
Just about the Whelping box, is it open or covered up in some way.
If you have a very open plan (or even when not) house bitches like to have a den, and ti also helps contain heat.
Can you put a dining table over the whelping box? You can then drape a large throw or sheet over to enclose it making a cosy den.
You will need puppy pen panels anyway for a larger area once mobile and to sue to make a safe area outside for playtimes once around 5 weeks. These could be put around your whelping box giving more height and then a sheet draped over to make the den.
Obviously you still need easy access so might want to add the cover once whelping is complete, but still gives you room for checking and cleaning.
Also regarding temperature this can vary with breed.
For example at whelping I would keep temperature high, but by about 4 days neither bitch or pups in my double coated northern breed can stand temperatures over 65'F though I have the heat pad in the box for them to move to they are all spread out as too warm.
Since 10 days old room temperature has been down to 60'F, and the heat-pad was removed at two weeks.
They will be going into unheated kitchen at 3 weeks. They will start going outside at 4 - 5 weeks as long as it is above freezing and dry.
On the other hand some breeds crave heat.