We have had to discontinue the use of the hvac since our daughter has tested positive for allergies to cats and everything else under the sun (got rid of the cat)... We have a wood stove that heats the whole house really well, too well actually.
You should really read up on the link between allergies and the use of wood burning stoves or inserts. The last thing you should be using for heat is an wood burning heat source, short of an outdoor wood-fired boiler.
Here are the results of a google search:
Search Results.
So first thing first, find another way to heat your home this winter. Then find an exterior wall and build a brumation chamber next to that wall. Not knowing how many snakes you need to brumate, it could be as simple as a cardboard box lined with Reflectix insulation. Line the entire thing except the side that will sit next to the exterior wall.
You'll be amazed at how cool it will be inside of the box. If you have a lot of snakes you could even make a walk-in closet out of Reflectix stapled to the ceiling. I know a guy who used to have a large bomb-shelter type room off of his basement. He kept one side heated to 80* or more and then simply divided the room with a drape of Reflectix that overlapped by a couple of feet. With just a thin layer of Reflectix he was able to keep the opposite side cool enough for brumation.
Actually, I think he used something other than Reflectix, but any of these products are very similar. In case you're not familiar with them, they look like bubble wrap covered in aluminum foil. All of these products are potent blockers of radiant heat.
Best wishes to your daughters health and your snakes breeding.
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Current snakes:
0.0.1 Gonyosoma oxycephala - Java locale (green)
1.2 Gonyosoma oxycephala - Jave local (green)
2.2 Gonyosoma janseni - Seleyar locale (all black)
1.2 Gonyosoma janseni - Celebes locale (Black & Tan)