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HVAC Load
HVAC load calculator: BTU/h, tons, ducts and a PDF
About HVAC Load
HVAC Load sizes heating and cooling systems for US houses. Enter floor area, ZIP code and year built to get heating and cooling BTU/h and tons. See where the load comes from, get CFM and a duct size per room, and check if the unit you plan to quote fits. For a heat pump, see the balance point and backup heat. Make a two page PDF report with your logo. The web app is free, needs no account and works with no signal after the first visit. Estimates in the style of ACCA Manual J, not affiliated with ACCA.
- Who it is for
- HVAC contractors, installers, estimators and service techs who size heating and cooling for US houses
- Problem it solves
- Sizing a system by rule of thumb often leads to an oversized or undersized unit, and a proper load calculation takes time on a service call.
- The solution
- Enter floor area, ZIP code and year built to get heating and cooling BTU/h and tons, then go deeper with a load breakdown, room by room CFM and duct sizes, an equipment check and a PDF report.
- What makes it unique
- Free web app with no account and no limit on jobs. The math runs on your device, so it works with no signal in an attic or crawl space after the first visit. Estimates in the style of ACCA Manual J, not affiliated with ACCA.
Features
Heating and cooling load
BTU/h and size in tons from area, ZIP and year built
Load breakdown
What-if list of fixes and BTU/h saved
Room by room
Heat, cool, CFM and round duct size, or duc
Equipment check
AC, furnace and heat pump, with balance point and backup heat
Two page PDF report
With your logo and client details
Details
- Platforms
- Web
- Pricing
- Free
- Built for
HVAC contractors, installers, estimators and service techs who size heating and cooling for US houses
- Building since
2026
Technology
HVAC Load screenshot showing information about a hvac load
1 / 4Website performance
Recorded mobile lab measurements and finalized weekly standings from IndieTools Speed.
100ExcellentMobile Lighthouse
Measured · UTC
- Load time
- 486 ms
- FCP
- 946 ms
- LCP
- 946 ms
- CLS
- 0.000
- TTFB
- 9 ms
- TBT
- 0 ms
- Speed index
- 1.04 s
These stored lab observations describe controlled test runs. They are not real-user Core Web Vitals or a guarantee of search rankings. Weekly standings below remain attached to their finalized edition.
- Overall rank
- Not finalized
- Best overall rank
- Not finalized
- 0 top 10 finishes
- Best category rank
- Not finalized
- 0 category wins
- Latest change
- 65 ms faster
- No finalized score yet
Method: psi-mobile-two-sample-mean-v1 · 2 samples per reading. Only readings with the same recorded method and sample count share a chart. Lab results can vary between runs.
Website performance history
Inspect every successful mobile Lighthouse lab measurement by metric and date range.
Range
Metric
Latest score
100 / 100
Higher is better
3 measurements
Use the left and right arrow keys to inspect measurements. Use Home or End to jump to the first or last measurement. Press Escape to dismiss the chart tooltip.
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