Duct Leakage Testing Milton MA - Quick Facts
Local energy code in Milton
- Milton has been an Opt-In (Specialized Code) community since January 1, 2025, layering electrification requirements on the Stretch Code; it sits in IECC Climate Zone 5A.
- Beyond the Stretch baseline, new mixed-fuel homes must be pre-wired for future electrification and add on-site solar where there is significant unshaded roof space.
- All-electric new homes must use heat pumps for space heating and hot water; fossil-fuel homes over 4,000 sq ft must reach net-zero (HERS 0), and new multifamily over 12,000 sq ft must meet Passive House.
Duct leakage requirement in Milton
- Milton 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 Milton building department.
- From $350 for the first ducted system, often bundled with blower door testing and a full HERS rating.
What you can get back: 2026 Mass Save
- 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.
RESNET-certified · 15,000+ ratings completed · 5.0 stars across 135 Google reviews · (617) 501-6788
Duct Leakage Testing Milton MA
RESNET/HERS duct leakage testing in Milton — fast, precise CFM25 results your building department and energy-code file can rely on.
Duct Leakage Requirements in Milton
Milton 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 Milton, 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 Milton
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 Milton
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 Milton Home
Ductwork is the delivery system for every dollar of heating and cooling in a Milton home. If it leaks, that conditioned air is lost before it ever reaches a living space.
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 Milton 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 Milton
Best Fit for Projects Like
- Milton new-construction homes needing a duct test to complete the HERS rating
- Projects in Specialized-Code towns that must hit 3.0 CFM25 per 100 sq ft on all ducts
- Homes switching to a heat pump where duct tightness protects the new system's output
- Milton projects that need both envelope air-tightness and duct testing documented in one visit
- Heating and cooling alterations that add or extend ductwork in Milton
Duct Leakage Testing Milton MA Facts
- Because Specialized-Code towns test all ducts regardless of location, running ducts inside the thermal envelope is the surest way to pass.
- There are two testing points: a rough-in test before drywall and a post-construction test with the air handler installed, so leaks can be caught while they are still easy to reach.
- Ducts that leak about 20 percent of their conditioned air can force an HVAC system to work roughly 50 percent harder.
- A clean duct test protects the comfort and utility bills a homeowner will live with for decades.
Trusted for Duct Leakage Testing Milton 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 Milton MA FAQ
Get Started With Duct Leakage Testing Milton MA
Fast scheduling and permit-ready CFM25 reports for Milton and all of Norfolk County.
Call 617-501-6788HERS Ratings Across Milton and Nearby Communities
Home Energy Efficiency Consultants rates new homes, additions, and major renovations throughout Milton — including Milton Village, East Milton, Milton Center, and Blue Hills. Every Milton project is filed with the Town of Milton Building Department, 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 Milton, including Quincy, Braintree, Randolph, Canton, and Boston. Our Somerville office at 519 Broadway is the closest of our four Massachusetts locations — see our Somerville office or call (617) 501-6788 to get a Milton rating on the schedule.
Milton Specialized Energy Code — HERS Index Targets
Milton 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 Milton project up front so you know the exact target and the fastest path to hit it — call (617) 501-6788.
