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

Former_MSE_Guy

This is the discussion for the following MSE guide.


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

Herongull

This all just seems commonsense. I'm surprised the article was necessary.

notanewuser

My FIL worked for British Gas as a heating engineer for 42 years and swears blind that it should just be left switched on with a thermostat at the temperature you want. He's a (very) tight northerner so I'd be surprised if this weren't the most cost effective option.

I've always hated my OH turning the heating way down/off when we go away for weekends, only to come back to a freezing cold house and no hot water. Now that we have a toddler there's no way I'm letting him do that, so ours is on with a thermostat set to 20. Lovely.

WestonDave

Ye canna change the laws of physics!

If you want to change water from its liquid state to its gas state in order to get it out of the washing, you will have to use energy. Whether you do that by using a dryer or by making the heating work harder, you will use the same amount of energy. The heating might be cheaper per kWh but its less directed so you may end up heating the whole house for longer rather than a small drum. Vented dryers are wasteful of energy as the heat all goes outside whereas at least with a condensor dryer the heat stays in the house and offsets that from a well controlled heating system.

Which brings me to the first comment - there is such a thing (widely available) as a programmable thermostat which combines timer and stat - which is better than either option listed. The problem with timers is that if you are going to run the heating flat out on a timer you end up heating the house too hot in order that as it cools when the heating is off, it still stays warm enough. A programmable stat still allows it to be off when you are out (or cooler at night etc) but avoids the wasteful overheating.

Cardew

1. Well firstly please make this thread a sticky as the 'Cheaper all day v timed' question comes up a dozen times each year.

The normal variation of that question is:

'Which is cheaper - on 24/7 at, say 15C or in timed bursts to 20C'

A question nobody can answer!

2. The EST have a fixation about standby consumption. The manufacturers got to grip with that problem many years ago and standby consumption for, say, TVs is tiny - fractions of a watt. You can leave a modern(up to 10 years old) TV on standby 24/7 for a year and the cost is pence. Even the worst of my TV's - an old 32" CRT has a standby consumption of 0.6 watts. so left on 24/7 it will cost 63p a year with electricity at 12p/kWh.

Obviously any saving by switching off at wall is welcome, but the emphasis on standby consumption leads many people to think it is the major cause of high electricity bills - and it aint! We get countless posts complaining about high electricity bills and nearly all are at pains to point out that they switch off TV at wall.

3. This is misleading IMO:

Should I turn individual radiators down at the valve or will it only make a difference if controlled via the main thermostat?


a. There's little difference. By turning your radiators down or
off using thermostatic radiator valves on the side of them, or by reducing your
room temperature via a thermostat, you decrease the amount of heat your heating
system has to generate.





Your room thermostat only switches your heating off when the set temperature
has been achieved, so turning your thermostatic radiator valves down will mean
your radiators will not get as hot and will gently heat your home to the set
temperature.


If you have them on high, your radiators will emit lot of heat until the set
temperature is met.

That might apply to the TRVs and thermostat in the same room. However the purpose of TRVs is also to control the warmth of other rooms. Most people would want their bedrooms set to a low temperature during the day which you can achieve with a TRV. e.g a reception room set to 21C and bedrooms to 16C

4. The recommendation to use an airer instead of a tumble dryer is questionable in modern houses that are almost hermetically sealed!! The problems of condensation and mould can be serious.

Cardew

notanewuser wrote: »

My FIL worked for British Gas as a heating engineer for 42 years and swears blind that it should just be left switched on with a thermostat at the temperature you want. He's a (very) tight northerner so I'd be surprised if this weren't the most cost effective option.

I've always hated my OH turning the heating way down/off when we go away for weekends, only to come back to a freezing cold house and no hot water. Now that we have a toddler there's no way I'm letting him do that, so ours is on with a thermostat set to 20. Lovely.

Well your FIL is completely wrong!

You say that you leave heating set at 20 when away for the weekend.

If you were away for two years, would you leave it set to 20C?
How about a month? A week? At what point do you feel the laws of physics don't apply?

notanewuser

Cardew wrote: »

Well your FIL is completely wrong!

You say that you leave heating set at 20 when away for the weekend.

If you were away for two years, would you leave it set to 20C?
How about a month? A week? At what point do you feel the laws of physics don't apply?

No, that's not what I said (is it?).

What I meant was its set to 20 when we're here, and then left on at about 15-16 when away (so that we don't come back to a 5 degree house that takes days to warm up). If we were away for a fortnight or more in winter we'd leave it set to 10-12 degrees to stop pipes freezing. The heating is off in summer.

sheffield_lad

Cardew wrote: »

Well your FIL is completely wrong!
You say that you leave heating set at 20 when away for the weekend.

If you were away for two years, would you leave it set to 20C?
How about a month? A week? At what point do you feel the laws of physics don't apply?

It really does depend on the insulation and the type of stat. I have a digital room stat and house is insulated well. I was in all day Sunday and the heating never fired up all day the room stat was set to 20. If I go away in the winter period I normally set the stat for around 16 degrees.

I never use a timer as I can't see the point of being cold and waiting for the heating to fire up at a certain time. I use the room stat so during the day 20 deg, sat down at night in my boxers lol 22deg, overnight 20 (although I have only heard it fire up a few times over the colder nights a week or so ago).

My wife works from home so house is never empty boiler is 11yrs old but running it like this never gives me a large bill £56 per month over the year which I consider not bad at all.

ariba10

Physics is not a strong subject on M S E ?

notanewuser

ariba10 wrote: »

Physics is not a strong subject on M S E ?

Come on then, Prof Brian Cox.

Cardew

notanewuser wrote: »

No, that's not what I said (is it?).

What I meant was its set to 20 when we're here, and then left on at about 15-16 when away (so that we don't come back to a 5 degree house that takes days to warm up). If we were away for a fortnight or more in winter we'd leave it set to 10-12 degrees to stop pipes freezing. The heating is off in summer.

That is exactly what you said:

I've always hated my OH turning the heating way down/off when we go away for weekends, only to come back to a freezing cold house and no hot water. Now that we have a toddler there's no way I'm letting him do that, so ours is on with a thermostat set to 20. Lovely.

Note - no mention of '15/16'