The Wind Chill Factor was designed to measure how cold blowing air
feels on bare skin, and if I remember right the folks who originally
created it just took a bunch of military recruits and blasted cold air
at them and asked a lot of questions. It's not very scientifically
accurate but it's better than nothing when deciding how much clothing
to wear on a cold day.

As others have said, if a house is poorly insulated and/or has a few
leaks, wind will cool the house down much faster. It's pretty easy to
walk around a house on a cold, windy day (try it barefoot) and see
where the air leaks in. It's pretty cheap and easy to caulk gaps, to
put (or replace) weather-stripping in the windows and usually not that
much work to unroll some extra insulation in the attic (Home Depot has
been selling 25 feet of R-30, which is a lot of insulation to add, for
around $16 a roll).

Oh, and if you have closets on outside walls, keeping the doors closed
with help a bit since closets rarely are heated except for what comes
in from the room. Though you might want to take out your clothes the
night before so they're warmer when you get dressed in the morning.

I assume you made sure that all the vents are open...

Shaun Eli
www.BrainChampagne.com