Smoke and Mirrors! ok, I've found these solar guards at Wal-mart that go inside car windshield that reflect the sun back out. They had a large size that was by far cheaper than others for $2.88 U.S. dollars. The size is 27 inches by 67 inches and they only have aluminum reflection on one side. So, I bought 3 of them and I'll afix them in places that will reflect back on the drums, and missing those, light will reflect toward the shelves. I'll make them removable so that I can indeed reflect light back out the glazing in the summer and reflect inside the solar shed during the winter. If this experiment goes well, I'll spring for the price of some brand named, like Reflective insulation and do it up right. I'll post back soon my early results and if I can figure out how to post a picture, I'll do that too. ~Tom

If you have continous run soffit vents as well as a continous run ridge venting, then typically you would have an air space between the insulation and the roof sheathing with most insulation types. Most use styrofoam or plastic baffles stapled to the underside of the sheathing inbetween the rafter spaces that insures that the insulation wont interfere with that air space. Air is drawn up through the soffit vents , through the air space/baffles, and out through the ridgeventing. This helps to keep hot air out in the summer, and to keep condensation out in the winter months. A radiant barrier sheeting draped on the underside of the rafters will keep heat gain from entering the space by keeping the heat confined to the rafter space w/ the hot air traveling up and out through the ridgeventing. For foam applications, you will have to research what method is being used in your area, as in some areas they utilize the air space w/ baffles and foam up to that to keep the air space intact. In other areas they fill the rafter space solid w/ no venting at all. Check in w/ reputable foam outfits in your area as well as your areas requirements from the building dept. Hope this helps. Here is a link that might be useful: radiant barrier

You should have a dedicated water heater (could be a 30 gallon, doesn't have to be 40) for your radiant heat, some kind of pump and thermostat to control the temp. The tubing shouldn't be expensive, but that sounds like a pretty good deal if that $700 includes all the parts. If it is just labor, no way. It should take no more than three hours to do. What state do you live in? If you live close to me, I could give you a few resources of who to call. Hubby does radiant heat on a large scale. He gave me all this info.

I"m researching this sealed attic concept for a renovation/addition in Virginia. It seems to me to make sense that if you seal your attic and your mechanical equipment is up there it will have less heat or cool loss - and the upstairs will be improved as it will be against a semi conditioned attic thus resulting in less heat or cool loss. I guess if you only insulated your ceiling - just the fact that your ac unit is running in a 130 degree attic or your furnace is running in a 30 degree attic - means you are losing cool/heat that you are paying for. A sealed attic (spray foam roof deck) would seem to be more efficient and result in lower energy usage. the closed cell/open cell decision and the the thoroughness of the sealing of the envelope would seem to be critical. Also - what are the real ramifications of roofing lifespan reductions due to hot sheathing. Will the sheathing really be that much hotter than when it isn't insulated under the roof sheathing? I suppose the heat cannot flow into the attic - but at some point doesn't the attic heat up to the point where there is no more heat flow and the roofing is as hot as it would be with a sprayed deck? HOw might metal roofing effect this consideration? What about solar PV or Hot Water above a sealed attic (seems like the solar hot water could only benefit - i guess the pv panels could get too hot if not spaced enough to 'cool' off. any thoughts?