate that is though.

Additional cost can be more easily justified if you also have solar and storage.

You'd need a lot of solar panels to run the system 24/7 in the depths of winter. We can't even manage to run the house most days in Dec/Jan and charge the battery at night off the grid, which is when you'd be wanting the most heat from the thing.

The next Gov might get serious about the environment and roll a plan out.......

Until then, gas 😔

The insulation levels of the house will affect any type of heating.
If you need 20kw to heat your house because of poor insulation then you can still use a heat pump, but you need to make sure that the system is designed to deliver it. Other fuels with higher flow temps will get round a badly designed emitter system, a heat pump won’t. But you can use a heat pump to heat nearly any property.

I had an epc on a 60s detached bungalow, chap said I d be wasting my money on a heat pump, South facing and lots of glass too.  Told me to insulate roof and underfloor, as have access.  Gas boilers coming to end of life so looking at alternatives.

<li style="text-align: left;">Also in need of a boiler so I enquired to Octopus about the grant and prices. I needed a new EPC before anything could be done. After speaking to the EPC guy he said absolutely no chance of it working on my 70s detached house. Basically it's not designed to work properly without a load of extra insulation and you are going from a cheap fuel (gas) to the most expensive (electric). He also said that he was going to court for a few people where the system was unable to work properly and the supplier has basically lied to them about it's efficiency in their house. So I'm staying with a gas combi until they work better and I don't need to extend the house to house all the equipment.

The consensus seems to be that the house really needs to be designed with heat pumps in mind, otherwise it's a massive cost, and you won't save any money. Giving times are hard, getting a nice efficient new gas boiler is the answer, and possibly improve existing insulation.  You'll cut your energy use anyway !

a regular boiler with water tanks in the loft,

So what tanks in the loft? A heat pump will need a 'hot water tank' - they're not on-demand heaters, so you'd not get rid of that.

If you are based in Scotland you can get generous grants and interest free loans.

To improve your whole house based on your EPC.

https://www.homeenergyscotland.org/funding/grants-loans/

Solar PV excluded now as price has come down and demand is high.

Even if you still go with a combi, there may be funding for you.

1) look up your EPC for free here (Scotland only

https://www.scottishepcregister.org.uk/

2) call home energy Scotland.

I used them to get a gas connection, central heating installed, new combi boiler and cavity wall insulation. Currently paying back 55 quid a month on interest free loan.

https://www.theguardian.com/environment/2023/jul/25/gas-boilers-heath-pumps-gove-government-green-policies-ban-new-petrol-diesel-cars

Wait a minute, looks like the Gov have realised they've made a dog's dinner of heat pumps.......

..and the ban on new diesel and Petrol cars from 2030 is 'immovable'

Pretty much guarantees that'll be 'reviewed' then 😀

I'd hold off on the heat pump because after the possible news of a turnabout over banning fossil fuel cars etc, might find any legislation over this might also end up, if you pardon the pun, on the back burner, at least until the country recoups a bit of money after the horrors of brexit and the pandemic and inflation and interest rates become more stable.

Like the ULEZ etc, this is a vote killer, so I dont think any party is going to implement it with legal backing, especially the SNP who have had too many recent problems to risk it.

I read if you can drop your boiler flow temp to under 50 degrees and your house stays warm then it is insulated well enough to go down heat pump route, not sure how accurate that is though.

If you can turn your boiler down this far or closer to 42-44°, this is a really good guide as long as you remember to allow the programmer to call for heat whenever it needs it 24/7.

Pretty much guarantees that’ll be ‘reviewed’ then 😀

At the rate they are being dropped I doubt many major car makers will be making petrol/diesel cars by 2030.

Sorry to thread hijack - but I'm trying to workout the calculation for the heat pump in the French Alps. I've not been in the 45m2 apartment for a Winter yet but it can in theory get down to -20. Is there a way I can calculate the demand myself based on the m3 of the property and window sizes and insulation? I'm popping 80mm kingspan on all internal walls and it already has underfloor heating that is run from an oil boiler (which I want to get off). If I can't work it out I'm going to go this route as I think its still cheaper than oil: https://www.electric-heatingcompany.co.uk/shop/product/slimjim-4kw-electric-flow-boiler/

Thanks!

