Boiler alternatives

thanks for the replies, might help if I put the floor plan to show what the restrictions are.

currently the combi boiler and gas supply sit on the inside of the external wall in the kitchen, the kitchen will be a converted to a bedroom.

there are only three radiators, so not a big demand but the ceilings are 2.8m high.

the kitchen will be put in to the main room up against the wall. I've crudely drawn this in.

it will be for a rental so doesn't need to be fitting my needs as such but I do want it to a good standard for anyone living there, meet or exceed epc standards, etc

part of not having gas is to take out the carbon monoxide risk, needing to get it checked every year etc but mainly to make better use of the space and make the kitchen a bedroom.

the only thing I can think of here is to remove the gas and convert to electric. but I have no experience of electric boilers in this situation.

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I'm also buying a flat with a trashed gas combi boiler and have looked into it a bit, as I've really like to move away from gas too.

My understanding is that gas is still the most cost and energy efficient, but electric boilers may not be a lot more expensive for small flats. You might find that costing out the expected use scenarios might make electric attractive maybe?

I've disregarded air source heat pumps because everything I read about them is unconvincing or bad, especially the fact they're noisy. I would like to be wrong on that obviously.

One thing I'm interested in, is hydrogen ready gas boilers. Bosch have demonstrated that current gas boiler tech can be made hydrogen ready, but they're unlikely to be ready for a while, and then hydrogen will be a 5-10 years away on top, if at all.

ceres power.
but i guess they don't have a product yet. but soon, i think.

edit . i guess i'm a bit behind the times and they appear to have abandoned this idea a few years back in favour of larger CHP applications.

especially the fact they're noisy

The noisy part is outside. There should be nothing but radiators and maybe a storage cylinder inside. Maybe you're thinking of the kind that transfer heat directly to the air and therefore have a fan indoors?

I think ASHPs are still in early adopter expensive-for-no-good-reason stage. I expect that to change though it may take a decade or two.

Hydrogen should be considered bollocks vaporware until proven otherwise. The boilers are the easy bit.

Maybe you're thinking of the kind that transfer heat directly to the air and therefore have a fan indoors?

I'm thinking of pumps which make noise anywhere, inside or out. Imagine living next to flats with an array of heat pumps outside randomly spinning up at all hours. Gross.

I'm having a loft conversion on my flat and taking the number of bathrooms from 1 to 3. The exisiting small combi boiler is quite new and in decent condition plus I would like to reduce the reliance on burning gas so would it be possible to add an immersion tank to the system? Most of the time only one shower would be used at a time so the existing combi would be fine, then the idea would be to switch on the immersion if people are coming over. Is this a silly idea?

I thought about an electric boiler earlier this year when my old gas one died. They have advantages as they don't need a flue for the combustion gases so can be put anywhere but they do need a high amp circuit to be installed.

I did a cost comparison and they are too expensive to run unless you have PV solar already
or currently use heating oil.

I went for a new gas boiler that can be converted to hydrogen in the future.

Air heat exchangers are reliable now but are far more efficient with underfloor heating.

presumably 16amp won't be enough then?

No, they are pretty hefty. 45 to 50A minimum which, on a small house or flat will take most of the suppliers main fuse capacity.

Even a 7kW electric shower is advised at 32A with a 6mm cable.

would you recon the flat in the floor plan above, 35sq meter, 3 radiator tiny flat, would be alright on an electric boiler? I can see how on a house it wouldn't work but hoping it would be a relatively negligible difference on something so small

Electric Boilers are designed as 'like-for-like' gas boiler replacement.

I doubt any one makes them that small at the moment. Even gas boilers will be minimum 2 bed, 1 bathroom, 5 rooms with radiators.

There isn't a lot of choice on the market as no one really buys them, classic lack of demand. 🤷

No matter what the size of the flat you'll spend more on electricity than you would running a gas boiler.

Gas boilers modulate no matter what size the property, it'll heat fast and for that size you'd get away with a wee boiler.

Electricity costs about 5 times more per kWh than gas. Whether that’s affordable or not depends a lot on how well insulated the flat is, how much heat you’ll get from neighbouring flats, etc.

If you’re committed to electric, for three radiators you might as well junk the lot and install wall mounted heaters.

If you’re committed to electric, for three radiators you might as well junk the lot and install wall mounted heaters.

Very much this, especially if the flat has a E7 Tarrif option. Electric shower and a unvented instant boiler for hot water at the kitchen and bathroom sink?

Still. A pain in the arse and a lot of plumbing and new circuits.

We had someone round for heat pumps, there's a big govt. push for them in France.
The general impression was that they are efficient for new house builds, or with full conversions to under-floor heating, reverse cycle air-conditioning and the like, but not so much for existing houses full of radiators. They are more efficient the more they are exposed to sunlight, which tends to be out front, but no-one wants to see one out the front of their house, so they mostly get installed at the back, where they get less sunlight and are less efficient, and therefore require more electricity to run. They do make noise outside - how much noise depends on size, quality, etc, though the guy did admit it's a bit comparable to an air-con fan.

Coming to London soon...

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though the guy did admit it's a bit comparable to an air-con fan.

Same technology. Air Con have been heating/cooling units for years, just applied to single areas as they are mostly commercial.

Air Heat Exchange (Ground HE even more effective) tech is well understood. Just its only recently being applied to whole home heating.

Had a couple of people asking for radiators in rooms that have modern AC units. They are always surprised when I show them how to turn the AC unit to heating via the remote control.

Coming to London soon...

Nope. London will be underwater by that time. 😂

But seriously. This is something that will happen.

Air Conditioning will get more and more essential. For large flat blocks it'll be more efficient to have large AHU's on the roof and duct it to individual flats.

Yeah, right... Individual flats will have to buy their own system.

F-Gas engineers with Cherry Picker / Scissor Lift tickets will make a killing.