I'd like to build a tier system for primary/secondary/racking in a rather large closet that is in the garage. This closet also houses our gas hot water heater. Is this a bad idea?
Got to think about venting CO if you use gas burners to heat while you're working inside the closet, otherwise it might become a sort of crypt for your corpse. Keep it safe!
just reread SORRY! monitor the temperature in there while the water heater is running and make sure it doesn't get too hot, but it should vent out and be insulated enough that fermentation will be fine in there.