Heat pump here as no gas supply and house is new. Id say if you can’t run house on 40c supply temp for a 0c outside temp you are going to struggle. That’s before oversized radiators are fitted either.

Our house is state of art insulation and I can run with oversized radiators at 33c supply for 0c outside. Heat curves aren’t straight and as outside temp drops it becomes more expensive to extract the heat from the air. Below a certain supply temp point the system will employ an immersion heater to maintain the supply temperature and it then becomes hugely expensive (circa 2.5x kWh).

If I was you I’d wait until winter and see if you can adjust supply temp but leave system to circulate continuously to test efficiency of house before committing.

I think go with Gas there is not much positive news about Heat Pumps - Advise from colleague energy costs more and house is not warmer.

The suggestion that gas boilers might be banned but not coal and oil heating seems mad to me. Especially when the gas in the network is becoming less fossil-y with AD Gas (now)/ Hydrogen (soon) being added. It smacks of something not very well thought through. In very rough terms coal is nearly 100% carbon and gas 20%ish carbon.

It smacks of something not very well thought through. In very rough terms coal is nearly 100% carbon and gas 20%ish carbon

But then you include the gas leaks and venting in its extraction and production and the higher warming potential of methane, along with coals sulphur emissions which are cooling and it turns out to be almost as bad as coal for emissions

Heat pump. Unless the price difference is important to you.

The planet won’t cool itself.

Running costs will likely be similar to GCH unless you change your house insulation.

Unsure why folks think that a heat pump will reduce heating costs with no other changes: you’ll still need the same amount of heat put in your house in the same time to keep the same temperature.

Revisit the 40C and 50C thinking. Modern HPs from Vaillant and others will function OK at 60C and up to 70C.

add some money to get an unvented big tank.

Avoid a combi.

The suggestion that gas boilers might be banned but not coal and oil heating seems mad to me

Oil is to go, it was going to be this year, but iirc, has been put back until 2025. Thats no new oil boilers, or replacements to be fitted. Old ones can be repaired.

Coal was the first in line, it changed a few years ago, only smokeless coal is now available, at around 50% more cost compared to coal. Very few people use coal as their main source of heating, in the last 10 years, I’ve only been to one house that still has a coal boiler.

Unsure why folks think that a heat pump will reduce heating costs with no other changes: you’ll still need the same amount of heat put in your house in the same time to keep the same temperature.

...because energy is used in the heat pump to absorb heat outside and reject it inside. So a compressor, used to move the "heat", rather than burning fuel (or electrical resistance) to generate the heat. Sounds mad, but you get more heat out than you put in as electricity. Electricity is more expensive per hWh than equivalent gas though, so it's a balance.

because energy is used in the heat pump to absorb heat outside and reject it inside. So a compressor, used to move the “heat”, rather than burning fuel (or electrical resistance) to generate the heat. Sounds mad, but you get more heat out than you put in as electricity. Electricity is more expensive per hWh than equivalent gas though, so it’s a balance

Yes. That is how a heat pump works.

And I think by saying ‘it is a balance’ we are in agreement: for a given output a heat pump is more efficient than a boiler but electricity is more expensive than the gas.

For example, if you need 3,000W to heat your house then you need 3,000W. you could get that by burning some volume of gas at about 80% efficiency. Or you could get it by extracting that from the environment at up to 400% efficiency with a heat pump. You still need 3,000W to heat the house. How you get it is the question here.

I’d go heat pump. With no other changes it will not save running costs but it is a better environmental choice.

@prettygreenparrot sorry, was seemingly teaching granny to suck eggs there. Genuinely thought it was a question 🙂

The HP debate has been going on for some time now. I'm even toying with fitting one myself, but......

The deal breaker is:

• All up Installation cost

I have ran my heating system at low flow all last winter with good success, so I'd be confident that i could install and achieve a COP of 3.

The problem to me is that electricity is 3 x the cost of gas, so the running costs would be the same. To get an improvement, the HP would need to use electricity that it's cheap on a HP tariff. This would then need the HP to run at limited times and therefore require it's heat storing for use in the day time. Then i think it would work for me.

But I've got my annual gas use for our 4 bed, 4 person house down to 8500kwh/yr.

It would take me a long time to get my install investment back. The gov needs a bigger grant before I'm likely to budge.