Oil-filled radiator finally competing with gas central heating for one room?

martin100x

Good afternoon,

I've seen a few posts comparing the costs of an oil-filled radiator vs gas central heating and the central heating always seems to work out cheaper. However, I wonder if an oil-filled radiator can now compare with gas central heating for heating a single room, if using a night-time electricity rate. I'm using the night-time rate because I have battery storage, and store electricity overnight.

To heat a single room that is 15m squared, I understand that a 1.5kW heater would be required. At the night-time rate of 7.5p/kWh, this would cost 11p per hour if it was going full blast all the time, or just 6p per hour if it clicked on about half the time.

I have a 33kWh combi boiler. Today I clicked the central heating on for an hour and noted how much gas was used (via the outside meter). I believe the gas use for one hour was 7.2kWh. At a rate of 10.3p/kWh for gas, this is 74p per hour.

11p per hour for oil-filled radiator vs

74p per hour for central heating.

No doubt I would use less gas if I turned off some radiators, and I'll need to do this and measure the hourly gas use again. However, unless the gas use decreased greatly, to around 1kWh, the oil-filled radiator is cheaper to run. Is that correct?

EssexHebridean

How much gas would you have used if you had only been heating the single radiator in the same room used for the Oil Filled Rad part of the experiment? It feels to me as though currently your comparison is heating one room with an oil filled rad -v- heating a whole house with GSH. Also, was the same temperature reached inside the hour using both methods? 

Astria

If your GCH used 74p/hour then yes, but typically it will only use it for the first hour to bring the property up to temperature, and then substantially less afterwards. You could do with doing it over a longer period like a day. The chances of having 2 identical days are slim but it would give you more of a ball park figure.

For example, my heating last year (it's not come on yet this year) was on for about 10 minutes per hour.

How big is your battery?

k_man

Electric heating is (virtually) always more efficient than gas heating.
So with like for like, if electricity is cheaper or the same (per kWh) as gas, as it seems to be here, the electric would be cheaper.

This assumes that this use of battery doesn't displace other usage onto daytime rates, and that battery loses are included in the 7.5p rate.

I suspect both these 2 assumptions are incorrect.

victor2

martin100x said:

Good afternoon,

I've seen a few posts comparing the costs of an oil-filled radiator vs gas central heating and the central heating always seems to work out cheaper. However, I wonder if an oil-filled radiator can now compare with gas central heating for heating a single room, if using a night-time electricity rate. I'm using the night-time rate because I have battery storage, and store electricity overnight.

To heat a single room that is 15m squared, I understand that a 1.5kW heater would be required. At the night-time rate of 7.5p/kWh, this would cost 11p per hour if it was going full blast all the time, or just 6p per hour if it clicked on about half the time.

I have a 33kWh combi boiler. Today I clicked the central heating on for an hour and noted how much gas was used (via the outside meter). I believe the gas use for one hour was 7.2kWh. At a rate of 10.3p/kWh for gas, this is 74p per hour.

11p per hour for oil-filled radiator vs

74p per hour for central heating.

No doubt I would use less gas if I turned off some radiators, and I'll need to do this and measure the hourly gas use again. However, unless the gas use decreased greatly, to around 1kWh, the oil-filled radiator is cheaper to run. Is that correct?

Unfortunately, not even close to correct. Above posts suggest why.

As also said, how big is your battery? You would need enough capacity to run your 1.5kW heater all day, even with it switching off as temperature was reached, just as your GCH would.

funny.money

I remember speaking about this exact same situation last Winter.  We live in a large 5 bedroom house,  large sitting room and conservatory. We turned one small upstairs bedroom into a cosy snug and heated it with an oil filled radiator.  Apart from the cost question,  I found the idea of heating a huge house, when we basically use one room in the winter with occasional trips to the kitchen to make a cuppa, just 'not right'. But reading the above, would we be better off turning every single radiator in the house off, except for the one in our snug?

ariarnia

i was thinking about this after posting about my radiator in my home office. i dont try to heat the hole room. just the space under my desk. and i can see its more expensive but i was thinking it was actually maybe quite a complicated sum really. to complicated for my brain definately  

you can turn off (or down) the other radiators but would need to allow for loss in the pipes through the house to the room being heated the same as you would need to allow from loss charging and discharging the battery. and i think i read condensing boilers are less effective if theres not a decent drop in temp between the in and out so you'd want at least some heat loss.

but also i wondered about the 1.5kw radiator thing. do you really need that size or is it like boiler temps. a smaller radiator would eventually heat the space just slower the same as a lower boiler temp would heat the house but slower. but does that even make a difference with electric as its 100% energy to heat?

and thats not even thinking about the heat loss in the room. an electric radiator when its off uses no energy and when its on all of the energy goes into the room but a radiator with hot water in the pipes would lose a little heat constantly from the system even when the room was at the desired temp. just with he water in the pipes cooling down (like not running hot water to wash your hands because by the time the tap is hot youve finished and all youve done is heated however many meters of pipe) so the 'topping up' maintaining the heat might be more efficient with the radiator...? 

the gas is still almost certainly cheaper than the electric but in a huge house with an old boiler and the room miles away from the boiler then i wonder how close it could get.

i really am over thinking this now  

martin100x

victor2 said:

Unfortunately, not even close to correct.

Okay, thank you, happy to be incorrect if it means avoiding a mistake. So gas central heating is much cheaper than the 11p per hour for a single room?

We only tend to have the heating on for a few hours a day at most. We haven't really had the heating on so far this year, for example.

markin

Even without the night rate or battery its around 30p vs 70p for the first hr.

QrizB

martin100x said:

victor2 said:

Unfortunately, not even close to correct.

Okay, thank you, happy to be incorrect if it means avoiding a mistake. So gas central heating is much cheaper than the 11p per hour for a single room?

No, that isn't correct either.

On a per-kWh basis, electricity at 7.5p/kWh is cheaper than gas at 10.3p/kWh.

victor2

QrizB said:

martin100x said:

victor2 said:

Unfortunately, not even close to correct.

Okay, thank you, happy to be incorrect if it means avoiding a mistake. So gas central heating is much cheaper than the 11p per hour for a single room?

No, that isn't correct either.

On a per-kWh basis, electricity at 7.5p/kWh is cheaper than gas at 10.3p/kWh.

But that is disregarding the efficiency lost in getting the cheaper rate electricity into a suitably sized (ie. expensive) battery, to be held and subsequently released when required into the heater. GCH isn't cheap, or 100% efficient, but is capable of heating the entire house, where the battery won't be.