Manassas city, VA Insulation Payback
Manassas city attic insulation, by the numbers
Manassas city sits in IECC climate zone 4 (Mixed-Humid) — a genuine mix of cold winters and humid summers, with neither one dominating the bill. For a currently uninsulated attic, DOE and ENERGY STAR recommend building up to R-60. Going from R-2 to the recommended R-60 costs roughly $3,480 installed for a typical attic (about 1,000 sq ft), and pays for itself in about 2.4 years at an estimated $1,463/year saved. Topping up the attic pays for itself fast here.
Heating vs. cooling in Manassas city
Split it out and it's roughly $1,259 a year on the heating side, $204 on cooling. By estimated insulation savings, Manassas city lands in the 50th percentile nationally. Zone 4 alone covers 825 counties in this dataset, and Manassas city comes in 252nd by savings. Virginia averages $1,342/year across the counties tracked here; Manassas city comes in 9% higher.
Where these numbers come from
NOAA's MANASSAS, VA US station, 1.1 miles from Manassas city, supplies the 4,707 HDD and 1,270 CDD this estimate runs on. Combined heating and cooling load puts Manassas city in the 51th percentile of this 3,162-county dataset. One local detail the R-value alone won't tell you: Manassas city sits in moisture regime A (humid), which can affect the vapor-barrier choice.
Already have some insulation?
If Manassas city's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-49. That smaller top-up costs around $2,280 and saves an estimated $213/year — payback about 10.7 years. Call this borderline rather than a clear win.
Quotes and materials for this job
Get more than one quote before committing. Attic access and any needed air sealing move the price around, and most contractors won't take a job below roughly $600 regardless of size - worth asking upfront given Manassas city's estimated $1,463/year on the line.
Where these figures come from
Manassas city's R-60 target and its degree-day figures both come from named federal sources - see the methodology guide for exactly which ones. The guide to what R-value actually means explains why R-60 is the target here specifically.