Question 1

What are Manual J, S and D?

Accepted Answer

Manual J is the ACCA heating & cooling load calculation; Manual S selects equipment to match those loads against manufacturer data; Manual D sizes and lays out the duct system to deliver the required airflow. Together they’re the standard HVAC design package.

Question 2

Block load or room-by-room?

Accepted Answer

A block load gives one number for the whole house; room-by-room gives a load for each room. Manual D duct design requires room-by-room loads, so every report we prepare is room-by-room.

Question 3

What do you need from me?

Accepted Answer

Your floor plan, the window and door schedule, building orientation, and insulation values (walls, ceiling, floor, windows). If some specs aren’t finalized, we can work from typical assemblies and adjust.

Question 4

Is it accepted by my permit office?

Accepted Answer

Manual J/S/D prepared to ACCA standards is the widely accepted basis for HVAC permit review in all states where applicable. If your office requests changes, we revise until it’s accepted.

Question 5

How is the J+S+D price decided?

Accepted Answer

By conditioned floor area, as a flat price agreed before we start: $395 up to 2,000 sqft, $485 from 2,001 to 3,500, and $585 from 3,501 to 5,000. J only is $295 / $385 / $485 and J+S is $345 / $435 / $535 across the same size bands. Above 5,000 sqft, or where a home has two or more HVAC systems, we quote the job. $485 is unchanged from the single flat price we charged before, so most homes pay exactly what they always did — smaller ones now pay less.

Question 6

Why did the price change in 2026?

Accepted Answer

Earlier in 2026 the flat price moved from $350 to $485. On 1 April 2026 Wrightsoft consolidated Right-Suite into a single Residential subscription and retired the tier we had been licensed on, at a significantly higher annual cost, and Right-Suite is the software every report here is produced in. Scope, the 5 business-day turnaround and free revisions until your permit office accepts the report are all unchanged.

Question 7

Do you handle commercial buildings?

Accepted Answer

Yes — commercial cooling and heating loads are calculated in Carrier HAP using the ASHRAE heat balance method, for offices, retail, restaurants, warehouses, tenant fit-outs and multi-system buildings. Every commercial project is scoped and quoted individually: send your plans and you get a flat, all-in quote before any work begins. No hourly billing. Turnaround is 1–2 weeks.

Question 8

Can you do it faster?

Accepted Answer

Yes. Add the 48-hour rush on the order form and your draft arrives within 48 hours of complete plans, for +$99 on any tier.

Question 9

Does my Manual J need a PE stamp?

Accepted Answer

Usually not. The IRC (M1401.3) requires the load calculation and equipment sizing but names no signatory, and ACCA only requires approved software. Our reports are produced in Wrightsoft Right-Suite, ACCA-approved “Powered by Manual J” software, so they meet that requirement exactly as delivered, without a seal. In most states the licensed HVAC contractor, the builder or the designer who prepares the drawing set submits the report with the permit, and we sign it as preparer. Where your drawings need a seal, the engineer or architect who seals them can seal our report too, at no extra cost from us. Known exceptions: New York City and much of New York State (mechanical submittals signed and sealed by a registered design professional), New Jersey (a design professional, or the HVACR contractor on smaller buildings), North Carolina (the state board requires the load calculation to be run by the licensed HVAC contractor or an NC-licensed PE, so our report serves as the contractor’s working document unless sealed), and some Florida counties (submitted by the licensed air-conditioning contractor or a Florida PE). California uses Title 24 CF1R forms, with Manual J as the supporting calculation. Confirm with your permit office before ordering; tell us the jurisdiction and we’ll check too.

Question 10

Can you stamp it for me?

Accepted Answer

Yes, as an optional add-on on the order form: +$149 for a seal by a partner engineer licensed in your project’s state, added to the amount held at checkout. The sealed copy follows the draft by about 2 business days. We recommend it only when your permit office requires a seal and nobody on your project holds a licence there — it is not something we require. If no partner engineer is available for your state, we tell you before work starts and remove the add-on from your order.

Question 11

I don’t have insulation values or a window schedule.

Accepted Answer

We use code-minimum values for your climate zone and list every assumption in the report. Send better data at any time and we update it.

Question 12

Can you work from a hand sketch?

Accepted Answer

Yes, if it is dimensioned and shows window sizes and orientation. Photos on their own are not enough.

