Trying to figure the best route to cool and heat a third (top) floor of a house with inadequate forced hot/cold air heating up there:
- Supplemental fans in the third floor ductwork. That would be my preference but most every HVAC supplier around says “it doesn’t work.” Whether it does or doesn’t work, most of the fans seem to be for round ductwork and of course the house has rectangular ducting. This would be the cheapest solution if it worked. I do know the Home Depot solution, the fans that attach at the ends of the registers, don’t help much. I wonder if it would help to add a inward-sucking fan in the air return ducting.
- Low profile A/C units in the windows. At least you could see out a bit. But you wouldn’t get heat in the winter. And it’s about 12″ high for the most commonly available, a Sears unit, vs. about 15″ for most regular AC window units. Not much visibility savings there. But you can try it for $200 to $300 for each of the two rooms. And only one of the two rooms has a rear-facing window.
- Putting a through-the-wall AC unit through the 6-in-12 roof. The rooms have 4′ knee walls then the roof. Not sure about waterfastness no matter how good the flashing. It would preserve the views out the windows but it wouldn’t provide any winter heat. On the other hand, you can add baseboard electric, or even standing quartz heaters, pretty cheaply.
- Split unit AC with compressor outside and two wall units (air handlers). Most of the literature is unclear if you can hang two units off one compressor but I think I’ve seen it done in Asia and the Caribbean. On this one, I can see a big Ka-Ching in the cost column.
Appreciate comments on what has worked for you. The room is guest quarters for occasional visitors, so energy efficiency isn’t crucial; it’s being used maybe five or six days a month.
Replies
"# Low profile A/C units in the windows. At least you could see out a bit. But you wouldn't get heat in the winter. And it's about 12" high for the most commonly available, a Sears unit, vs. about 15" for most regular AC window units. Not much visibility savings there. But you can try it for $200 to $300 for each of the two rooms. And only one of the two rooms has a rear-facing window.
# Putting a through-the-wall AC unit through the 6-in-12 roof. The rooms have 4' knee walls then the roof. Not sure about waterfastness no matter how good the flashing. It would preserve the views out the windows but it wouldn't provide any winter heat. On the other hand, you can add baseboard electric, or even standing quartz heaters, pretty cheaply.
# Split unit AC with compressor outside and two wall units (air handlers). Most of the literature is unclear if you can hang two units off one compressor but I think I've seen it done in Asia and the Caribbean. On this one, I can see a big Ka-Ching in the cost column."
You can get any of those units as heat pumps so that you will get heat in the winter from them.
But for ocasonional use AC with baseboard might be cheaper.
And the split units are called Ductless Split (or Mini Split) systems. And I yes you can get to work more than one inside unit.