US · ACCA Manual J 8th Edition
Run a real Manual J at the kitchen table.
Not back at the office. Eight inputs gets you a ballpark. Sixteen gets full MJ8 accuracy with equipment sizes and a branded PDF the homeowner can actually read.
- iPhone & iPad
- Works offline
- Free trial: 2 calcs + 2 PDFs
- iCloud sync
Who it’s for
For the contractor who knows the rule of thumb costs money.
Residential HVAC contractors and comfort advisors quoting replacements. You know the 400-square-feet-per-ton guess causes callbacks and oversized equipment. This app does the actual load math on site, then hands the homeowner a report with your logo on it. Works in the basement with zero bars.
- Three levels of calc. Simple is 8 inputs for a quick estimate. Moderate is 15 inputs, within 10 to 15 percent of full Manual J. Pro is 16 inputs plus overrides for 5 to 10 percent accuracy.
- Real MJ8 math. ACCA Manual J 8th Edition methods: F-factor slab losses, LBL N-factor infiltration, solar gain by window orientation, roof color, duct loss factors.
- Equipment sizing built in. Manual S guidance shows the AC tonnages, furnace sizes, and heat pump sizes that actually fit the load, with oversize warnings and heat pump balance point.
- Climate data by ZIP. ASHRAE 99 percent heating and 1 percent cooling design temps, pulled from your ZIP or GPS. All bundled in the app. No signal needed.
- Beats the rule of thumb, and shows it. The results screen compares your calc against 400 square feet per ton, so the homeowner sees why the smaller unit is the right unit.
- A report that sells. One tap generates a Home Comfort Assessment PDF with your logo and contact info, the load breakdown, MJ8 technical details, and up to 20 tagged site photos.
- Field-proof. Offline first. Auto-saves every project. Syncs across your iPhone and iPad through iCloud.
- Try it free. Two full calculations and two PDF exports before the Pro subscription kicks in.
In the field
From front door to signed report in one visit.
The numbers behind the numbers
Math you can defend to an inspector.
- Design temperatures: sourced from ASHRAE Fundamentals and the Energy Star County Level Design Temperature Reference Guide, with full-ZIP mapping plus a ZIP3 fallback for national coverage, including climate zone and MJ8 daily range.
- Manual S limits enforced: cooling capacity capped at 115 percent of load, heating at 140 percent, with oversize warnings when a size busts the limit.
- Heat pump guidance: capacity at 47°F and 17°F plus a calculated balance point.
- Metric option: SI units toggle and an international location mode for jobs outside US ZIP coverage.
- PDF report sections: Property Details, Load Calculation Breakdown, Manual J 8th Edition Calculation Details, Detailed Inputs (Pro mode), and Site Assessment Photos.
Get it
Two free calcs. See if it earns a spot on your home screen.