I live in Roswell, GA (just north of Atlanta).

DOE says I should have R48 in my attic. Based on about 7.5 inches of blown in insulation I am guessing I have between R18 and R22.

I want to pull out the blown in (I am sucker for punishment and I absolutely hate blown in insulation.) and replace it with R30 Kraft faced batts (kraft side down) with a second crossing layer of R19 unfaced batts.

Overkill? Estimate of $xxxx for attic insulation.

At the same time I am thinking about replacement windows, estimate of $xxxx for windows.

I used HVAC-Calc to do a quick calculation of the loads for my current situation (single pane, R22) vs. having double pane replacement windows and the new insulation. I know that it is just a 'loose' calculation, but is seems like the load dropped DRASTICALLY.

My real question is that I am getting ready to replace a 2.5 ton unit and furnace, and I am wondering if doing all of this insulation work will be worth it? I seems like I can step down significantly in the sizing of the new unit. The current unit is 8 SEER and I want the new unit to be 12-14 SEER, maybe higher.

Am I crazy, will I be able to recoup the costs over 20 YRs in savings on my electic and gas bills?

- George

[Edited by BC1 on 02-18-2005 at 04:37 PM]