Expert: Ted Barnhill (Principal, Design45 LLC) - 4/2/2008

Question
Hi Ted, I moved in the current house two years ago.  Last winter, the basement was pretty warm, at about 60, very stable. However, this year, I felt the basement is colder than it was.  The temp usually is at 40-45 while my home temp is the same as that of last year.  Can you think of the reasons?  Is there anything wrong with the insulation?  My humidifier was not working well.  Could this have any impact?  Any other possible causes?  My home is 15 years old in very good condition.  Thank you for your feedback in advance.

Answer
Lin-

That is a significant change over just one year.  I would look at any changes that you made within the past year as possible contributors.  

For example, did you replace any windows or doors in your home?  Did you do any remodeling upstairs?  Did you replace or add a fireplace?  Any of these could have resulted in new air leaks in your home, which would result in a "chimney effect" of hot air leaving your house somewhere upstairs, and drawing cold air into the basement.  This basement air could come in through leaks, or through make-up air ducts in your furnace room.

If you have heating ducts in your attic, it is possible that the joints are coming apart and leaking air directly outside - this would result in the same cold basement problem.

This was a colder winter in some areas, but the difference you describe sounds like something else.  In short, look for leaks throughout your home as the most likely cause.  If you are serious about the problem, you can have a specialized contractor perform a "blower-door" test to locate all major leaks, which when corrected can save a lot of money over time.

Good luck finding your problem!  Ted