Since starting to reduce our fuel use for heating and hot water, this little Galileo thermometer has stood on our mantelpiece giving us a visual indication of the room temperature.
We have gas central heating and up until a few years ago I used to set the timer clock at the start of the winter and leave it on the same setting until spring. The heating would switch on for a couple of hours in the morning as we were getting up and then switch on again mid afternoon until bedtime. I think back then the thermostat was set for around 18-20C (64 -68F). Not any more!
When I started thinking about how much heating we actually need, I realised that the temperature of the house varies from day to day depending on the amount of sunlight, the number of people at home, the amount of cooking etc. The temperature we require also varies depending on what we are doing, the temperature needs to be higher if we are sitting reading or watching television than if we are cleaning, cooking or moving around.
So now we have reduced the thermostat setting to 15 C (59 F) and the heating comes on automatically for 45 minutes in the morning just before we get up and for three hours in the evening from 6-9pm. If the house cools too much outside of these times we push the "extra hour" button for some additional heating.
We use the Galileo thermometer as a quick guide to the temperature of the living room. Ours has four glass bulbs, calibrated at 16, 20, 24 and 28 C. If all the bulbs are at the top of the tube then the temperature is below 16 C (61 F) and if we are cold we add an hours heating. If the red bulb has dropped to the bottom of the tube (as in the first photo) then the room temperature is above 16 C and the rule is that if you are cold at this temperature then you should be wearing more clothes!
After several years of keeping to these temperatures we now all have a good supply of warm clothes (lots of layers) and find we are quite comfortable running the heating a lot less than we used to.
I have recently completed one of those carbon footprint calculators. I put in the figures for our 2007 gas usage and was pleased to find that per person we came out at well under a third of the average UK carbon dioxide emissions for heating and for electricity. Using this little thermometer to gauge whether the house really is cold or whether we should wear an extra sweater must have saved us a considerable amount of money and fuel - its certainly paid for itself.