Electric Boilers: Fischer EB - happy customers? pricing?

ChaunceyGardiner

LessThanSte said:

i think i've seen some suggestion that electric is roughly twice as efficient as gas (dont quote me on that!), hence if electric is double the price the costs are equal...?

Electric isn’t even twice as efficient as an ancient back boiler. Modern combi boilers are up to 98% efficient.

[Deleted User]

Deleted_User said:

Well at the moment electricity is more than triple the price.

And I'd be very surprised if electricity for a boiler was twice as efficient as gas for a general water heating solution.  It might be true for a heat pump approach, but that's not the same thing.

It's quite a tricky one to assess. My unvented cylinder has been heated almost exclusively by solar from March through to now. The average kWh consumption on electricity this month is c.3kWhs a day. Yesterday solar output was very low, and gas prices were also low, so I reheated the cylinder using gas. Recorded consumption was 8kWh.

There appear to be a number of factors in play:

1.  I am not sure that the two thermostats are set to a matching temperature even though the set temperatures agree.

2.  When a gas boiler first starts up, the coil removes heat from the cylinder.

3.  The pipes to and from the boiler act as radiators.

4.  I have a small amount of heat leakage across one of the two zone valves and the radiator closest to the cylinder gets slightly warm.

5. Even the most efficient condensing boiler isn't condensing when it heats hot water.

In my case, heating the cylinder by solar diversion is a no brainer as I only get 4.1p/kWh for export. If I elected to get 15p/kWh for export, the choice of gas or electricity becomes more difficult. If I was to go on Agile Outgoing when export prices are high, then the pendulum would swing towards gas.

My options at the moment are limited as I am on an EV tariff - but future tariff choice is under review.

QrizB

Just reminiscing here:

Gerry1 said:

Welcome to the forum.

If you have gas (as cheap as 2p/kWh) you'd be barking mad to change to full price electricity at 13p/kWh or more.

Now gas is (almost) 13p/kWh and electricity is "only" 3x as expensive!

LessThanSte said:

Obviously, the green credentials are significant, and a big tick. More so if you've got solar power etc.

Direct electric boilers are barely any greener than gas.

If you burn a kWh of gas, you'll release 202g of CO2 while in 2019 the average kWh of electricity from the grid resulted in 193g of CO2 (figures here). The grid carbon intensity has fallen slightly since then (it's more like 180g/kWh now) but even so, that's only a 10% saving in carbon - and that's an average.

You can see live carbon intensity values here:

https://www.carbonintensity.org.uk/

Right at the moment, the grid varies from 0g/kWh in north Scotland (they've got lots of wind) to 367g/kWh in south Wales (almost all their electricity is coming from gas).

QrizB

wittynamegoeshere said:

I've met with a hostile response when suggesting my solution before for some reason...

I have an electric water heater that heats on demand, only when you switch the tap on.  Basically an electric equivalent of a gas combi boiler.

You've got an instantaneous water heater, something like this?
https://www.screwfix.com/p/ariston-aures-multi-electric-instantaneous-water-heater-9-5kw/741pp

That is very different to an electric combi boiler, like this:
https://www.screwfix.com/p/strom-sbsp15c-single-phase-electric-combi-boiler/655hr