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

notanewuser

Herongull wrote: »

The logic is really simple, so can't understand why anyone even thinks of doing unscientific "tests".

Heat loss to outside = money (and energy) wasted. Anyone disagree with this?

Heat loss is minimised when:

1/ insulation is good. Anyone disagree with this?

2/ The difference between inside and outside temperatures is less. (Greater heat loss on cold nights. Greater heat loss if you heat the house to higher temperatures). Anyone disagree with this?

Therefore if you only heat the house when you need the heating on (ie when you are home and awake), you greatly reduce the heat loss.

Always have the heating off after you go to bed, because warm house and cold nights = very high heat loss. Keep the heating turned low in bedrooms when it is on, and get yourself a lovely John Lewis 13.5 tog down duvet:j

Both OH and I mostly work from home, so heating in all the time seems to be okay for us then. :beer:

And then at night we may be up seeing to our daughter, so keeping it warm is important then too.

knightrider_2

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.

One thing to bear in mind is how cold it feels. If my heating comes on at specific times of the day (currently 6am to 10am and 3pm to 11pm) my lovely wife will pushes the main thermostat up to 25c when it comes on and that is where it will stay for the rest of the evening because she carries that feeling of waking up to a cold house. If I leave the heating on constant at 18C overnight, the whole house feels warmer but the thermostat never goes up over 21C then. When we do this we also turn the upstairs radiators right down as the warmth from downstairs is always flowing up.

Some of our friends have electric underfloor heating and, while it is expensive to run, they rarely put the thermostat up beyond 18C. Their house is always on the comfortable side of cool. As opposed to ours where our feet are cool and the ceiling area is very warm with the middle bit reasonably comfortable. Low speed ceiling fans, incidentally, are a great way of distributing the warm air in winter as well as for cooling in the summer months. Not that I can remember the last summer we had.

hubb

I was bought up in a house with just a coal fire. No heating in my bedroom as a child. I survived.

oldskoo1

laptop80 wrote: »

Off-topic I know, but the amount of money saved by switching your broadband router off at night will be pretty negligible - probably less than a tenner a year.

However, there's a chance it may significantly decrease your internet speeds as line management by your phoneline provider will detect the drops (a switched off router looks the same to them as a lost connection for any other reason) and lower your line speeds to try to increase reliability.

I had it happen when I first go a wireless router and thought that I was being sensible by turning it off at the wall each night. They manually reset the line speed for me, but I understand it should go back up by itself over time. Also, routers are designed to be 'always on' and frequently switching the power on and off could potentially shorten their lifespan in some cases.

I should have said my broadband is with o2 on the LLU network so no line management. And your right, as i said these savings are tiny when compared to the electric heating, tumble driers etc.

jaemac

I live in social housing so I'm stuck with storage radiators, and no thermostat. I have to second guess what the weather will be like the next day when I set the input level. I rarely set it higher than number 4 (it goes up to ten) and this seems adequate for my needs., and I never put my heating on until I feel cold when adequately dressed. I keep my water on all the time as that is my one little luxury but it would be interesting to see if it makes a difference to have it on just at night. Again I'm stuck with a bath instead of a shower and it needs the whole tank to get a good soak. I think the most expensive pieces of equipment to run are my fridge and freezer, they seem to make up about 30% of my electricity. However I'm paying £40 a month for electricity, and that's for everything, which doesn't seem too bad. I'll have to see how much it goes up when the new price rises take effect. With 4 supermarkets within walking distance, plenty of little shops and a 24 hr Tesco maybe I don't really need the freezer :-)

Wintry

Q. Should I use a tumble dryer, or place washing on an airer with heating on?

A. An airer is better because tumble dryers use a lot of energy. Try timing it so you put your washing out on a clothes horse during thehours your heating comes on. Normally, that way you wouldn't use any more energy.

This is nonsense. The Energy Saving Trust can't change the laws of physics:
heat lost=heat gained
If people have their heating on, the implication is that it is cold outside, so they will have their windows mainly shut. The energy to dry clothes comes from the central heating, which has heated the air. The heat in the air in turn then dries the clothes by gradually changing the state of the water in the clothes from liquid water to water vapour by absorption of latent heat from the air by the water molecules, which is now ‘locked’ in the water vapour molecules. However, an increase in air humidity is undesirable, as it will result in condensation, so people then increase the amount of ventilation to get rid of it, by opening the windows, letting heat out. This involves the escape not only of some of the water vapour molecules carrying their latent heat (i.e. the heat actually used to dry the clothes) but also other warm air. The only way round this would be to have a ‘whole house ventilation system’ in which all windows are kept closed and ventilation is performed mechanically using a heat exchanger to capture the heat in the moist air being vented to the outside. Such systems are now available.

