insulating after airconditioning-attic
I own a 1 1/2 story house built approx. 1980. At the time it was state of the art energy efficient. I never had any ice cycles or ice problems. Recently I had airconditioning installed. It was placed in the attic. Since then I have had difficulty with icecycles on the north side. I think the problem is heat loss though the insulated ducts for the airconditioning in the attic and knee wall space. I have hot water heat.
I am wondering what would be the best way of correcting the problem. Currantly I’m thinking that insulating with a styrofoam with a reflective covering on the joist. This would move the insulated envelop to the roof but still allow ventilation. Is there potential moisture problems with this method. Would another method be preferable.
allywood
Replies
if you suspect heat loss from condtioned space into and through insulated ducts in the attic, why not prevent the heat loss by blocking the registers? this can be accomplished by either using magnetic sheets to cover the registers during heating season, or by installing a layer of insulating foam sheet and vapor barrier between the register and opening. (which is more work)
this would cost much less than reinsulating the attic, and address the heat loss problem.
Would another method be preferable.
Blown in celulose would be my choice. It can go on and between the ducts. Add as much as you'd like.
Beer was created so carpenters wouldn't rule the world.
good point.
allywood
Not only do you have the ducts themself. But you also have all of the openings where the duct go through the ceiling/walls and connect to the vents and air can escape around them.
Also you have all of the joints of the ducting that can leak. And the surface of the HVAC equipment.
A lot of people recommend bring the equipment into the conditioned spaced by insulating the roof.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Do you know of an reference on how much to insulate and what would be the best method. I thought there was a letter to the editor in fhb that discussed it but I could not find it. No only is there the problem with the holes for the hvac systems but there are more "ceiling light which also act as airleaks.
thanks,
allywood
You can look at these that say Conditioned Attic.Also the ones with cathedral ceilings.http://www.buildingscienceconsulting.com/designsthatwork/default.htmAnd here.http://www.buildingscienceconsulting.com/resources/roofs/default.htm.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Thanks for the references.
allywood