Where insulation jobs fail
Insulation failures show up on your energy bill or in moisture damage, sometimes both. The energy bill problem is usually about air sealing - or its absence. The moisture problem is usually about vapor management done incorrectly. Both are more common than they should be.
The 10 pitfalls
Skipping air sealing
Air sealing is the single highest-return item in any insulation project.
Under-insulating relative to climate zone recommendations
Adding R-30 in an attic that should have R-49 based on your climate zone leaves significant energy savings unrealized.
Wrong vapor management for the climate
In cold climates, vapor barriers belong on the warm side of insulation (interior).
Insulating over existing moisture problems
Wet insulation does not insulate and creates mold conditions.
Off-ratio spray foam installation
Spray foam is a two-component product.
Installing dense-pack cellulose without checking existing wiring conditions
Dense-pack blown-in can put pressure on older knob-and-tube wiring.
Not insulating the attic hatch
The attic hatch is a direct conduction path between conditioned and unconditioned space.
Ignoring the crawlspace thermal boundary
Whether the crawlspace is conditioned or unconditioned determines where the thermal boundary should be (crawlspace ceiling vs crawlspace walls and floor).
Not verifying installed depth after blown-in installation
Blown-in insulation installers bid on R-value.
Missing available tax credits and rebates
The Inflation Reduction Act energy efficiency tax credits cover 30% of insulation and air sealing costs.
The bottom line
Always include air sealing with attic insulation. Verify R-value targets against climate zone recommendations. Do not insulate over moisture problems. For spray foam: use certified installers. Check for available tax credits - they are significant for this type of work.
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