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Installing central a/c in house with cathedral cei
allen griggs
Member Posts: 35,700 ✭✭✭✭
My mom lives in a small log cabin. It is 29x29 feet. It has a loft that is 14x29, so it is a story and a half house.
The roof is a 10:12 pitch, pretty steep. The loft is open to the great room downstairs. So, at the edge of the loft is a wooden handrail, 3 feet high, with rails and spindles, the spindles are 2x2 and there is a 4 inch space between spindles. It is just like a railing for a deck. There is a cathedral ceiling above the great room, which is the kitchen/living room. Same peaked ceiling above the loft, ceiling peak is about 12 feet above the loft.
Beneath the loft is a big 12x14 bathroom, and a 16x14 bedroom.
My mom has central heat. The lp furnace is in the crawl space. There is duct work running to the great room, and to the bathroom and bedroom.
There is no duct upstairs, naturally, the hot air all wants to go up there in the winter.
To help keep the hot air down stairs, she has two big 52 inch ceiling fans in the great room, one above the kitchen and one above the living room.
Also there is a big 52 inch ceiling fan above the loft.
These fans are $250 cast iron American made Hunter fans, quiet as a whisper, and they really do blow the air. Like a tornado on high.
My mom is going to have central air added to the house.
Does she need them to run a vent upstairs?
If there were no duct running upstairs, and you had the downstairs nice and cool, and the loft was hot, you could light up those big Hudson Bay fans. They would blow the hot air down into the cool air in the great room, and it seems like it would force the cool air up into the loft.
Can you run a/c in this house without running a duct into the loft?
The roof is a 10:12 pitch, pretty steep. The loft is open to the great room downstairs. So, at the edge of the loft is a wooden handrail, 3 feet high, with rails and spindles, the spindles are 2x2 and there is a 4 inch space between spindles. It is just like a railing for a deck. There is a cathedral ceiling above the great room, which is the kitchen/living room. Same peaked ceiling above the loft, ceiling peak is about 12 feet above the loft.
Beneath the loft is a big 12x14 bathroom, and a 16x14 bedroom.
My mom has central heat. The lp furnace is in the crawl space. There is duct work running to the great room, and to the bathroom and bedroom.
There is no duct upstairs, naturally, the hot air all wants to go up there in the winter.
To help keep the hot air down stairs, she has two big 52 inch ceiling fans in the great room, one above the kitchen and one above the living room.
Also there is a big 52 inch ceiling fan above the loft.
These fans are $250 cast iron American made Hunter fans, quiet as a whisper, and they really do blow the air. Like a tornado on high.
My mom is going to have central air added to the house.
Does she need them to run a vent upstairs?
If there were no duct running upstairs, and you had the downstairs nice and cool, and the loft was hot, you could light up those big Hudson Bay fans. They would blow the hot air down into the cool air in the great room, and it seems like it would force the cool air up into the loft.
Can you run a/c in this house without running a duct into the loft?
Comments
First, I would make sure your A/C unit is sized to handle the total sq footage of both levels. A little too big is better than a little too small. If you go way to large the unit won't run long enough to do a good dehumidity job.
If I were doing this I would try your fan approach. I've never seen a 52" fan in a home. Those are monsters.
The vertical duct to the loft will a pain since you will have to create a wood enclosure around to hide the metal. You can always have the A/C folks come out and install the new duct if the fan approach isn't satisfactory. Yeah, it will cost a little more than if they did it all at once but I think you have a real shot using the fans.
Keep us informed. I might be facing the same situation.
But, they do look good.
At my mom's house she has a wood heating stove, in addition to the furnace.
When that thing is cranked up in the winter, it will be 72 degrees downstairs, and 85 upstairs, even with those big fans running.
The house I built for myself is a two story house, no cathedral ceiling, it is much easier to heat and a/c.
So you have built seven ... man I wish you lived out west - I would offer you a part-time job! Construction (just assembling the kit) will cost me about $75K!
At least it would be free and easy to try it that way.
There are quite a few floor vents upstairs and only one A/C unit for the entire house, though it is over-sized for the volume of the house. The return air vent is in the exact middle of the house on the lower floor. I also have ceiling fans lowered to the halfway point in the space.
It is very comfortable all year round, with about one degree variance in temp from bottom to top any time of the year. I reverse the fans in winter/summer.
I really believe the insulation of the building plays a HUGE role when dealing with a space of this height. I have R40 in the roof and R30 in the walls, my energy bill averages $219 per month and is over 4000 square feet.
Ceiling fans, proper vent/return air, good insulation, oversized unit.
Works at my place...
Can you run a/c in this house without running a duct into the loft?
Sure, but without a return air or a flow duct, it will not be cool. Moving air around is not the same as circulating it.