Win my gratitude, solve this puzzle!
It’s gotten colder over the last couple of evenings and my lingering issue with the heat/air system in my cabin has once again surfaced. Here’s the problem: two central air units that will not work in tandem. The entirety of the problem is related to a 20′ ceiling in the living area. It looks like this
The living area downstairs actually uses the upstairs unit to heat/cool. There are 6 air registers from the up unit into this area: 2 on the ceiling of this room, 2 on the walls in this room (on the left) and 2 on the wall in the sun-room (in the background on the right).
The downstairs unit services the kitchen (in the background on the left), the downstairs bedroom, bath, and laundry room. I’ve place two 5 foot ceiling fans suspended 4 feet beneath the ceiling to move air ‘captured’ in the high ceiling. An additional 4 foot ceiling fan is in the sun room to push the air out of that room. Here is another view of that area.
The picture below is taken from the other side of the room. The there are two registers in the ceiling (between the rows of lights) and one register, that cannot be seen) above and to the right of the window on the right.
Besides being a pain in the ass, it gets expensive trying to heat this room. Right now, I’ve got the upper air unit set on 71 and the lower set on 66. Even with the unit set on 66, it is roughly 70 degrees in the rooms serviced by the lower unit.
Any suggestions you can provide would be great!
“Returns” or more specifically cold air returns should be located on the floor level where the colder air resides, not up on high where the warmer air resides.
You’re probably right! Now that the cabin is built, that upper return air handler cannot be moved (no way to get the large ducting from the unit to the floor level).
Not an expert by any means, but here is what I see:
Heat automatically rises, so any heated air from your registers will quickly rise against ceiling, leaving the cold air to stay at the floor level of 1st floor. Is your floor heated or foundation on grade, allowing cold earth to cool the floor additionally ? That in ofitself is an issue – walking on a cold surface cools us down.
A lot of window glass, most I see without any insulation covering the glazing which allows the outside cold to radiate from the glass into your living space. I’ve seen some people use ‘bubble wrap’ to help insulate both air surfaces.
Any problems with condensation ? Condensation collects at surface where hot and cold meet, like an iced beverage in a glass.
My solution – wear sweaters, long pants and some type of footwear. Heating the air space will be expensive – far easier to wear clothing and retain the heat your body automatically generates.
I like the space btw, open plan is an efficient way to design a house.
I hope you find a solution – I guess I really wasn’t much help.
Thanks. No condensation anywhere.
I built it on a slab so the floors (hardwood glued to concrete) get a mite chilly. I think the largest problem is trying to heat (or cool for that matter) the large volume of air that exist above actual living area. Moving it around with the large ceiling fans works somewhat. I’m thinking of moving to bottom thermostat (above the bottom return air vent) into another room but don’t know if I’d end up starting a new problem.
Beautiful House! Not an HVAC expert here either. You have probably already checked all of these things, but: Are your ceiling fans in the updraft mode for winter? And are they set at low, or medium speed? Are the blades cleaned at least once a month? Is there an insert in your fireplace? Do you close the damper when it is not in use? Have you checked the door jamb, and threshold seals. Do you have a doggie door? Seals tend to shrink in the cold. You can test threshold seals with a damp towel, rolled up, placed on the floor inside at the foot of the exterior entry doors (human and pet), also works on window sills. Run the heater unit. If the seals are compromised the towel will freeze, or at least frost, in a very short time. Of course, lay the damp towel on a sheet of plastic for wood floors or stained wood sills. Have you considered Mini Split HVAC systems? Sometimes it is the simplest of issues that are overlooked. I hope you can find a solution. Cheers.
I really need to recheck all that you have noted. The large ceiling fans could be doing more, but I’m working against a set of constraints that, to date, have proven inflexible. Probably a good time to note that my wife would not take lightly to being called a constraint.
The large fans move air better when they are in summer mode (forcing air directly down). When set like that they move the gathered warm air directly down into the area below. The downside to this is the air makes it seem colder below the fans than it actually is (the thermostat doesn’t lie). I turned the one closest to the stairs to force air down (leaving the other to force air up) and I picked up 3 degrees on the thermo downstairs. This actually introduces another issue/complication (other than the cold feel), if the thermostat on the lower level never triggers the heating unit then no heated air will be applied to the bedroom, bath, kitchen and mud room.
Perhaps there is a combination of fans, heat units, caulking, etc that can be configured to minimize my utility bill. One thing is certain though, the constraint mention above will ensure that the cabin stays warm!
Interesting times. There were many times in my life when staying warm and dry was unachievable; now that I’m both I complain about incremental costs……