I have restored all the hot, cold, gas, gutter, in my house. I have not setup the heat up till now and I have been using a gas stove for heat. The gas stove is unvented (free standing unit) and runs all day/nite because the house is block and won't warm up otherwise. I usually use a gas wall furnace, but it's not hooked up and I'm trying to get a new attic based furnace. Is there a health hazard doing this? And is there a detector of some type that might tell me if the air is not good?