ELECTRIC combi boiler suggestions

[Ric555]

Hi all,

I’m about to replace my boiler and have no idea what’s a good boiler or not as I’ve come across so many that all differ in price, soz, etc.

The place has no gas so it needs to be electric.

I will be adding central heating with this installation (probably 3 or 4 radiators incl. a towel rack).

It’s a one bedroom place (about 45m sq).

Any suggestions on size, make, price range, etc. would be greatly appreciated.

Thank you

 

[muggles]

You'll need 3 phase electric for a decently powered electric combi boiler. Do you have that?

 

[flameport]

Any suggestions on size, make, price range, etc. would be greatly appreciated.

None of them, they are all entirely inappropriate.
Wet central heating with only 3 radiators is nonsense.

3 or 4 wall mount electric radiators for the heating
80 litre or so unvented cylinder for the hot water.

 

[polesapart]

None of them, they are all entirely inappropriate.

+1

Storage heaters on E10 tariff worth a shout.
Likewise unvented cyl on E10 with timer with boost function,

 

[Ric555]

None of them, they are all entirely inappropriate.
Wet central heating with only 3 radiators is nonsense.

3 or 4 wall mount electric radiators for the heating
80 litre or so unvented cylinder for the hot water.

+1

Storage heaters on E10 tariff worth a shout.
Likewise unvented cyl on E10 with timer with boost function,

Thank you both; appreciate your responses. I also appreciate I could've given more context - I'm on the ground floor, so winters are colder, I also thought the radiators would retain heat longer and save electricity (as the assumption was electric heaters use a lot of energy) - do you think there isn't much difference in electricity usage?

@polesapart I've just removed a storage heater, albeit an old one, and I didn't find it that effective but perhaps it wasn't a good one.

 

[Ric555]

You'll need 3 phase electric for a decently powered electric combi boiler. Do you have that?

Thanks muggles, I'm not entirely sure - I'm trying to find out. I'm replacing an old electric one so assuming so?

 

[flameport]

do you think there isn't much difference in electricity usage?

There is no difference in electricity usage.

Heating a building to a certain temperature above the outside environment requires a certain amount of energy.

Wet radiators will remain hot for a while after the heat source is switched off.
Just as an oil filled radiator or storage heater would.
However they are not instant on, there is a significant delay between them being switched on and heat being emitted.

An electric convector heater does not remain hot after it's switched off, but it does provide heat instantly when switched on.

The only real differences are perceived heat for longer from the thermal inertia. However the energy delivered is the same.
Switching from one type of electric heater to another will have no effect on operating costs.

The only ways to save are:
1 - heat the building less, so it will be a lot colder.
2 - add more insulation so it requires less energy to heat it
3 - install heating devices which are significantly more efficient such as a heat pump - and for electric that is the only option.
4 - find a much cheaper fuel to use, which is why gas is so popular.


Forget about an electric combi.
With a 100A supply you might be able to have an 11kW boiler, which is the same performance as trying to fill a bath from an electric shower.
If it's a 80A or 60A supply (very common in smaller and older dwellings), then you are looking at something half the power or less, which will be totally useless.
Anything above 11kW requires a 3 phase supply, which you won't have and won't be able to get.

For comparison, a small gas combination boiler is around 24kW, more than twice as powerful. Most are 35-40kW.

 

[muggles]

Thanks muggles, I'm not entirely sure - I'm trying to find out. I'm replacing an old electric one so assuming so?
View attachment 313357

That's not a combi boiler, it's a hot water cylinder. Each of those elements is only 3kW and it's quite likely that they can't both be operated at the same time. By comparison the lowest powered gas combi boiler on the market is 24kW which produces acceptable performance for one outlet at a time, but is useless if you want to fill a bath

 

[Deleted member 267285]

Anything above 11kW requires a 3 phase supply, which you won't have

As I’m curious, how do you know this (I know you’ll know, so not insulting your intelligence - it’s because I lack it.)

 

[Ric555]

There is no difference in electricity usage.

Heating a building to a certain temperature above the outside environment requires a certain amount of energy.

Wet radiators will remain hot for a while after the heat source is switched off.
Just as an oil filled radiator or storage heater would.
However they are not instant on, there is a significant delay between them being switched on and heat being emitted.

An electric convector heater does not remain hot after it's switched off, but it does provide heat instantly when switched on.

The only real differences are perceived heat for longer from the thermal inertia. However the energy delivered is the same.
Switching from one type of electric heater to another will have no effect on operating costs.

The only ways to save are:
1 - heat the building less, so it will be a lot colder.
2 - add more insulation so it requires less energy to heat it
3 - install heating devices which are significantly more efficient such as a heat pump - and for electric that is the only option.
4 - find a much cheaper fuel to use, which is why gas is so popular.


Forget about an electric combi.
With a 100A supply you might be able to have an 11kW boiler, which is the same performance as trying to fill a bath from an electric shower.
If it's a 80A or 60A supply (very common in smaller and older dwellings), then you are looking at something half the power or less, which will be totally useless.
Anything above 11kW requires a 3 phase supply, which you won't have and won't be able to get.

For comparison, a small gas combination boiler is around 24kW, more than twice as powerful. Most are 35-40kW.

That's excellent, thank you so much for this explanation - really insightful - thank you.

 

[Ric555]

That's not a combi boiler, it's a hot water cylinder. Each of those elements is only 3kW and it's quite likely that they can't both be operated at the same time. By comparison the lowest powered gas combi boiler on the market is 24kW which produces acceptable performance for one outlet at a time, but is useless if you want to fill a bath

Thank you muggles - super helpful

 

[flameport]

As I’m curious, how do you know this (I know you’ll know, so not insulting your intelligence - it’s because I lack it.)

11kW is just under 50A, which is the maximum sized circuit breaker available for domestic consumer units without incurring other problems.

It would represent about half of the theoretical maximum current for a 100A supply, which assuming another 30A for other loads is around 80A, pretty much the maximum that would be wanted on any single phase supply.
Although a '100A supply' can theoretically supply 100A, it's not desirable to run them at that level for any length of time. Some DNOs are only providing a maximum of 80A fuses now due to high loads on for long periods like EV charging and electric heating.

Large loads like electric boilers require DNO approval before connection, and it's unlikely they would approve anything over 11kW or so on a single phase supply.
200A single phase supplies do exist but they are rare, in most cases once you need over 100A, it's a 3 phase 100A supply, which in theory is 3x 100A, but in reality is likely to be more like 3x60A.

For the OP, a 1 bed flat is not likely to have a 100A supply, 60A would be more likely.