The fans will suck blowing the heat right out the window. This where Hydraulics really help in the Winter. You don't have to worry about exahust, loosing heat plus the tanks radiate off some heat too. I was lov'n mine today wiTh the rain coming down I did not miss a beat working.
I would not use a heat pump with the fan system. I use a big 220v light now and then one that was on a tennis court it creates a ton of light and makes some heat right under it. It gives a little feeling of Sun light in the winter. You could do that with the 110 v work lights too make a little bank of them right above were you carve. I'm not sure what you have for amps going out there right now the fans provably draw a bit. If you are going to load things up start the fans so the draw passes then turn on the lights. You could turn on the lights and warm up the room pretty quick. Turn them off to start the fans then put them back on. You will be throwing money out the window with any type of heat intended to heat the air. If I did not burn wood I would go broke this place could cost as much as $900 to heat the whole place in the middle of winter.
There are some systems designed to heat right where you are the have them above cashiers in Home Depot. All that stuff is gas though. I think the contractor lights could work like that for you it's a radiant and direct heat not heated air.
Hydraulics! Quit screwing around. You can carve in comfort and the tools last for ever. The new 5hp has more chain speed than the one I run it's super nice. I'm hoping to make a sawdust compactor to run off of mine too. Press a button and go! No adding fuel, little noise, no exhaust, add oil once a week it's the best thing going for studio carving.
Good luck with the heat Joe. Try one light see what you think.
Keep your saw in the Wood!