"kevins_news" wrote in message
...
I know that question is too open ended to really answer. Each house
will behave different. Each room will behave different depending on
windows, exterior walls, etc. But I'm just looking for some sort of
estimate.

Say it's -15C outside and +20C inside at midnight. If i left the
furnace off (gas forced air) all night, what kind of temperature could
be expected at 8am? I guess a "If it drops lower than X then you may
have issues" is the kind of answer i'm looking for.

In my house I get a drop of about 5 to 8 degrees F. Or you would end up at
15C
Ed