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

orrery · 20 March 2013 at 9:36AM

dtse wrote: »

oh , and apparently we are only allowed to burn "smokeless" fuels so wood is out.

You should be able to use a proper wood-burning stove, as the technology re-burns the smoke, by feeding air in before it goes up the flue. We are in a smokeless area but the stove we have is approved for it.

John_Pierpoint · 20 March 2013 at 11:17AM

There are one or two office blocks in central London heated by wood, getting rid of the visible smoke is relatively easy, apparently the smell is more of a challenge.
Once upon a time the smell of burning (eg tobacco) was socially acceptable.

DonSwan · 16 April 2013 at 8:18PM

dtse wrote: »

Thanks John , it's an old build townhouse , on the outskirts of Edinburgh, we have solar panels & lots of insulation, new condenser boiler , but heating is still an issue due to high ceilings . The "magic box" was presented to us as a way of reducing gas bills in winter but I was sceptical due to what seemed to be improbably large savings quoted & high initial cost.

The Magic Heating Box is being sold by Green Home Energy, one director of which is Thomas Callaghan - former director of Simplee Solar, which was fined £40,000 plus £27,000 costs at Bournemouth Crown Court in 2006 for, "supplying and offering goods to which a false trade description applied".

Thomas Callaghan made an appearance on this forum in 2007 to defend his company's sales tactics, and to claim that the court case against him was rigged:
http://forums.moneysavingexpert.com/showthread.php?t=69974&page=3

orrery · 17 April 2013 at 9:47AM

John_Pierpoint wrote: »

There are one or two office blocks in central London heated by wood, getting rid of the visible smoke is relatively easy, apparently the smell is more of a challenge.
Once upon a time the smell of burning (eg tobacco) was socially acceptable.

I quite like the smell of wood burning - reminds me of rural French villages. The re-burn technology works well provided the stove is up to temperature - during the start-up there is still smoke and smell.

runrep · 1 May 2013 at 12:08AM

You guys make me laugh. :rotfl:Its a multi-faceted question and I keep reading the right answer to the wrong question.
''Is it cheaper...'' is one question. ''is it better/more comfortable.... '' is another and ''whats the most efficient'' is the right question. If money/saving is your only consideration, you should wrap yourself in £10 notes for insulation and live in a cave !!

It is patently obvious that burning energy, costs more than not burning it. So if you are going away it's better to leave it on 24hrs but turned right down to say 5 degs just to avoid freezing pipes (it rarely goes below 5degs inside, so you'll hardly burn any gas.). But if you're away for just an hour, its better left on at a reduced temp....say 15degs. Simply, the warmth you feel comes mostly from the heat your bricks and fabric have soaked up.....not immediately from the radiators. It takes more energy to heat you're bricks up from a v low temp (10degs) than from 15degs. So if you let it go too far down, even if you turn your heating on full blast, it takes ages before you 'feel' cosy again. The boiler also fires at a much higher rate for longer, so burns more gas before you feel cozy.

The best solution is to have a set back thermostat. This sets the heat at say 21degs while you're home/awake, and turns it down to 15degs there after. It obviously takes time to fall to 15degs from 21degs, so during that time the boiler is burning zero fuel. Then when it finally gets to <15 degs, it just lights at trickle rate to keep it topped up. At show time it only has to raise the house temp by 6degs to get back to a cozy 21degs again.

DragonQ · 1 May 2013 at 12:21AM

runrep wrote: »

You guys make me laugh. :rotfl:Its a multi-faceted question and I keep reading the right answer to the wrong question.
''Is it cheaper...'' is one question. ''is it more comfortable.... '' is another.
It is patently obvious that burning energy costs more than not burning it. So if you are going away its better to leave it on 24hrs but turned right down to say 5 degs just to avoid freezing pipes (it rarely goes below 5degs inside, so you'll hardly burn any gas.). But if youre away for just an hour, its better left on at a reduced temp....say 15degs. It takes more energy to heat you're bricks up from a v low temp (10degs) than from 15degs. Simply, the warmth you feel comes mostly from the bricks and fabric your home has soaked up.....not directly from the radiators. So if you let it go too far down, even if you turn your heating on full blast, it takes ages before it 'feels' cosy. The boiler also fires at a higher rate, so burns more gas for longer before you feel cozy.
The best solution is to have a set back thermostat. This sets the heat at say 21degs while youre home/awake, and turns it down to 15degs there after. It obviously takes time to fall to 15degs, so during that time the boiler is burning no fuel. Then when it finally gets to 15 degs, it just lights at trickle rate to keep it topped up. At show time it only has to raise the house temp by 6degs to get to get back to 21degs. This takes a lot less energy to make you feel cozy again.

I'm afraid the science and evidence disagrees with you. It is cheaper to turn off the heating if you're not using it, simple as that. Partly because using energy when you don't need it is obviously wasteful, partly because boilers are more efficient when on full power, partly because heating the house by a degree isn't any harder when it's cold than when it's hot.

Cosiness is completely different and you're right that having a house be warm already when you get home is nice. But it's still cheaper to have the heating turn off when you leave in the morning and turn back on half an hour before you get home than to leave it on all day. One can easily test this by checking gas usage in both scenarios.

orrery · 1 May 2013 at 9:37AM

runrep wrote: »

You guys make me laugh. :rotfl:
...
So if you are going away it's better to leave it on 24hrs but turned right down to say 5 degs just to avoid freezing pipes (it rarely goes below 5degs inside, so you'll hardly burn any gas.).

Glass houses and stones spring to mind, here.

If you do that you'll have frozen pipes and a flooded house.

Just because it is 5C by your thermostat doesn't mean that everywhere in the house is at 5C. Those pipes behind the kitchen cupboard or in the loft will need a higher temperature in the main living area to keep them above freezing if the temperature outside falls below zero for prolonged periods. Insulation around the pipes in the loft counts for nothing if the water isn't moving and the surrounding temperature is low for a very long time - it just makes things happen more slowly, the water in the pipe will still get down below zero eventually.

John_Pierpoint · 2 May 2013 at 12:48AM

Just leave the circulating pump running constantly, that is what I have always done.
With a solid fuel boiler in a detached bungalow, fortunately with south facing windows in a Southern coastal environment, I have not had much other choice.

DragonQ · 2 May 2013 at 9:03AM

Surely to prevent pipes freezing, the cheapest thing to do is have the heating come on for 30 minutes twice a day at normal temperatures. Hot water then flows everywhere for a brief time, preventing freezing.

orrery · 2 May 2013 at 10:45AM

John_Pierpoint wrote: »

Just leave the circulating pump running constantly...

Better than nothing, but it won't protect the cold water system in the loft. I left the house over the Xmas hols on a frost-stat set at about 7C a few years ago and it was only by having a fantastic neighbour who came in to check that I was saved a very expensive leak. He checked the cold taps and found that they didn't run, so turned the heating back on - he obviously just caught it in time.

I've made sure that Mum now has a set-back thermostat (sets back to 15C) and her heating is left on twice a day on the set-back when she is away.

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

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