No.

The heat loss depends upon the difference in temperature between inside & outside. So allowing the internal temperature to fall reduces the heat losses.

If you live in a lightweight/timber frame house or one with poor insulation & you are heating with natural gas then better to just heat the house when you're in & need the heat.

If you live in a heavyweight/masonry house with high levels of insulation that only loses 1 or 2 degrees per day without heating then the question becomes what is the most efficient way of getting the heat into the house during a 24 hour period. If you're using natural gas then do whatever is most comfortable. If you're using a ground source heat pump then it's worth looking at whether you could use it purely during the low rate Economy 7 period & make use of solar gain during the day.

David

Also, to add to DJH's comments, when the boiler is on a certain amount of heat goes to heating up the boiler itself (the metalwork) and some will go out the flu, this does not happen when the boiler is off. If the boiler is inside (as most are) the heat in the boiler goes into the house anyway with only the flu heat lost. If the flu temperature is the same as the ambient temperature then there is no problem with heat loss (but it will be higher). Remember there is a difference between Heat and Temperature.

<blockquote><cite>Posted By: StuartB</cite>Is it more efficient to leave your gas central heating on constantly at say 19c which allows the house to heat up and then tick over rather than letting it go cold overnight then heat up in the morning cool during the day then give it a further boost in the evening?

Any evidence to support this?</blockquote>

It is very simple --- the colder the house the less energy it will use. In terms of efficiency there are many aspects, I am unconvinced that you are meaning to talk about efficiency rather I am thinking that you are trying to talk about cost effectiveness or the best way to pay for fuel for the maximum benefit. Unfortunately the less fuel you use the less it will cost and the colder the house will be. You get what you pay for

When I had a heating system I ran it on a chronostat, 15.5C overnight, 18C in the morning for getting up, 16 during the day, 19 when the kids came home and 21 when we all sat down, 22C all day Sunday etc. This is not the cheapest or most efficient way to run it but it was comfortable, my heating only came on in the night twice in 20 years under that regieme.

Suppose you have a solid thermally heavy wall like StuartB has, and you heat it for 12 hours then not for 12 hours. Is it possible to set up a wave of heat travelling through the wall? So, at the end of 12 hours of heating, the inside of the wall reaches a maximum. The heat travels through the wall to the outside. The inside of the wall cools to a minimum over the next 12 hours, by which time the outside of the wall is at a maximum and losing heat to the atmosphere.

If these time constants line up, I would imagine that you would have to overheat the air in the house at the start of the heating period to allow for the large radiant losses you would feel to the now cold inner face of the wall. In this case, might it be more economical to keep the temperature relatively constant?

Please bear in mind that I have no training in this sort of thing, so could be talking complete rubbish...
Brian.

Tony, have done as much as possible but we are renting until we find a plot to build so reluctant to spend too much. Landlord will not cough up for 'extra' insulation.

Mike, boiler was new in June so that's not an issue, it's the radiators that are too small or in the case of the kitchen non existent (may have to fork out to fit one).

Do you think this method would work.

Run it on short bursts and take the gas meter reading for a 24 hour period, then put it on constant for a week to allow build up of heat in the thermal mass and then take a 24 hour reading.

If you can work out the thermal response time for your building then you should be able to calculate the ideal 'burn time' and temperature.
Start by heating the building up, then when it is dark get two thermometers, one inside and one outside, and every ten minutes not the temperature readings. Do this for a couple of hours. Plot Temperature difference against time and you should have an exponential decay curve, that's one that shows a large drop initially and then starts to flatten out as the temperature difference tends toward zero. Then turn the heating on and see how long it takes to get up to the temperature you want, say 20C. To make it really interesting take meter readings over this period. Again plot against time and you should have a exponential growth curve (one that starts quickly and ends slowly). You will notice that for any given temperature difference there is a difference in the rate of change between heating and cooling (cooling being quicker). So to find the ideal 'burn time' find the time difference at 1C above and 1C below the temperature you want and calculate the time it takes to raise the temperance to the upper bound (heating) and then how long to reach the lower bound (cooling). You will now know how long to have the boiler on for and how long to have it off for to hold the temperature around what you want.
Simple eh.

Different outside temperatures will change the slope of the line, but not by much as you have thick walls and the thermal response time will be pretty slow.

Probably Tony