WFH: Convector/oil heaters vs GCH?

iamparakeet

I'm in your standard three-bedroom Victorian terraced home with combi boiler. No house thermostat, only on-boiler dials.

Upstairs bedroom #3 is a long-time home office, and now also downstairs reception #2 since last year.

In the last couple of years, I replaced all our radiator theromstatic valves with rudimentary smart valves. Basically, they have timers and Bluetooth control. My strategy has been to leave the boiler and GCH on (except overnight) but turn off all bar two radiators, believing this will save money. I assume the boiler then needs to create less hot water to send to radiators around the house.

Q1: Is this really how it works? Over the last three years, my annual energy bill has stayed flat (which I think is the new up).

Q2: How would you weigh this approach against an electric/oil convector heater in both rooms? I am reading a couple of articles (ThisIsMoney, ChangeWorks) that pass on this advice - it's cheaper to use GCH than electric.

This MoneySavingExpert article (updated Sep 7) similarly says: "Usually, it's best to use your central heating to heat your home rather than relying on electric heaters, especially if you have gas central heating, according to the Energy Saving Trust. If you're only using a couple of rooms, you can use thermostatic radiator valves so that your central heating isn't heating empty rooms. Electricity is much more expensive than gas, so using electric heaters can ramp up your energy bills."

It also says: "The Energy Saving Trust says electric heaters are one of the most expensive forms of heating. It says the cheapest way to heat your home is by using an efficient gas central heating system, with a full set of thermostatic radiator valves, a room thermostat and a timer."

That's now multiple sources.

Q3: Now, does the current energy industry issue change any of this? Is there a point at which it is becoming more cost-efficient to use the convector heaters?

Thanks.

QrizB

Mains gas is between 1/4 and 1/5th of the price of electricity, per kWh. It is very unlikely that heating your home electrically will cost less than running your gas central heating.

matelodave

Depending on your tariffs, gas is around 4-5 time cheaper than leccy which means that, for the same amount of heat, an electric heater will cost 4-5 time more than gas. Even if the efficiency of your gas heating heating dropped to 25% by only heating one room you'd be hard pushed to break even by using leccy.

Intuitively it does seem that running a convector or oil filled rad in one room rather than the whole central heating might work out cheaper but it's probably only marginal if it is.

The only way to find out is to do you own experiments - run the heating as you would for a week - carefully recording your consumption at the beginning and the end of the week, then shut off the heating and use leccy for a week, again recording the consumption for comparison. You also need to check the outside temperatures and keep the room temperature the same as you would to get a fair comparison.

Reed_Richards

What happens when both the radiators that are on reach their set temperature?  The water being pumped round your central heating has nowhere to go.  A well-plumbed system will have a bypass somewhere that activates when the pressure gets too high and then the hot return water causes the boiler to shut off for a while.  Older or badly plumbed systems may not have this and the pump can be damaged trying to pump water that has nowhere to go whilst the water inside the boiler overheats until a safety cut-out activates.  Either way I would have thought it must lead to inefficient use of your boiler.  I would put a room thermostat in the room that warms up the slowest and set the radiator valve to its maximum setting in that room.