Question 13

ADUs, additions and remodels?

Accepted Answer

Yes — same tiers, priced by the conditioned area of the new or affected space.

Question 14

Do you prepare CSA F280 heat-loss calculations for Canadian permits, and who signs them?

Accepted Answer

Yes, we prepare CSA F280 heat-loss and heat-gain calculations for Canadian projects. In Ontario, permit submissions must be signed by a BCIN-qualified designer, so your BCIN designer or contractor reviews and signs our calculation.

Question 15

Does the load calculation include mechanical ventilation (ERV/HRV) requirements?

Accepted Answer

Yes. The whole-house mechanical ventilation calculation (ASHRAE 62.2 / IRC M1505) is included in every Manual J package at no extra charge.

Question 16

If the equipment model changes after the report, will you update Manual S?

Accepted Answer

The first equipment-model change after delivery is free: we update the Manual S for the new model. Each later change is $49.

Question 17

Does the direction the house faces change the load, and how are multi-orientation builder plans handled?

Accepted Answer

Each orientation is a separate report, because a house facing a different direction can have a different cooling load. Builders ordering several orientations or plans get a volume discount.

Question 18

When do I pay?

Accepted Answer

When you order, you enter your card on Stripe’s secure checkout and the price is put on hold — nothing is charged yet. We charge the card when your draft is delivered. Card holds last 7 days, so if a draft ever runs past day 6 we charge it then. If we can’t deliver, the hold is released and you pay nothing. Commercial and other quoted work is different: nothing is charged until you accept the quote.

Question 19

How are my plans handled?

Accepted Answer

Your files are used only to prepare your report. We don’t publish or share them.

Question 20

Is a Manual J required for my HVAC or building permit?

Accepted Answer

The International Residential Code (M1401.3) and the IECC require heating and cooling equipment to be sized using ACCA Manual J (loads) and Manual S (equipment selection). Whether your building department asks to see the calculation varies. Many require it for new homes and additions, and a growing number also ask for it on equipment replacements. Check your permit checklist, or send it to us and we’ll tell you what’s needed.

Question 21

Is a Manual J the same as a ‘heat load calculation’ the permit office asks for?

Accepted Answer

Usually, yes. For homes, ‘heat load calculation’, ‘load calc’ and ‘heat gain/heat loss calculation’ all refer to an ACCA Manual J. Some offices want the full room-by-room report rather than a one-page summary. Every report we prepare is room-by-room, so it meets either request.

Question 22

Do I need a Manual J to replace an existing AC, furnace or heat pump?

Accepted Answer

It depends on your city. Many require a Manual J for change-outs, especially when the equipment size or system type changes, such as switching from a furnace to a heat pump. Even when it isn’t required, it’s worth doing: it often shows the old unit was oversized, so you can buy a smaller system and save on both purchase and running costs.

Question 23

Why can’t HVAC be sized by square footage (for example, ‘one ton per 500 sq ft’)?

Accepted Answer

Two 2,000 sq ft homes can need very different systems, depending on climate, window area and orientation, insulation levels, air tightness and duct location. Rules of thumb such as ‘one ton per 500 sq ft’ were made for older, leakier houses and usually oversize modern homes. Manual J calculates the actual load of every room.

Question 24

What goes wrong if my HVAC system is oversized?

Accepted Answer

An oversized system causes four problems. It short-cycles, turning on and off too often. It removes too little humidity, leaving rooms clammy and raising the risk of mold. Rooms end up at uneven temperatures. And it costs more to buy and run, and wears out sooner.

Question 25

Why is my Manual J result smaller than the system I have now?

Accepted Answer

This is common, and the calculation is usually right. Older systems were often sized by rule of thumb, and many homes have since gained new windows, insulation or air sealing. If your current system short-cycles or the house feels clammy in summer, that’s a sign it’s oversized. Our report lists every assumption, so you or your contractor can check each one.

Question 26

How do you size a heat pump for a cold climate, and how is backup heat handled?

Accepted Answer

We size the heat pump to the cooling load within Manual S limits. We then check its heating capacity at your outdoor design temperature using the manufacturer’s performance data. Any shortfall is covered by backup heat, either electric strips or a gas furnace (dual fuel), sized to make up the gap. Modern cold-climate heat pumps often need little or no backup.

Question 27

How are ductless mini-splits sized room by room, and how do you avoid short-cycling?