The energy used by a tumble drier has to be balanced against the energy lost by increasing the ventilation when drying clothes indoors. Obviously this depends on the outside air temperature, but the energy loss is likely to increase as the outside temperature decreases.The alternative is unacceptable levels of condensation, the long-term consequences of which also have energy implications, as well as other disadvantages. It is possible that when it is very cold outside, it is more energy efficient(without increasing condensation levels) to keep the windows closed and dry clothes with a tumble drier.

The response ‘that way you wouldn’t use more energy’ is incorrect. However, for most people it would be true to say that in the cost would be less because most people would have a combination of gas central heating and an electric tumble drier and gas is significantly cheaper than electricity.

laptop80

knightrider wrote: »

One thing to bear in mind is how cold it feels. If my heating comes on at specific times of the day (currently 6am to 10am and 3pm to 11pm) my lovely wife will pushes the main thermostat up to 25c when it comes on and that is where it will stay for the rest of the evening because she carries that feeling of waking up to a cold house. If I leave the heating on constant at 18C overnight, the whole house feels warmer but the thermostat never goes up over 21C then. When we do this we also turn the upstairs radiators right down as the warmth from downstairs is always flowing up.

Some of our friends have electric underfloor heating and, while it is expensive to run, they rarely put the thermostat up beyond 18C. Their house is always on the comfortable side of cool. As opposed to ours where our feet are cool and the ceiling area is very warm with the middle bit reasonably comfortable. Low speed ceiling fans, incidentally, are a great way of distributing the warm air in winter as well as for cooling in the summer months. Not that I can remember the last summer we had.

Perfectly sensible and partially explains why some people experience lower or similar bills when having the heating on all the time; if they're trying to make up for feeling cold the thermostat is cranked up far more than they'd normally feel they needed.

It's interested that people are often happy to have their house around 15C in the autumn, but as soon as the frost starts to bite they feel 25C is needed, as though it's suddenly necessary for temperatures to be the same as the height of summer.

Good point about the ceiling fans too - getting the heat where it's needed is half the battle.

macman

But all you need to do to keep your lovely wife happy is to set the timer to come on a bit earlier during cold weather, so that the temp is up to the required level at the same time as before (i.e. to counteract the greater heat loss). Putting the heating on all night at any temp may be more comfortable, but is vastly more costly.
A modern digital programmer with an optimiser function will do this automatically for you. and would pay for itself in a few weeks compared to turning the stat up and/or leaving the CH on all night when heat loss is at it's highest.

NSG666

I can't understand why the debate on this topic is continuing. The link on the opening post gives the answer. If you don't believe it and are happy with the bills that you get by leaving your heating on all the time then carry on doing what you are doing.

Mark_Beech

Those who are saying that this defies the laws of physics are simply not thinking this through.
The logic is that leaving the heating on 24/7 but controlled by a thermostat and turned down low overnight or when away from home CAN be as cheap as turning the heating on and off with a timer twice a day BECAUSE it takes an ENORMOUS amount of energy to reheat the fabric of a house that has been allowed to completely cool down. This will be less of an issue where the house is extremely well insulated and will be even more likely if its an old house with solid walls.
The other thing that people fail to recognise is the comfort factor. If heating only twice per day the fabric of the house will never get fully warm ..... you are essentially just reheating the air inside the house .... and it will never feel quite as cosy as when you heat 24/7.
It WILL almost certainly cost a little more to keep the heating on 24/7 - but not as much as many folk think. If you heat from say 7.00am - 9.00am then from 5.00pm - 11.00pm this will cost WAY more than a third as much as leaving the heating on 24/7.
Life's too short to be cold - and I know what I'm gonna continue to do!
It's a bit like the "where should I site the radiators" argument. The most EFFICIENT place to site them is on internal walls - but the way to be the most comfortable is to site them under a window. Guess where mine are!