You know the day is coming, don't you? That bone chilling, brain freezing, face numbing cold day that makes us wish we could hibernate until spring. 

If you're one of the unfortunate souls who has to park your car outdoors, you may have to chisel your way into your car and pray it starts up right away. And often times, it takes a little extra time and effort to get that motor running.

So, if our cars have a hard time running when it's subzero temperatures outside, does our furnace have to work harder when it's colder, too?

Colder Days are Easier on Your Furnace

Contrary to what many might realize, a deep cold snap can be better for a furnace than those 30- and 40-degree days. Why? It's better for furnaces to operate in long, sustained runs. Just like car engines, furnace motors don't like to start and stop. Have you noticed how much better your gas mileage is when you're on the highway versus driving on city streets? That's because your car is more efficient in longer, sustainable runs. It's also easier on the vehicles engine. The same is true for your furnace.

Typically, when the temperatures drop to subzero, your furnace needs to be running for longer segments of time to keep your home at a consistent temperature. When you experience winter days in the 30s and 40s, your furnace only turns on every once and a while for short segments of time.

For example, think about temperatures in late winter — late February and early March. Often the morning is still cold, but in the afternoon the sun is warmer, heating your home and telling your thermostat that it's plenty warm in the house. Then, the sun sets and it's cold again, putting the furnace back to work for the night. In this scenario the furnace is on and off multiple times within a 24-hour cycle. When the temperatures during the day remain below zero, your home is cold and your furnace is working in long consistent runs making it easier on the furnace motor.

So, this winter, when you feel like your furnace is working overtime, don't feel sorry for it. Remember that mother nature is doing it a favor by letting it run in long stretches rather than the nagging stop-and-go cycles that wear down HVAC systems before their time.