Cheaper to leave heating on 24/7 or just when home?

samtheman1k

Anyone got a formula for calculating this?

Just been thinking over the last few weeks about my usage. I work 9-5 every weekday, so only have my heating on between 5am-7am and 5pm-1030pm. But, obviously, in those hours the heating (ASHP) is working flat out trying to bring the house back up to temperature. Presumably there is a breakpoint where it is cheaper to leave the heating on 24/7 and just top up as required rather than having it work full blast.

jenny2009

Try an experiment, read your meter then leave your heating on for 24/7 and also judge how comfortable your house is. Do this for a few days then read your meter and work out how much this is costing you.

Repeat the experiment except using your heating on timed.

What is cheaper? What is more comfortable?

Report back and let us know.

Jen.

Cardew

From the Energy Saving Trust

Question

Is it more economical to leave my heating on 24hrs in the winter?

Answer

No. It is a common misconception that it is cheaper to leave your hot water and heating on all the time. Boilers use more power initially to heat water from cold, however the cost of this is greatly exceeded by the cost of keeping the boiler running all of the time.

The best solution is to programme your heating system so that it comes on when you need it most (possibly early morning and in the evening), and goes off when you don't need it (when you are out of the house or asleep). There are a range of controls that can be used and your heating engineer will be able to provide you with the most appropriate solution.

Depending on your circumstances it may be necessary to keep the heating on all day during winter but it will cost more than if you turn the heating off when you don't need it.

That is supported by the laws of physics - the law of thermodynamics.

Doesn't matter how hard your ASHP has to work. The issue is heat loss.

The warmer your house, the greater the heat loss.

So keeping your house 24/7 at, say, 20C will mean that you will lose more heat than allowing to fall to say 15C while you are at work.

Please, please, don't let anyone start talking about which is more comfortable, that isn't the exam question - samtheman1k asked which is cheaper!

jenny2009

Please, please, don't let anyone start talking about which is more comfortable

why, is that not what it is all about? cost versus comfort. I get up frequently during the night and I prefer the kitchen to be warm when I go there to make a hot drink at 3 in the morning, and don't mention flasks I hate them, that is where the comfort comes in. I pay extra for my comfort.

I know it costs more to keep the house warm during the night, I did the same experiment I suggested years ago and it cost less for gas with the heating off during the night than leaving it on, but there is so much conflicting advice that is why I suggested experimenting so that the OP can decide for himself.

As you are aware Cardew, if it was that simple, there would be no postings asking if it was cheaper to put something on intermittantly than leave it on all the time because if it were, every person who asks the question well I'll leave it to you what we call them.

Jen

Cardew

jenny2009 wrote: »

why, is that not what it is all about? cost versus comfort.

I pay extra for my comfort.

No that isn't what it is all about, that wasn't the question asked by the OP he didn't mention comfort; he asked:

Cheaper to leave heating on 24/7 or just when home?
Anyone got a formula for calculating this?

Just been thinking over the last few weeks about my usage. I work 9-5 every weekday, so only have my heating on between 5am-7am and 5pm-1030pm. But, obviously, in those hours the heating (ASHP) is working flat out trying to bring the house back up to temperature. Presumably there is a breakpoint where it is cheaper to leave the heating on 24/7 and just top up as required rather than having it work full blast.

Lots of people believe it actualy is cheaper to have the heating on constantly as the boiler(or ASHP in this case) doesn't have to work as hard.

That is why the Energy Saving Trust state

No. It is a common misconception that it is cheaper to leave your hot water and heating on all the time

You, and I, are prepared to pay extra to have heating on for just as long and just as warm as we want. However we don't labour under the 'common misconception' that it is actually cheaper to have the heating on 24/7.

TheSaint_2

It will more than likely be cheaper to run it the few hours a day you are in.
BUT
If you get your house properly insulated, and do all you can in that area you will find as I did that you can leave your heating on 24/7 and the heating will only fire a couple of times a day anyway because your house doesn't lose nearly as much heat. So your comfort level will increase and your bill will probably go down compared to what you are paying now.