How much does it cost you per day to heat whatever rooms you are heating

quartzz

If there are any other threads similar to this, please combine them etc.

I've now got some estimates in the new place after a few weeks of "required use", (taken from looking at the level of oil in my boiler tank, and saying "that looks about 1 inch less than it was X days ago"). I think I've been using approx £2 of oil per day (or 3L or so per day)

so just to say, 3 bedroom semi detached. poss well insulated but low thermal mass (heats up/cools down quickly). 5 TRVs (3 upstairs, 2 downstairs). downstairs 2 are on mostly constantly, 1 upstairs is on for 2 hours per day, other 2 turned off mostly. 1 towel radiator on low most of the time

also, about £1.80 daily electric at the moment (British Gas elec only)

carly

It's obviously pretty high at this time of year. Yesterday my gas used for heating a 3 bed detached house was £2.96.  we are both home all day, heating on continuosly from 8.00a.m to 9p.m. Thermostat in hall set at 17.5 on average.  We cook by electricity. one unused bedroom not heated

lohr500

Average 14.9 litres a day since 1st December. Big rambling old Yorkshire stone farmhouse conversion.
Heating hot water on Economy 7 electricity with a 2 hour oil heated boost at 19:00. The hot water setting also heats a radiator in the bath room which is handy when it is really cold outside..

15 litres a day at the price I just ordered = £9.40 a day  

In the summer it drops to less than a litre a day as we don't run the central heating and often zero if we don't need the hot water boost.

FreeBear

carly said:

It's obviously pretty high at this time of year. Yesterday my gas used for heating a 3 bed detached house was £2.96.  we are both home all day, heating on continuosly from 8.00a.m to 9p.m. Thermostat in hall set at 17.5 on average.  We cook by electricity. one unused bedroom not heated

3 bed semi (late 1920s build), in most of the day. Tuesday, had the benefit of solar gain so the house was at 19°C for most of the day. Boiler only ran for a total of 3hr40min, and got through ~25kWh of gas. Including standing charge, about £1.40.

Wednesday was a bit more costly - Boiler burned for 4hr40min and used 33kWh of gas (or £1.90 inc sc).

A couple of factors that render comparisons relatively useless - Gas boilers are generally modulating so a little more efficient than an oil fired one (most oil boilers can not modulate). I also use a wood stove to give the heating a boost on cold evenings, and the heat carries over to the next day. Oh, and my insulation levels are probably higher than other properties of a similar age.

quartzz

is the term modulating for a boiler, the same sort of thing, as using the term "inverter" for a microwave? (as in, it's not digital, but the power output actually changes)

lohr500

With a modulating boiler, the heat output of the boiler can be varied to suit the required output.
I am not an expert on modulating boilers, so hopefully someone can answer with more experience.

But as a simple example, when warming up a house from cold, the boiler may initially run at full output to heat up the house as quickly as possible. Once the house is up to temperature (usually set by one or more room thermostats), the boiler would reduce output to maintain the required temperature. Without modulation, the boiler would be cutting in and out at full power as the house temperature falls and then rises. My understanding is that by running longer at a lower output, this is more efficient than short bursts at full power. But I could be wrong.
I think more complex boiler controls may also take account of the external temperature and factor that into the modulation control.

As far as I am aware, there are only a few modulating oil boilers on the market . The vast majority of oil boilers do not modulate. When we replaced our oil boiler around 4 years ao, the choice of modulating boilers was even less and our installer was not a fan as he had 1st hand experience of reliability issues with one he had fitted a few months beforehand. Things may have improved since then.  

FreeBear

lohr500 said: But as a simple example, when warming up a house from cold, the boiler may initially run at full output to heat up the house as quickly as possible. Once the house is up to temperature (usually set by one or more room thermostats), the boiler would reduce output to maintain the required temperature. Without modulation, the boiler would be cutting in and out at full power as the house temperature falls and then rises. My understanding is that by running longer at a lower output, this is more efficient than short bursts at full power. But I could be wrong.

You've pretty much nailed it.

I record all the data coming out of my boiler and can see it starting up at 9-11kW initially, and then dropping down to 6-7kW once the system is up to temperature. As the house approaches the target temperature the boiler modulates down further to 3.5-4kW.

The main saving is that it doesn't have to fire up, run for a short period, stop, and then fire up again - That initial firing up is when the boiler is at its worst in terms of efficiency. Also puts extra wear & tear in internal components which could reduce the working life.

matelodave

Think of modulating like using the accelerator on your car, you put your foot down to get the car moving and up to cruising speed and then just gently adjusting the accelerator to maintain that speed. Its even better if you can avoid using the brakes (thermostats) and control the speed by gentle variation of the accelerator (weather compensation)

Compare that with the alternative of accelerating up to a speed and then letting the car slow by say 20mph and then putting your foot down again to get back up to speed and then letting the speed drop again and then accelerating again and doing it over and over again. That just like on and off control with a thermostat with a non modulating bolier where it has to restart at maximum output until it reaches cut-off temp and then keeps repeating.

QrizB

It's been less than a week but the weather has changed significantly since this thread was started and so has my household energy use.

On the 18th we used almost 55kWh of gas. Yesterday that had reduced to 25kWh. At today's price it would cost £3.32 and £1.51.

That's for a 1950s three-bed semi with less loft insulation than is recommended and only partial double glazing.