Thanks bungeeii. I actually made contact with a spray company that had a certified Energystar auditor working with them. They did an energy audit today and took measurements to estimate the job. They estimated the following rebates, and will put these terms in the contract as stipulations before any work is done: 1. audit costs $400 with $125 rebated if the work is done. 2. $1000 govt rebate off the top for a thin barrier spray in the attic floor. I don't have the exact terminology in front of me, but it is basically a skim coat of foam onto which is blown cellulose or other for attic insulation. 3. up to 50% rebate ($5000 max) depending on the results of the energy audit. Because I have high efficiency furnaces and on-demand hot water, she says that I will rate at a 25%+ energy savings, which will put me at the 50% rebate from the govt. The rebate takes about 10 weeks. So, in their example, if the job costs $11,000, I pay $10,000 plus the $400 for the audit ($1000 "instant" rebate for the attic thing), then get $5000 + $125 back in 10 weeks. After my contractor subtracts out what he was charging me for fiberglass, I should net out at a very reasonable number. The people today were my third estimate, and I believe they were the most knowledgeable about the right thing to do. I'm just waiting till next week for their estimate. Thanks again, I think I'm finally getting the right game plan together!

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?

Open cell polyurethane spray on the underside of your roof will be way below the minimum recommended R Value for new wood framed homes, according to the US Department of Energy. If you have typical 2x6" rafters, you will only be getting R20 vs. the minimum recommended R30. actually 2x6 rafters are 5.5" filling the rafter bay with 6" of open cell foam meets the catherdalized insulation standard. foam covers faces of 2x's to minimize thermal bridging. see pictures linked in my previous post. Plus, unless the job includes sealing all the openings into the attic from the exterior, you will not be getting the full benefits of the insulation. (See linked document.) document linked is promoting rigid foam sheathing to exterior of roof. OP is applying foam to interior of attic at roofline. when roofline is foamed the air and thermal barrier is now at the roofline not the attic floor. leakage sites that were problematic with insulation at attic floor are no longer sucking (negative pressure) from the conditioned space below. Only if you have those leaks sealed and use closed cell foam does spraying the underside of the roof make economic sense. open cell is used in hot humid climates. not closed cell. Unless you have HVAC in your attic, you will likely be getting a much better return by insulating the attic floor as suggested above. Unless being the operative word... 90% of homes in the south have hvac in attic. and ductwork in the attic. putting equipment and ductwork under the insulation (foam on roofline) allows equipment and ducts to perform. putting foam on attic floor still puts equipment and ducts in 130 degree attic. Spraying R20 under your roof on the Georgia shores and calling that fine and dandy? I wouldn't have anything to do with either of these contractors. If you want an impartial assessment, read the linked materials or contact an energy consultant in your area. Resnet is a good source for an independent energy rater. best of luck op

contractor's first job that used spray foam insulation. always, always,always a red flag. new spray foam installers hardly ever get an even application of foam, so depth of foam varies. they also (if your foam install is on the roofline of the gargae...which isn't clear at all in your post) never get the install air tight. most leakage is at the roof to attic floor (eaves/soffit) area. garage ceiling?? where is foam...roofline? open cell foam should have been 7" thick to meet code in La. R-11 isn't even code for walls anymore. 7" @ R-4 per inch will be R-28. foam has to meet code just like any other insulation product. is this attic shared with the attic of the house? does the rest of the house have foam? did newbie seperate garage from the rest of the house? how will you heat the space in the winter? water heater is electric...and inside the frog? the added cost of $150-200 monthly quickly adds up to what you would have paid an experienced foam installer. take a couple of pics & post if you get a chance. best of luck.