Manual J, S and D Calculations for Building Permits in Massachusetts
Massachusetts building departments can ask for a Manual J heating and cooling load calculation and a Manual S equipment selection report with a new home or addition permit (energy code section R403.7), and duct systems are designed to Manual D under the residential code. Home Energy Efficiency Consultants prepares Manual J, S and D reports for permits, sized for heat pumps and matched to your HERS rating model, so the equipment, the ducts and the energy report all agree.
What you get
Room-by-room Manual J loads, a Manual S equipment selection matched to real heat pump performance, and a Manual D duct layout with sizes, delivered with your projected HERS report.
What Manual J, S and D Are
| Report | What it does | Why the inspector cares |
|---|---|---|
| Manual J | Room-by-room heating and cooling load calculation from the plans: insulation, windows, air leakage, orientation and Massachusetts design temperatures | Proves the house is designed around real loads, not a rule of thumb |
| Manual S | Picks equipment that actually meets those loads, using the manufacturer's performance data (heat pump capacity at cold temperatures) | Stops oversized or undersized systems; required with Manual J under R403.7 |
| Manual D | Duct design: duct sizes, trunk and branch layout and airflow to each room | Ducts sized right deliver the airflow Manual J calls for and help pass the duct leakage test |
When Massachusetts Asks for Them
- Energy code R403.7: heating and cooling equipment is sized with ACCA Manual S based on Manual J loads. The Mass Save residential permit and plan review checklist lists "Heating and cooling load calculations (Manual J) and Equipment Selection report (Manual S) to be submitted (R403.7)".
- Residential code: the Massachusetts Residential Code adopts the 2021 IRC, which sizes equipment with Manual S and J (M1401.3) and designs duct systems with Manual D (M1601.1).
- Town checklists: some towns spell it out. Reading asks for Manual J and S when there is new ductwork or a mini-split, and Manual J, S and D for a new home.
- Heat pumps and HERS: right-sized heat pumps run better, cost less and help hit the HERS 42/45 targets in Stretch and Specialized towns.
How It Works
Send plans and specs
Floor plans, elevations, window specs, insulation and the heat pump or system you are considering.
One building model
We model the house once for the HERS rating and the load calculation, so the numbers match.
Permit-ready reports
Manual J loads, Manual S equipment selection and Manual D duct sizes, ready to upload with your permit.
Equipment check
If the system on the plans is oversized or short on cold-weather capacity, we flag it before it is ordered.
Duct leakage test
At rough-in or final we test the ducts against the code limit of 4.0 CFM25 per 100 sq ft.
Confirmed HERS
The confirmed HERS certificate closes out the energy side of the permit.
Pair It With Your Energy Code Report
Most projects that need Manual J also need a stretch code report (projected HERS rating). Doing both from one model saves time and keeps the permit package consistent. See the new home permit checklist and the addition permit guide for the rest of the paperwork.
What a Manual J Measures
Done in ACCA-approved load calculation software, room by room.
Inputs
- Winter heat loss and summer heat gain (BTU/h) for every room
- Insulation levels in walls, roof and floors
- Window area, U-factor, SHGC and orientation
- ACCA design temperatures for your town
- Air tightness and duct location and tightness
- Occupants, appliances and ventilation (ERV/HRV) loads
How to get started
- Send your plans and the equipment you are considering.
- We deliver Manual J, S and D in 6–12 business hours.
- Your HVAC contractor files them with the permit. For Mass Save heat pump rebates, use an installer in the Mass Save Heat Pump Installer Network so the sizing paperwork is submitted correctly.
- At final, we test the house (blower door, ducts, ventilation) for your HERS rating.
How Manual J and Your HERS Rating Work Together
One set of numbers for the whole house, so the loads are accurate and plan review sees no conflicts.
