Cathedral ceiling insulation for A/C efficiency


Old 04-18-16, 01:01 PM
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Cathedral ceiling insulation for A/C efficiency

Hi all, not sure if i'm posting this in the correct location but here goes.

I have a home built in the 50's here in California and would like some advice regarding the insulation for air conditioning. The home is about 1300 square feet, on a raised foundation with a crawl space, and currently has no insulation in the walls, which instead of drywall are composed of that rougher and more sturdy rock like material board. The living/dining/kitchen area is under a cathedral ceiling with no insulation as well. The bedrooms are under a regular dropped ceiling with old brown blown-in insulation between the ceiling joists. Currently have the old 1 ton split AC system that came with the house. Neither heating nor cooling the home is effective with the current setup.

I would like to avoid tearing up the walls at all costs and was wondering if placing 2" rigid foam insulation in the cathedral ceiling,then boarding over that to keep the "cathedral ceiling look", would be worthwhile and a cost effective way to raise the efficiency of the AC. Or would I be better off insulating the Crawl Space? As my budget is limited, I would like to start with the most effective method of getting my air conditioning under control and slowly move to upgrading the other factors such as windows and doors.

Suggestions and advice are greatly appreciated.
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Old 04-18-16, 02:25 PM
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Is there an attic above the cathedral ceiling? Are you sure you have a 1 ton split system? From the 50's, that would make it over 60 years old??
Old 04-18-16, 03:17 PM
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I moved this thread to the insulation forum as it's really a question on overall insulating instead of a direct A/C question.

If you're primary concern is A/C..... you should start from the top and work down leaving the crawlspace until last.

You don't want to rip out the cathedral ceiling but want to put foam board on it and then recover it ?
That sounds like a lot of work.

If there is no attic above the cathedral ceiling... spray foam and new sheetrock would be the most effective.
Old 04-18-16, 03:48 PM
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There is no attic above the Cathedral Ceiling for sure. It is a sealed, non-vented cathedral ceiling.

Cant say how old the AC system was in when we first bought the home 2 years ago. Definitely pre 90s.

I didn't want to rip out the upright walls. The cathedral ceiling is technically open now so nothing to rip out. I would like to keeps to the open ceiling aspect with the tongue and groove wood look. Can i spray foam between the rafters with furring strips on the inside of each rafter, then run new t&G across the firing strips?
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