Diagnostic Service
Insulation & Air Sealing Assessment: Find the Gaps Before You Pay to Fix Them
Blanket re-insulating wastes money on zones that already perform fine while leaving real bypasses untouched. We map R-value and air leakage zone by zone so every insulation dollar targets a documented problem.
What Number This Test Produces
R-Value Gap Map
Zone-by-zone insulation performance across attic, wall, and crawlspace
Which Rebate This Unlocks
Insulation 25C Credit (up to $1,200/yr)
Federal tax credit dollars tied directly to documented insulation upgrade scope
R-Value Verification, Zone by Zone
We check attic, exterior wall cavities, and crawlspace or basement rim joist areas separately, because a home rarely underperforms uniformly. A typical finding: an attic near its target R-value but with three or four localized voids doing most of the damage, while wall cavities show settling that a visual walkthrough would never catch. Each zone gets its own documented reading, not a single blended estimate.
The difference between a visual walkthrough and a real assessment usually shows up first in the crawlspace or basement rim joist, since these areas are rarely insulated to the same standard as the attic and get skipped entirely in a quick walkthrough. We record depth, material type, and fill voids separately for each zone, and note where insulation has compressed, shifted, or been disturbed by prior electrical or plumbing work — conditions that quietly cut a batt's effective R-value well below its rated performance.
R-Value Targets by Zone
"Enough insulation" isn't one number for the whole house — it depends on the zone and your local climate zone's code requirements. We compare your measured depth and material in each area against the target range below, so the report states exactly how far a zone sits from target instead of a vague "looks thin" call.
| Item | Target R-Value | Most Common Deficiency Found |
|---|---|---|
| Attic Floor | R-49 – R-60 (most U.S. climate zones) | Settled or gapped batts near eaves and hatches |
| Exterior Walls | R-13 – R-21, depending on cavity depth | Missing fill behind outlets, switches, and headers |
| Rim Joist / Band Joist | R-19 – R-30, fully air-sealed | Uninsulated or wind-washed perimeter band |
| Crawlspace / Basement Walls | R-10 – R-19 continuous | Uninsulated foundation wall above grade |
Diagnosing Thermal Bypasses
The biggest energy losses usually aren't low R-value — they're bypasses: gaps at top plates, recessed can lights, plumbing and electrical chases, attic hatches, and rim joists where conditioned air moves freely around insulation instead of being blocked by it. Thermal imaging combined with blower-door depressurization makes these bypasses visible as clear temperature differentials on camera, turning a guess into a documented location.
Bypasses matter more than a low R-value reading because they move air, not just heat. Conduction losses through under-insulated material are gradual; convective losses through an open bypass are continuous and often larger, since warm indoor air is actively pulled through the gap and replaced by cold outside air. That's why our findings list every bypass location by name and photo rather than reporting a single blended attic score — a contractor can't seal "the attic in general," but they can seal a documented can light and chase run.
Top Plates
Gaps where interior walls meet the attic floor.
Can Lights
Recessed fixtures that penetrate the air barrier.
Chases
Plumbing and wiring runs cut through top and bottom plates.
Rim Joists
Perimeter band joists at the foundation line.
Why Assessment Data Should Drive Scope, Not Guesswork
Without a diagnostic assessment, insulation scope is usually set by a rule of thumb — "top off the attic" — regardless of where the actual losses are. Our assessment produces a zone-by-zone priority list ranked by measured impact, so contractors quote against a documented scope instead of a visual guess, and you don't pay to over-insulate zones that were never the problem.
That specificity also protects you at bid time. A contractor quoting off a generic "needs more insulation" note has every incentive to price the largest possible job. A contractor quoting off a documented zone-by-zone gap map — with exact square footage and target R-value per zone — has to price against a defined scope, which is easier to compare across bids and harder to pad.
Seal First, Then Insulate — Sequence Matters
Air sealing bypasses before adding insulation is standard diagnostic practice for a reason: insulation installed over an unsealed bypass buries the leak path under material that makes it harder to find and fix later. We recommend a blower door re-test immediately after air sealing — before insulation goes in — so the ACH50 improvement from sealing work is verified and documented on its own, separate from any insulation R-value gains.
This sequencing also produces a cleaner before/after record for rebate documentation. If sealing and insulation happen in the same pass, it's hard to attribute how much of the final ACH50 improvement came from each step. Testing between the two steps gives you two separate, defensible data points — one showing the sealing work's contribution, and a second showing the insulation's — which is exactly the kind of granular evidence some utility programs ask for when a project claims credit for multiple measures.
Matching Upgrade Tiers to Rebate Thresholds
Federal and utility insulation incentives are typically tiered by documented R-value improvement and IECC climate zone requirements, not just "we added insulation." Our assessment report specifies the before/after R-value delta per zone in the exact format needed to substantiate a 25C tax credit claim or a utility insulation rebate application.
Some utility programs pay a flat per-measure amount once you cross a minimum R-value threshold; others scale the rebate to the size of the improvement. Either way, the number they need is the same one our assessment already produces — a documented before-and-after R-value by zone — so there's no separate inspection required just to file the paperwork.
Insulation & Air Sealing Questions
How do I know if my attic insulation is actually underperforming?+
Visual depth checks alone miss compressed, settled, or gapped insulation. A diagnostic assessment combines an R-value depth check with thermal imaging during a blower-door-induced pressure differential, which reveals bypasses a visual inspection alone cannot see.
What's the right order — air sealing first, or insulation first?+
Air sealing first. Adding insulation over unsealed bypasses traps air movement pathways under new material, wasting insulation dollars and leaving the leakage in place. We seal first, then re-test with a blower door before insulation is installed, so you can verify the sealing worked before spending on insulation.
Will air sealing my house cause indoor air quality or combustion safety problems?+
It can, if done without follow-up testing — a tightened envelope changes how combustion appliances draft and how fresh air enters the home. That's why every air sealing project we assess should be paired with combustion safety and ventilation testing after the work is complete.
What are thermal bypasses and why do they matter more than low R-value?+
Thermal bypasses are gaps that let conditioned air escape directly — top plates, recessed can lights, plumbing and wiring chases, and rim joists. A wall can have adequate R-value on paper and still perform poorly if bypasses are moving air around the insulation rather than through it.
Other Diagnostic Services
Insulation assessment is frequently paired with these tests for a complete envelope picture.
Whole-Home Energy Audits
BPI-standard diagnostic-grade audits
BBlower Door Testing
Air leakage measured as an ACH50 score
TThermal Imaging
Infrared scans reveal hidden thermal loss
HHERS Ratings
Official home energy scoring
UUtility Rebates & Tax Credits
25C, HOMES, HEEHRA, and utility programs
CCombustion Safety & IAQ
Backdraft, CO, and ventilation testing
NNew Construction Verification
Duct blaster and code-compliance testing
MMultifamily & Commercial Assessments
Scaled diagnostics for larger buildings
Find Your Home's Real Insulation Gaps
Book a zone-by-zone insulation and air sealing assessment before you spend on upgrades that miss the actual problem.