1957 Modern ranch home in Dallas, Texas. Attic currently has about 5" of ancient, degraded fiberglass and some random denim batts. We are looking to remove the old insulation, air-seal, then add new insulation. The question: is it worth it to spend $400 more for R60 or stick with R38 and put the money towards other things? Specs: 1,300 Sq/ft attic Gable vents, roof vents, not soffit vents. (no moisture issues) 3/8 plywood decking, 30 year asphalt shingle No radiant barrier HVAC with flex-duct and tankless hot water heater in attic 4/12 roof pitch, it's tight up there. Attic is not used for storage There is evidence of minor rodent activity in attic as well as silverfish. Double pane, thermal windows, but a couple old, leaky doors. Contractor we like only uses Johns Manville fiberglass, so quote is for blown-in fiberglass (is cellulose better in this application?) Plan is to have existing insulation removed, then we would personally vacuum and clean attic and air seal all ceiling penetrations, voids, etc. Motivation is both efficiency and health/peace of mind. In terms of re-insulating, is it worth it to go from R38 to R60 with blown-in fiberglass, or would that money be better spent on attic radiant barrier, or leaky doors?

Studies have shown that it is better to go with mass insulation and add a radiant barrier rather than just keep adding mass insulation. 

You'd be wise to spend some money on a blower door test, and air sealing the building. Insulation works better in an air tight enclosure than when it's being wind-washed.

Thanks guys/gals. I take this to mean that we should stick with R38 and address the other issues first.

Posted By DallasModern on 11 Jan 2017 06:28 PM
Thanks guys/gals. I take this to mean that we should stick with R38 and address the other issues first.

I did not see what anyone has made this determination and I would not assume this. I can run a quick Manual J simulation but I'll need more info. Before I take the time to develop a list are you willing to get the info even if you have do some research to get it? For example, I need to the total square feet of windows their U & SHGC values per facade and the total SF of doors per facade, and the current HVAC type efficiency and BTU outputs, r-value and heights of all walls, lower floor SF if diff than attic, slab or basement r-values if insulated....thats a start. Any good local HVAC company s/b able to do this is your other option. I hear there is quite a shortage of trades in DFW. BTW: Hows the tankless hot water heater working out? Are you using a circulating pump like TACOGenie? Did you say it's in the attic?