Duct Leakage Testing Andover MA - Quick Facts
Local energy code in Andover
- Andover enforces the Massachusetts Stretch Energy Code for new construction and major renovations. IECC Climate Zone 5A.
- Massachusetts has three energy-code levels - base (2021 IECC), Stretch, and Specialized (Opt-In) - and Andover is on the Stretch Code.
Duct leakage requirement in Andover
- Andover permits under the Massachusetts Stretch Code cap duct leakage at 4 CFM25 per 100 sq ft of conditioned floor area.
- Testing is required unless the entire duct system and air handler sit inside conditioned space; a rough-in test and a final test may both apply.
- Results in 24-48 hours with clear pass/fail documentation, filed with the Andover building department.
- From $350 for the first ducted system, often bundled with blower door testing and a full HERS rating.
2026 Mass Save incentives in Andover
- Duct and blower door results feed the HERS rating that unlocks Mass Save all-electric incentives: $7,500 to $25,000 per new single-family home and $1,000 to $3,750 per multifamily unit.
- Incentives require a Mass Save-approved, RESNET-certified HERS rater.
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Duct Leakage Testing Andover MA
Certified duct leakage testing for Andover, measured with a calibrated duct blaster and documented for your permit and HERS rating.
Duct Leakage Requirements in Andover
Andover enforces the Specialized Stretch Code, so every duct must test at 3.0 CFM25 per 100 square feet regardless of where it runs. Our raters measure your ductwork in CFM25 and document a clear pass against the 3.0 CFM25 per 100 sq ft on all ducts limit.
| Project / code tier | Duct leakage limit | What is tested |
|---|---|---|
| Base energy code | 4.0 CFM25 / 100 sq ft | Ducts outside conditioned space |
| Stretch Code | 4 CFM25 / 100 sq ft (total) | Total leakage or leakage to outside |
| Specialized Stretch Code | 3.0 CFM25 / 100 sq ft | All ducts, regardless of location |
| Ducts fully inside envelope | Test generally not required | Air handler + ducts in conditioned space |
IECC Duct Leakage Thresholds Reference
Beyond the Massachusetts tier that applies in Andover, these are the federal IECC duct-leakage limits across code editions. All values are CFM at 25 Pascals (CFM25) per 100 sq ft of conditioned floor area (CFA) unless noted.
2009 IECC
| Test stage | Measurement | Leakage limit |
|---|---|---|
| Postconstruction Leakage Test | Duct Leakage to Outdoors | ≤ 8 CFM25 / 100 sq ft CFA |
| Rough-in with AHU | Total Duct Leakage | ≤ 6 CFM25 / 100 sq ft CFA |
| Rough-in without AHU | Total Duct Leakage | ≤ 4 CFM25 / 100 sq ft CFA |
2012, 2015, 2018 & 2021 IECC — Prescriptive Paths
| Test stage | Measurement | Leakage limit |
|---|---|---|
| Postconstruction Leakage Test | Total Duct Leakage | ≤ 4 CFM25 / 100 sq ft CFA |
| Rough-in with AHU | Total Duct Leakage | ≤ 4 CFM25 / 100 sq ft CFA |
| Rough-in without AHU | Total Duct Leakage | ≤ 3 CFM25 / 100 sq ft CFA |
2015 & 2018 IECC — Performance Path (Cost Compliance)
Leakage testing is required unless all ducts and air handlers are located entirely within the thermal envelope. There is no pass/fail threshold for duct leakage on the performance path.
2024 IECC — Prescriptive Path
| Conditioned floor area | Condition at test | Total leakage limit |
|---|---|---|
| >1,000 sq ft CFA | Space-conditioning equipment not installed | < 3 return grilles: ≤ 3 CFM · 3+ return grilles: ≤ 4 CFM |
| >1,000 sq ft CFA | All components installed | < 3 return grilles: ≤ 4 CFM · 3+ return grilles: ≤ 6 CFM |
| >1,000 sq ft CFA | Equipment not installed, ducts entirely in conditioned space | < 3 return grilles: ≤ 6 CFM · 3+ return grilles: ≤ 8 CFM |
| >1,000 sq ft CFA | All components entirely in conditioned space | < 3 return grilles: ≤ 8 CFM · 3+ return grilles: ≤ 12 CFM |
| ≤1,000 sq ft CFA | Equipment not installed | ≤ 30 CFM |
| ≤1,000 sq ft CFA | All components installed | ≤ 40 CFM |
| ≤1,000 sq ft CFA | Equipment not installed, ductwork entirely in conditioned space | ≤ 60 CFM |
| ≤1,000 sq ft CFA | All components entirely in conditioned space | ≤ 80 CFM |
How Duct Leakage Testing Works in Andover
A duct blaster seals off your HVAC system and pressurizes it to 25 Pascals. The airflow needed to hold that pressure is your leakage rate in CFM25 — the lower the number, the tighter the ducts.
