I live in an old 1930 house in upstate NY. Department of Energy reccomends R-45 (or maybe it was R-49) in attic in my geographic region (its 20 degrees out now damnit!). I went up and measured my attic (which is 24' x 24') and it only has 3-4 inches of cellulose (attic joists are just 4 inches tall) giving me R12 or so from my calculations. I will only be living in this house 3-5 years, the question is, will I even see the benefits of adding R-30 fiberglass insulation to give me a total r-value of R-42 or so? I figure that fiberglass insulation will cost me $500 or so. Will I even get that money back over that short of a time period?
If it is helpful the price per therm for natural gas around here is like 1.15 right now (house will probably use 1000 therms in just the winter) and traditionally New York has been in the top 5 in energy costs. Thanks for the help.
Just blow in cellulose insulation over the fiberglass junk. Make sure you do not close off the ventilation at the soffits.
You will save some money and make your house easier to sell in 3-5 years when your heating bills are more reasonable. You will not save enough to pay for it in the short run, but you will get the benefits.
You will not change the climate and your house in under-insulated, so any buyer will have to plan on insulating anyway. - Really, 20 degrees is not bad.