Personally, I'd avoid doing that unless you make some modifications. I had a large BCI for many years, & my house is set to 70* in winter. She enjoyed wrapping around me while I watched a movie, & while she got some warmth from me, I also used a heating pad under her & also a blanket over her to hold in my heat & that of the heating pad. She obviously enjoyed that (so did I) & my biggest challenge was getting her back into her enclosure.My BCI remained healthy, so I'd say that worked fine for me- the longest she was out like that was about 3.5 hours- and I'm sure boas experience similar conditions in the wild too, so as long as yours is healthy to start with, maybe this would work for you too. Just keep in mind that 65* is cooler still- maybe a portable heat lamp nearby would work for you? Or a small space heater?