Is it more economical to leave heating on?

teabelly

In the very cold weather I tend to leave the heating on constant as by morning the temp has dropped so far the boiler can't get the house up to reasonable temperature within the two or so hours. Also I can turn the boiler right down and leave it on constant rather than turning it on a higher setting for a few hours a day.

I think it partly depends on the rate at which the heating can up the temperature and the rate at which the house cools down in the absence of heating. I can't see the point in having timed heating that means the house is only warm by the time you want to go to bed! I used to do that and the house was freezing all the time even with the boiler on quite high. I flicked it over to constant, the house was warm all the time, the boiler was on a lower setting, the radiators were turned down and the gas bills weren't noticeably larger than the previous year.

Some of the heat will go into the fabric of the building and that seems to make the internal temperature more stable if you leave the heating on constant. This seems to allow you to feel warmer with the heating on a lower setting so I think from that point of view it may be cheaper as you need less heat to maintain the required temperature on a daily basis.

Would like to see some scientific proof tried in different house types with different boilers and heating types under controlled conditions to test these theories though.

oldskoo1

I know there are scientific explanations to all of this etc but have two very simple numbers

oct-jan 07
20dC - 1hr morning, 5hrs evening
avg. mean temp 4.4dC in december
491 units of gas

oct-jan 08
18dC 24/7 (constant)
avg. mean temp 3.1dC in december (Significantly colder than previous year).
528 units of gas

So same house, same people, same rads, same boiler, same hot water tank. Hardly any difference in gas usage which you could put down to the much colder winter compared to last year (based on met office figures).

Upshot is a house that is constantly warm.


But i will always advise, always read the meter when you try this, if your house isn't too good on insulation or draft proofing if might show up bigger differences.

Cardew

oldskoo1 wrote: »

I know there are scientific explanations to all of this etc but have two very simple numbers

oct-jan 07
20dC - 1hr morning, 5hrs evening
avg. mean temp 4.4dC in december
491 units of gas

oct-jan 08
18dC 24/7 (constant)
avg. mean temp 3.1dC in december (Significantly colder than previous year).
528 units of gas

So same house, same people, same rads, same boiler, same hot water tank. Hardly any difference in gas usage which you could put down to the much colder winter compared to last year (based on met office figures).

Upshot is a house that is constantly warm.


But i will always advise, always read the meter when you try this, if your house isn't too good on insulation or draft proofing if might show up bigger differences.

Those statistics are readily believable; however there is a big difference between 18C and 20C. That is what I said in the first post I made.

Prevailing wisdom is that it adds about 10% to your heating bill for each 1C.



The dispute is about this statement:

Without question the gas consumption needed to keep my system at a constant temperature is far less than that needed to bring it back up each morning and night.

Which is quite patently incorrect!

oldskoo1

ok

agreed big difference between 18 and 20.


The difference for us being, 18 constant keeps all the airspace, walls, furniture everything heated to some degree.

When it was on timed we had to turn it up to 20 for it to feel tollerable. Even though it was set to come on 1hour before we woke up or got in, it was always FREEZING. I remember shivering and had to put on loads of clothes instantly.

Now its constantly comfortable and warm.


Even if people work all day, i would install a £30 programmable thermostat so you can have to set to 16/17 all night and all day then flick up to 18 1 hour before you get back from work until you go to bed.
Normally in a morning your not around for long enough to benefit from 18.

basmic

I doubt most people could tell the difference between heating on left overnight, and heating being set to come on an hour before they wake up.

Personally, if it feels cold in the morning, I just turn the heating on.

loulou41

I put mine on all day at 18oc or more if cold but not more than 21oc in very cold weather. I do not think I could sleep with the heater on all night, I will be too hot. If it s cold, then I leave the heater on at night.

sensibly_insane

There is no universal answer to this problem. There are a number of a variables such as insulation quality of the house, size of the house, outside temperature, pattern of usage etc. It is really very difficult to formulate to get a certain answer.Hit and trial is the best solution in my opion for any given house. It turned out to be more expensive for us to switch on and off the heating for some time slots. Now we keep the house at 18 when we are at home and at 15-16 when we are out or are sleeping.

Important is to keep an eye on the usage of gas; depending on the gas tarriff one can work out how much this tecniuqe costs or one can call the gas supplier and ask them to calculate it for you.

Hintza

Much better to sleep in cold bedroom overnight with heating coming on to warm you in the morning.

Interestingly our neighbours have just completed a new house with underfloor heating downstairs and NO heating upstairs at all.

psychoceramicist

Try this.
Unless your insulation is 100% efficient, what you are paying your heating bills for is to heat the environment not your house. Otherwise you could heat up your house to the desired temperature once and then turn off your heating for ever. You have to keep heating and keep paying because heat is escaping all the time.

Whatever the insulation, the greater the difference between the temperature inside your house and outside, the faster your heat loss and the greater your costs. So the less time you have the house hotter than outside the less your costs. So use a timer to switch off the heating when you don't need it.

Cardew

psychoceramicist wrote: »

Try this.
Unless your insulation is 100% efficient, what you are paying your heating bills for is to heat the environment not your house. Otherwise you could heat up your house to the desired temperature once and then turn off your heating for ever. You have to keep heating and keep paying because heat is escaping all the time.

Whatever the insulation, the greater the difference between the temperature inside your house and outside, the faster your heat loss and the greater your costs. So the less time you have the house hotter than outside the less your costs. So use a timer to switch off the heating when you don't need it.

You can say that until you are blue in the face( as several of us do) but every few months you will get someone(as above) - who will tell you that is just theoretical rubbish and they have 'proved' that constant heat 24/7 is cheaper than timed. e.g.

With systems and homes constantly changing these days you have to be open minded to other possibilities!! My underfloor heating works better this way I've been told, by people who have spent a lot of money on R&D. ----

Anyway, what I can tell you all is that for ME, it IS more efficient and no amount of theoretical debating can suggest otherwise or disprove fact.

Sadly posts like those come up all the time - the sad part being that people believe them(or want to believe them)