
As dogs are hotter blooded than us then the room has to be hotter than we would feel comfortable in, don't forget the temp needs to be hot at the ground level where the dogs are, not easy to achieve as hot air rises.
I had my first litter on Xmas morning a few years back, the whelping box was next to a radiator turned up to it's highest setting and there was an electric heat pad in the corner of the box too, I was going around in shorts and tee shirts and still too hot.
It isn't just keeping the pups warm you are aiming for the high temp wards off infections like canine herpes taking hold and killing the pups.
Some use heat lamps hanging above the whelping box to concentrate the heat in the right direction, not tried this and they seem to receive mixed reactions from members on here and those I have spoken to about them.
Good Luck