A Manual J is only as accurate as its inputs. Most online calculations guess at insulation, window ratings and how leaky the house is. We build the Manual J from the same energy model we use for your HERS rating, then confirm the key assumptions with real tests at final.
| Input | HERS rating | Manual J / S / D |
|---|---|---|
| Walls, roof, windows | Insulation R-values, window U-factor and SHGC from your plans | The same specs go into the room-by-room heat loss and gain |
| Air tightness | Target ACH50, then measured with a blower door at final | We use that target instead of a generic "average house" leakage guess, which is a main cause of oversized systems |
| Ducts | Duct location and leakage, then tested at final | Ducts inside the conditioned space carry far less load than ducts in an attic |
| Ventilation | The ERV/HRV airflow required by code | The ventilation load is included, with the ERV’s heat recovery counted |
| Equipment | The heat pump’s efficiency rating drives the HERS score | Manual S picks the same unit, so the HERS report and the HVAC submittal match |
- Right-sized equipment: accurate loads mean the heat pump is not oversized, so it runs longer, dehumidifies better and costs less.
- Verified at final: the blower door and duct leakage tests check the air-tightness and duct assumptions the Manual J was built on.
- No mismatched paperwork: the energy code requires heating and cooling sized per ACCA Manual J and S (R403.7). When the HERS report and the Manual J/S come from the same model, the equipment, efficiencies and loads agree.
- Mass Save ready: the heating load at design temperature is what Mass Save checks the 90–120% sizing against.
Manual J, S & D Pricing and Turnaround
Real, accurate local calculations, not a cheap online template.
| Service (one home) | Price |
|---|---|
| Manual J: room-by-room heating and cooling loads | $250 |
| Manual J + S: loads and equipment selection | $400 |
| Manual J, S & D: loads, equipment and duct design | $600 |
| Manual D only (J already done by others) | $250 |
| With your HERS rating from us | $25 off J, S & D |
| Turnaround | 6–12 business hours once we have complete plans |
Volume pricing for builders and HVAC contractors
| Homes per year | Manual J | Manual J + S | Manual J, S & D |
|---|---|---|---|
| 1–9 | $250 | $400 | $600 |
| 10–49 | $225 | $360 | $540 |
| 50+ | Quote | Quote | Quote |
- Done by our local Massachusetts team, a RESNET-certified HERS rating company, not an anonymous online calculator.
- Built from your actual plans: real wall, window, insulation and air-tightness specs and the correct ACCA design temperatures for your town.
- Room-by-room loads included, no extra charge.
- Matched to your HERS energy model, so the loads, equipment and energy report agree at plan review.
- Permit-ready reports, and we answer the inspector’s questions.
- Sized for Mass Save heat pump rules (90–120% of the heating load at design temperature).
Homes over 5,000 sq ft, more than 2 HVAC systems and multifamily are quoted. Send your plans or call 617-501-6788.
FAQ
How much does a Manual J cost?
Manual J is $250, Manual J and S are $400, and Manual J, S and D are $600, with $25 off when we also do your HERS rating. Turnaround is 6–12 business hours once we have complete plans. Every calculation is done by our local Massachusetts team from your actual plans, with room-by-room loads included.
Is a Manual J required for a building permit in Massachusetts?
The energy code (R403.7) sizes heating and cooling equipment with Manual S based on Manual J loads, and the Mass Save permit checklist lists Manual J and Manual S as items to submit. Many building departments ask for them on new homes and additions, and some, like Reading, list them on their permit checklist.
What is the difference between Manual J, S and D?
Manual J calculates the heating and cooling load room by room. Manual S selects equipment that meets that load using the manufacturer's data. Manual D designs and sizes the ducts to deliver the airflow each room needs.
Do mini-splits and ductless heat pumps need a Manual J?
Equipment sizing still applies. Reading, for example, asks for Manual J for mini-splits and existing systems, and Manual J and S when there is new ductwork.
Can you do the Manual J and the HERS rating together?
Yes. We build one model of the house for both, so the loads, the equipment and the HERS report agree.
How do I order Manual J, S and D reports?
Email your plans to Energyconsultants01@gmail.com or call 617-501-6788. We quote the same day.
Town-by-Town Permit Checklists
Local building department details, checked on each town's own website:
Sources: Mass Save residential energy code permit checklist (PDF) · Reading residential permit checklist (PDF) · 780 CMR 10th Edition. Code text current as of October 2026; DOER has proposed updates to the Stretch and Specialized codes, so confirm before you file.
Related: Stretch code report for permitting · What triggers a HERS rating · REScheck and COMcheck · Phius verification
Need Manual J, S and D for Your Permit?
Send your plans today. Most projected HERS reports are ready in about one business day after the quote is accepted.
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