The average homeowner doesn’t often think about this on a daily basis, but modern homes are constructed with energy efficiency in mind. This means they’re built tightly, so they don’t allow any conditioned air to leak out. Factors such as proper insulation, weatherstripping, and keeping your doors and windows shut while you run your HVAC system all help maintain good energy efficiency, too.
But keeping your windows and doors shut won’t do that much good if either of them need upgrading! Drafty windows or doors losing their seal could cost your home a lot of its conditioned air. So no matter the season, you might relatively be turning your thermostat way lower or way higher than it needs to be.