I have a 4-seasons room approx 15'x15' with a 12' ceiling (observitory all glass) I installed this room on a deck in the rear of my home seperated by french doors and a single door to a kitchen area. After last year's install I used a gas fired garage heater that was ventless until I could come up with a better system for this room (wanted to use the room last winter) as many of you already can surmise, the room had the smell of gas and created film on windows. I have researched several options including direct vent --through the wall units manufactured by Williams and several other available units. The problem is I have a 12" base around the room from the floor to the start of the windows that won't allow a direct vent (to short) Another option is the 2 piece unit like (MItsubishi) that is electrical and the main compressor unit is outside. Althogh this is possible, I live in Wisconsin and I have found that these units won't produce heat in sub-zero weather. My idea is to have installed a 30,000 btu (HOT-DAWG) unit in my basement directly under the wall seperated by both doorways. The venting could run straight up and push heat into this room that would be dedicated to this room only. When we use this room, all the doors are open to all other rooms---when it's lights out, we close the doors and turn the temp down into the low 50's. Now I find that Goodman has a more efficient 48,000 btu 2-stage furnace that I would like to run the same way as the Modine Hot-dawg. I am certainly not a contractor and so to old to be hanging this unit on my own, I would only use a qualified pro to make the install. My quarry to you is this idea possible ? Do I have to worry about issues of air returns or with some advise can this idea work ??? I am a retired Buff pilot and just want to watch the Pack and stay warm this winter---can anyone help ???? Thank You