I'm in the UK and I live in a tenement flat which is quite difficult to heat. I'm using the same 'bonding' solution you are; when it's playtime her pen is beside the radiator and the heating is turned on an hour or so before we bring her out. She doesn't seem interested just now in exploring much, but she's only been here for a week and is only a babyhog still.
When she starts doing nothing we let her rummage inside our dressing gowns and watch TV with her. We've usually 'hand fed' her some bugs while she's been in her playpen and if she still has more to have we'll interrupt her digging to offer her some more.
We have her against our clothes/scent during bonding and remove her from her vivarium and all of its familiar smells. We use a blanket to protect our clothes though she usually does the toilet while in her playpen so we wait until after then to handle her.