Accepted Answer

Each indoor head is matched to its own room’s Manual J load instead of being oversized. We prefer variable-speed systems that can turn down well at low load. We also avoid connecting too many small heads to one outdoor unit, which is the main cause of short-cycling and humidity problems with ductless systems.

Question 28

Which outdoor design temperatures do you use for my location?

Accepted Answer

We use the ACCA Manual J Table 1A design conditions (99% heating and 1% cooling) for the nearest weather station. If your jurisdiction publishes its own design temperatures, we use those instead. Inflated design temperatures are one of the most common reasons plan reviewers reject a Manual J.

Question 29

How much larger than the calculated load can my equipment be under Manual S?

Accepted Answer

Manual S sets limits on how far equipment can exceed the calculated load. Typically, air conditioners and heat pumps must deliver 90–115% of the total cooling load, while still covering the sensible load. Heat pumps in heating-dominated climates may go up to about 125%. Furnaces must deliver 100–140% of the heating load. We select specific models from AHRI and manufacturer data that fall inside these limits.

Question 30

What is Manual T (air distribution / register selection)?

Accepted Answer

ACCA Manual T covers air distribution: choosing the supply registers, diffusers and return grilles, including their size, throw and placement, so air reaches every part of the room evenly and quietly. It is available with our Manual D on request.

Question 31

What are the most common reasons a Manual J gets rejected at plan review?

Accepted Answer

The five most common reasons are: inflated outdoor design temperatures; wrong insulation, window or infiltration values; a block load submitted where room-by-room loads are required; equipment outside Manual S limits; and missing ventilation or duct design where the jurisdiction requires them. We check all five before delivery.

Question 32

Can a homeowner order a Manual J to check a contractor’s proposed system size?

Accepted Answer

Yes, and we encourage it. Send us your plans or a dimensioned sketch along with the contractor’s proposed system. We’ll tell you whether the size is right and what to ask your contractor if it isn’t. It costs the same as a standard Manual J.

Question 33

In California, is a Manual J still needed alongside Title 24?

Accepted Answer

Yes. California’s energy code (Title 24, Part 6) requires heating and cooling loads to be calculated with ACCA Manual J or an equivalent method. This is separate from the CF1R energy compliance documents, and many California cities ask for the load calculation with the mechanical permit. We prepare the Manual J/S/D; residential Title 24 compliance documents are not offered at this time.

Question 34

Can I bundle a Manual J with a REScheck?

Accepted Answer

Need a REScheck too? Order it with your Manual J/S/D and save $50. REScheck reports are available from our sister site getrescheck.com.

Deliverable	Cool	Heat	Detail
Manual J — room loads	28.4	41.2	12 rms
Manual S — equipment	2.5 t	44k	AHRI
Manual D — ducts	0.10	—	18 runs

Room	Area	Cool	Heat
Living / Kitchen	520	8.1	10.4
Primary Bed	240	3.6	5.2
Bed 2 / 3	300	4.2	6.9
Bonus	280	4.0	6.1

State	Homes & ADUs	Multi-family & mixed-use	Office & commercial	Retail, food & hotels	Health, education & labs	Industrial & other	Projects
California	48	15	45	31	9	8	156
Texas	23	12	13	12	8	7	79
Florida	13	9	9				42
New York		13					15
Georgia							12
Colorado							9
Maryland							7
Pennsylvania							7
Washington							6
Michigan							5
New Jersey							5
Ohio							5
Massachusetts							4
Arizona							3
Connecticut							3
Missouri							3
New Mexico							2
North Carolina							2
South Carolina							2
Virginia							2
Alabama							1
Arkansas							1
Illinois							1
Indiana							1
Nevada							1
Tennessee							1
U.S. Virgin Islands							1
Utah							1
Washington DC							1
Wyoming							1

Manual J, S & D. from $395, delivered in 5 business days.

See a sample before you order

What you get — the J / S / D stack

Manual J — loads

Manual S — equipment

Manual D — ducts

Choose your scope

Load calculation

Loads + equipment

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Commercial buildings

Cooling & heating loads in Carrier HAP

Quoted to your project

Block load vs room-by-room

One load for the whole house

A load for every room

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Your project details

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What clients say

Where our team has delivered

Where we have delivered

What we have delivered, where

Our guarantee & common questions

Basics

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Sizing

Manual S / D / T

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