This common HVAC mistake could be raising your energy bill by 15%. Find out how and when to replace your furnace filter to save money.

Q: I turned on my furnace for the first time this year, and it made the whole house smell musty. I checked the filter and found it caked with dust, so I replaced it with a new filter, and the indoor ...

Changing a furnace filter regularly will improve your heating in the winter and your air conditioning in the summer.