We’ve had a lot of questions over the years about turning down your heat, both daily and when you go away.

Does turning the thermostat down save money? The short answer is yes.   The flow of heat from the house to the outside is proportional to difference between the temperature inside the house and the temperature of the air outside. if you allow the house to cool down,  that difference is made smaller and therefore the heat flow to the outside is less.

This means that by reducing the temperature

Digital setback thermostat

inside your house less energy  is required to maintain that cooler inside temperature.

Some people argue that the energy you use bringing it up to temperature negates the savings, but that energy use is  actually canceled out by the fact that when you do turn it down, it doesn’t run for that period of  time that the house is cooling off.

The average home will save about 2 percent for each degree you turn the temperature down for 8 hours. So it is worth turning it down for the day, or overnight. It does save money. You may not save much turning it down for a few hours. So if you turn it down from 70F to 65F overnight or during the day when no one is home, you should save around 10%!

There is one really large problem with turning the heat down when you go away, and it’s the reason that we advise our clients to leave the heat set at whatever their NORMAL turned down temperature is.

Over my 35 years of doing plumbing and heating, I have seen  dozens of freeze ups that have occurred in houses where the heat is NOT broken.

Here is the typical scenario: The homeowner is going away for a month to Florida. Lucky them!  So off they go, usually early on a cold morning, heading to the Expressway to go to Logan airport. The last thing they do as they leave the house in January is to turn the thermostat down to 55F. After all, no one is home so there is no need to keep the house any warmer. Normally they turn it down to 62F when they go to bed and it’s never a problem,  so why not turn it lower? Let’s see, another 7degrees, for 30 days, why they should save a good 14% off their energy bill, which is $350 a month, so that’s a savings of  $49.00. Here is the problem: when they left, the house was up to 70F as they got ready, then when they left they turned it down to 55F. They’ve done all the right things, fixed and caulked windows and doors and insulated where they could, so the house looses hear pretty slowly.  That 15 degree cooling off period takes most of the day, so the heat doesn’t come on until the afternoon. That long off period means that any piping in the house that isn’t far away from an outside wall has a chance to freeze and burst.

Burst pipe

This could be (and commonly is) water piping above the kitchen that has a breeze blowing on it down the joist bay. Normally there is enough heat around the house to prevent this from being a problem, but this day the heat is off all day.  Then the heat comes on, the pipe thaws, and there is a major disaster, that could go on for days! I’m pretty sure that this will cost a lot more than $40.00 to deal with.

My recommendation, to all my clients, is to leave the heat on the lowest normal temperature that you have set on your thermostat. I myself leave my heat on 62F, which is what is it set on overnight and most of the day, and I have a friend in my neighborhood check my house once a day. There are also various types of alarms that could be set to notify someone  when there is a problem, from simple thermostatically controlled light switching, to automated dialers that could be installed.

So turn your heat down, but be careful when you go away.