This one is very simple:
Turn down the thermostat at night!
We find it surprising that
so many people (physicists included) find this a problem, so let's try to explain
it in as straightforward a way as possible.
Here is the key idea. When
you're "heating a house", all you are really doing, in the long run, is replacing
the energy that is being lost to the outside through the walls. So the simplest
way of finding out how much energy you have to supply is to find out how much
energy is being lost through the walls. And the rate at which energy is lost
to the outside depends, of course, on the walls. How big is the house? What
are the walls made of? How thick are the walls? Are there open windows? And
so on. Those are not our concern here. The rate at which energy is lost also
depends on the temperature difference between indoors and outdoors, and the
outdoor temperature is not something we can change. The thing you can control
is the indoor temperature, with
your hand on the thermostat. Lowering the indoor temperature means a smaller
temperature difference between indooors and outdoors, and thus less energy lost
to the outside, which in turn means less energy that you have to replace. That's
all there is to it.
It's true that the heating system has to work extra hard to warm up the house in the morning, but that's balanced by the fact that in the first hours after you turn the thermostat down, you don't have to put energy in at all. And all night long, while the house is at 60, say, instead of 70, you're losing less to the outside and so there is less energy that your heating system has to make up for.
When we put our minds to
it, we can think of a few conceivable effects that might modify one's personal
decision about turning the thermostat down. If you have to get up in the middle
of the night and you really, really hate a chilly house, then (for you) it might
be worth the extra cost to keep the house warm all night. Or, with electric
heat, it might be that you have to pay a higher rate in the early morning -
when you're warming the house back up - than you do in the middle of the night.
But those are just quibbles. The basic point remains that in order to decrease the total amount of energy your heating system has to supply, TURN DOWN THE THERMOSTAT AT NIGHT!
to bus placard for the thermostat
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