Naked Science Forum
General Science => Question of the Week => Topic started by: katieHaylor on 09/12/2019 09:33:51
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Tim says:
The experts at the Energy Saving Trust and British Gas say it's cheaper to heat your home only when you need it. But my heating control panel says that it uses less energy to keep a background temperature when the room is unoccupied, than it does to allow the dwelling to chill too much. I'm confused! Which advice is correct?
Can you help Tim out?
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Heat loss depends on source temperature, so if you let the room cool down in your absence, you won't be using or losing any heat. Frost protection is still essential but the trick is to set the lowest protection temperature (obviously above 0 deg C) that you can tolerate on your return. However some refrigerators and freezers won't work in an ambient below 15 deg C, so beware - if the fridge stops cooling, your food will slowly heat up to room temperature, way above the safe storage level for food. Consequently many thermostats set 17 deg C as "frost protection".
I find 17 - 18 deg C a perfectly acceptable ambient anyway, so I set thermostats at a constant 17 C for the kitchen (and also the room with musical instruments - pianos really don't like low temperatures) but 5 C for unoccupied noncritical areas.
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What's the cheapest way to heat your home?
Move to the tropics.
...Then the next question will be: "What's the cheapest way to cool your home?"
Clearly, thermal insulation has to be a big part of the answer!
...and living in a temperate climate helps, too.
Having carbon-neutral energy helps, like hydropower in Norway, or solar power in more sunny areas.
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I suppose if there is a temperature difference between rooms the hot air is given the impetus to move out so you end up with a very cold room that has hot air rush from it and is difficult to heat, plus extra heat into the rooms you are not in, where as if all rooms are moderate there is less high intensity heating just for one room ?
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Setting fire to election leaflets may help with low cost heating.
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Or just leave the radio tuned to any politics program and fill the room with hot air. Next week, try economics, philosophy or religion. Or even one of those interminable sports programs that speculates on what might happen if United get a score draw or City lose by five wickets. Does nobody broadcast actual facts any more?
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This is too broad a question. But it's something of interest to me.
I think heat exchangers are key. But you need air tight houses for this.
We tried a radiator in the bathroom, and without pretty much constant ventilation, we get a build up of mold. With heat it spreads.
So we just don't heat it anymore and keep the window open always. Luckily the south of England isn't freezing that much any more.
Ideally though we'd have a heat exchanger, and warm humid air would be expelled and used to warm fresh incoming air.
Draughts provide a trickle of fresh air, but are also responsible for heat loss. So if you can remove them with the above system you'd be onto a winner.
Houses that are well insulated, air tight, and have large windows don't need much heating at all if you engage in a system as above. Humans give off heat. Appliances run somewhat hot etc.
But this is not much use to those with old housing stock.
We do tend to gravitate towards one small room in the winter. Our lounge is below the bedroom. And we can turn off all the other radiators. So only need to heat those two rooms. A few cold other rooms isn't the biggest hardship.
We've looked at retro-fitting our old victorian house. And it's pretty pointless. I wish they would raise the majority of the British housing stock to the ground, and build/replace with proper energy efficiency in mind. Taking into account the whole lifecycle. I'm sure they could recycle existing on-site materials from the spoils.