This post is going to be a bit of deflection, because the answer to the question is a simple one: Yes, your furnace works harder on colder days. It doesn’t work differently when it’s colder—the same principles of how the furnace heats and distributes air are at work. What makes the furnace work harder in cold weather is that it must run for longer to raise the interior temperature of your house to the target you need for comfort.
Now here’s where we deflect, because talking about your furnace working longer during cold weather needs some examination. The, ahem, cold fact we’re looking at is that you are probably making your furnace work harder than necessary on those cold days. This leads to higher energy bills, but it can also lead to a furnace that fails abruptly in the middle of one of the coldest days of the year. Knowing more about your furnace running on cold days can help you avoid emergency heating repair in Cincinnati, OH.
Don’t try to heat your home “faster” with thermostat settings
This is a critical piece of information we wish all homeowners understood. The lower the temperature in the house, the longer the furnace must continue to run to raise it to the setting on the thermostat. Unfortunately, this can lead to a bit of fallacious logic from the person adjusting the thermostat: “Why not raise the thermostat setting higher to get the furnace to heat the home up faster?”
The furnace and the thermostat don’t work that way. The thermostat is a switch: it turns the furnace on and keeps it running until it senses the house temperature has reached the target setting. It then shuts the furnace off. Raising the thermostat setting doesn’t mean the furnace “throttles” up to produce heat faster. It only means the furnace will run for longer. This puts more strain on the furnace, makes it more expensive to run, and will end up giving you a house that’s too hot.
We recommend keeping the thermostat at 68°F during the day time on cold days: this is an energy-saving setting, and should be comfortable for most people wearing warm clothing.
Heat loss on cold days is an important factor
Some basic physics of heating: the bigger the temperature difference between the outdoors and the indoors, the faster heat escapes to the outdoors. On extremely cold days, your furnace has to deal with a more rapid loss of heat, another reason it must run longer. The better insulated the house, the slower the heat loss.
But there’s another way you can help slow down heat loss, and that’s to keep the thermostat temperature setting lower. The 68°F setting we mentioned above is ideal for reducing the speed of heat loss in the house. So not only will your furnace have to work less in order to meet the temperature setting, it will work less because it won’t have to replace as much lost heat.
We hope this short exploration of a furnace working on a cold day will help you enjoy a winter with few heating problems and lower bills. When you do need furnace repairs, we have 24-hour emergency service.