Common Sources of Duct Leakage We Check in Andover
Most duct leakage comes from a short list of predictable weak points. Knowing where to look is what turns a CFM25 number into a fixable list of locations.
Boot & register connections
The joint where a duct boot meets the drywall is the single most common leak point — often left unsealed behind the register grille.
Plenum & air-handler seams
Sheet-metal plenums and the cabinet of the air handler leak at seams and access panels unless mastic-sealed.
Disconnected flex runs
Flexible ducts can pull loose at collars or get crushed above insulation, dumping conditioned air into the attic.
Panned-joist returns
Return cavities framed from floor joists or wall studs are notoriously leaky and can draw in unconditioned air.
Building-cavity returns
Using framing cavities as return ducts pulls air from attics, garages, or crawlspaces instead of living space.
Trunk-line joints
Long supply trunks flex and separate at joints over time, especially where they were only taped rather than sealed with mastic.
Why Tight Ducts Keep Heat In Your Andover Home
In Andover, leaky ducts quietly waste a large share of what your furnace or heat pump produces, sending warm or cool air into spaces no one lives in.
Once the ducts test tight, the heat you pay for stays in the living space, the system cycles less, and utility bills settle down.
What Your Andover Duct Test Report Includes
You get a document your building department and HERS software will accept the first time — not just a number.
- ✓The test method used (rough-in or post-construction) per ANSI/RESNET/ICC 380
- ✓Documentation formatted for your HERS rating and building-permit file
- ✓A punch list of leak locations if a re-seal and retest is needed
- ✓Measured total duct leakage in CFM at 25 Pascals (CFM25)
- ✓Leakage normalized per 100 sq ft of conditioned floor area
- ✓Clear pass/fail against the 3.0 CFM25 limit that applies in Andover
Best Fit for Projects Like
- Projects in Specialized-Code towns that must hit 3.0 CFM25 per 100 sq ft on all ducts
- Custom homes with complex duct runs that need verification before final inspection
- Heating and cooling alterations that add or extend ductwork in Andover
- Andover new-construction homes needing a duct test to complete the HERS rating
- Homes switching to a heat pump where duct tightness protects the new system's output
Duct Leakage Testing Andover MA Facts
- Ducts newly installed as part of an alteration must also meet Section R403 under the state Technical Guidance.
- The Total Leakage test seals every register boot and captures all leaks — inside the home and out.
- Supply-side leaks push expensive heated or cooled air into cavities where no one benefits from it.
- A duct leakage tester, or duct blaster, pairs a calibrated fan with a precise pressure sensor to quantify how leaky the ducts are.
Trusted for Duct Leakage Testing Andover MA
Our Massachusetts Service Locations
Serving clients from our Massachusetts locations in Everett, Somerville, and Framingham.
Everett Location
371 Main St
Everett, MA 02149
Somerville Location
519 Broadway
Somerville, MA 02145
Framingham Location
68 South St
Framingham, MA 01702
Duct Leakage Testing Andover MA FAQ
Get Started With Duct Leakage Testing Andover MA
Fast scheduling and permit-ready CFM25 reports for Andover and all of Essex County.
Call 617-501-6788HERS Ratings Across Andover and Nearby Communities
Home Energy Efficiency Consultants rates new homes, additions, and major renovations throughout Andover — including Andover Center, Shawsheen Village, Ballardvale, and West Andover. Every Andover project is filed with the Town of Andover Building Division, and we handle the energy model, blower door and duct leakage testing, and the compliance paperwork from start to finish.
We also serve the communities right around Andover, including North Andover, Lawrence, Tewksbury, Wilmington, and Reading. Our Everett office at 371 Main St is the closest of our four Massachusetts locations — see our Everett office or call (617) 501-6788 to get a Andover rating on the schedule.
Andover Specialized Energy Code — HERS Index Targets
Andover enforces the Massachusetts Specialized (Opt-In) Energy Code. The required HERS score depends on fuel type and project scope — a lower index is stricter.
| Project type | Mixed-fuel | Mixed-fuel + solar | All-electric | All-electric + solar |
|---|---|---|---|---|
| New construction | HERS 42 | 42 | 45 | 45 |
| New construction — embodied-carbon credit | 45 | 45 | 48 | 48 |
| Accessory dwelling unit (ADU) | 52 | 55 | 55 | 58 |
| Major alteration / renovation / change of use | 65 | 70 | 70 | 75 |
A HERS rating is triggered by new construction, additions over 1,000 sq ft (or more than 100% of the existing conditioned area), and Level 3 alterations over 1,000 sq ft affecting more than 50% of the home. New homes must also pass a blower-door test at 3.0 ACH50 and include electrification-ready wiring for heat pumps, EV charging, and solar. We model your Andover project up front so you know the exact target and the fastest path to hit it — call (617) 501-6788.
