My new to me 1977 style, Texas U shaped ranch house, is going through the hottest summer on record, with heat index numbers between 103 & 115 everyday with no end in sight.
My AC is running full time (it only cools down to 82 at night) and I keep the thermostat at 81. My electric bills are running over $300/ month. I have had the old AC condenser unit replaced and there are ceiling fans installed in every room except the kitchen where ceiling height is only 8'.
In order to reduce the electric bills, I have read up on the current Solatube brand Solar powered fans (called Solar Star) that can be installed in place of an existing roof vent as seen here: http://www.solatube.com/homeowner/solarstar.php?gclid=CMzQhc_8rJwCFSYoawodR1iUjw. Being solar powered, it costs nothing to run, so I figured it might just be the answer to the maiden's prayer.
The solar panel is integral with the fan housing and it makes the single unit easy to install with no additional wiring needed. Each fan is rated at 850 cfm. According to their sizing chart, I would need 2 fans (near either end of the 4 in 12 gabled roof) on the longest straight roof section facing the street. There appear to be adequate soffit vents in the 18 inch roof overhang on both sides of the slope.
Has anyone had any experience with these Solar Star fans from Solatube?
Specifically, do they work as advertised to adequately cool the attic? Is a combined total of 1700 cfm for both fans enough to do the job for 1500 sq ft of floor space under that roof?
Next, since it has been so hot, I haven't dared to get into the attic to scope things out. I assume that whatever insulation there may be is more than likely inadequate and will require either supplementation or replacement to reduce heat flow from the attic to the rooms below. Does it matter if I install a different type of of insulation (like foam panels) over what ever is there now? I surmise that the original insulation is either batts or blown in loose for that 1977 age bracket. Any comments on this approach?
Finally, I have read about another product that is a special radiant conduction barrier that claims to reduce radiant heat conduction from the attic to the rooms below if placed on the attic floor OR reduce heat conduction from the roof surface to the attic space beneath the roof & hence further reducing conduction to the rooms below.
95% of the heat transfer from the roof to the inside of the house is based on infra red radiant conduction, so this approach seems to have merit. Walls & windows are another issue altogether. My question here is has anyone used this material and does it meet the claims made for it? Their products are called radiant barriers as shown here : http://radiantbarrier.com .
Has anyone used this and if so what do you think of it?
Any help on this would be greatly appreciated. :)