Posted By steven moore on 30 Mar 2014 11:50 AM
Hi,
We are wanting to insulate our attic for cooler summers and warmer winters. We have had both radiant and spray foam contractors to give us a quote,we don't know which is best for upstate South Carolina. There is a split heat pump system up there and lots of for storage. I would appreciate some feedback.
Thanks,
Steven Moore
Radiant barriers are largely smoke & mirrors. They make financial sense only in low-R vented attics where the air-handler & ducts are in the attic above the insulation layer. Even then in almost all cases it's better bang/buck to spend the money on added insulation and air sealing.
If you spray foam the roof deck be sure that the foam extends all the way down to seal the soffit venting, bringing the air handler & ducts completely inside both the thermal AND pressure boundary of the house. (If you can arrange to have a blower door to verify the air-sealing of the attic venting while they are still there and set up you can get the most for your insulation dollar and save the foam guys a call-back.) If you insulated the attic without air-sealing you'll only reap half the comfort & energy benefit, with much higher latent cooling loads than you would otherwise.