Energy myth-busting: Is it cheaper to have heating on all day?

Cardew

You simply cannot measure consumption over a period of 20 minutes and the extrapolate the result to cover a longer period of time.

Even with an old non-modulating boiler, it will stop firing when the water has reached the set temperature.

In the same way you cannot measure the MPG of your car over 1 mile at 30mph or at 150mph and conclude either figure is the average fuel consumption of your car.

Heinzbean

Why not i use the system caveman style  switch it ON   switch it OFF..

Its on its using energy ...when its off its not using energy.  20 minute blasts....I am the thermostat..

these 20 minutes must use an amount of gas which is measurable..(if you have an accurate way of measuring). The same amount of gas every time i give it a 20 minute blast.

This way of running the system is cheapest for me..as i have two years worth of usage which proves this.

I do believe a smart system that can control each radiator valve , turn off certain rads and tweak the system would be MORE efficient............. but i have not got round to sorting that yet...

victor2

Heinzbean said:

Why not i use the system caveman style  switch it ON   switch it OFF..

Its on its using energy ...when its off its not using energy.  20 minute blasts....I am the thermostat..

these 20 minutes must use an amount of gas which is measurable..(if you have an accurate way of measuring). The same amount of gas every time i give it a 20 minute blast.

This way of running the system is cheapest for me..as i have two years worth of usage which proves this.

I do believe a smart system that can control each radiator valve , turn off certain rads and tweak the system would be MORE efficient............. but i have not got round to sorting that yet...

For those 20 minutes is the boiler actually burning gas throughout that time? Almost certainly not. It just gets the water up to a set temperature and maintains it there as require.

Your caveman system is not that simple to equate to running costs. What is the temperature of the house and water in the radiators at the start and end of the 20 minutes? How many minutes of the 20 was the boiler actually heating the water?

Do you have lots of 20 minute runs at different house temperatures and at different stages in the day, to average them out to get an idea of the running cost? Even that will not allow you to say "I'm just going to run the boiler for 20 minutes - it will cost me £x".

Heinzbean

No   today  i switched it on at 3-00   off at 3-20.......boiler was on for 20 minutes...........

house stayed warm 

turned it on at 8-30 off at 8.50    house was to hot.........So today 40 minutes worth of heatiing.....

Heinzbean

using it caveman styley 

09-01-20  i used   43 ft3. month

this next year i was using it  setting the thermostat to 18"

07-01-21  i used    60 ft3 month  so much higher usage....

This year back to caveman styley  will record the usage....

Heinzbean

Cardew said:

In the same way you cannot measure the MPG of your car over 1 mile at 30mph or at 150mph and conclude either figure is the average fuel consumption of your car.

but you could test a motorbikes mpg by putting 1/2 a litre of fuel and times the mpg x 9

JohnSwift10

I have my heating on all day from 07:45 to 23:30 with a thermostat setting of 21 deg C and it is currently using 33kWh a day.

This gives an average of approx  2.1 kW  of gas per hour.

Total including hot water and cooking is 45 kWh a day.

This is a 3 bed semi with double glazed windows and 260 mm loft insulation and a combi boiler.

How much are other people using when they have their heating on for a couple of hours in the morning and 4 or 5 hours at night in a similar 3 bed semi?

Spies

You must have a very well insulated house. 

shinytop

I have my heating on 24 hrs a day using weather compensation (flow temperature based on outside temperature) and the whole house has been about 21-22C .  Over the last  6 days I've consumed 75kWh of electricity in total on heating 

This gives an average of approx  520W  per hour consumed.  

This is a 1990 4 bed bungalow with double glazed windows, 270 mm loft insulation and an ASHP. 

richardc1983

An interesting video that explains really well and in easy terms why it is cheaper for some people to leave the heating on all day low and slow than timed periods in high temp bursts of heat. 

https://youtu.be/kGs_biFA87Q