Built by working HVAC contractors

Free ACCA Manual J 8 load calculator + equipment sizing report

Generate residential heating and cooling load calculations using the ACCA Manual J 8 Abridged Edition (MJ8ae) method. Get a customer-ready PDF report you can use to size HVAC equipment, justify proposals, and qualify for IRA rebates — free, no signup required.

Start a free calculation Full workspace (save projects)

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Whole-house load calc

Block-load heating + cooling using the ACCA Manual J 8 Abridged Edition method. ACCA design temps for your jurisdiction, per-orientation glazing solar gain, infiltration model, internal gains. Real BTU/h numbers, not rule-of-thumb.

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Equipment recommendations

ACCA Manual S sizing. Furnace input + AC tonnage + heat-pump alternative with IRA rebate eligibility called out. No oversizing — we tell you the smallest standard size that meets the load.

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Customer-ready PDF

Professional report with project info, design conditions, load breakdown, equipment tiers, and a methodology section. Drop straight into your proposal package.

Honest about what this is. HVAC Design Studio implements the ACCA Manual J 8 Abridged Edition (MJ8ae) calculation method — same procedural shape as the Johnstone Supply MJ8ae spreadsheet used in HVAC trade training. It is not an ACCA-certified Manual J 8 product (that's a separate paid certification program). For permit submissions in code-strict jurisdictions, cross-check against an ACCA-approved tool. For commercial work that requires sealed mechanical drawings, pair with a licensed Professional Engineer.

Why we built this

Cheek Heating & Cooling LLC (Muncie, IN) was tired of paying per-report on the legacy tools and watching small-shop contractors skip load calcs entirely because the software was expensive or hard to learn. HVAC Design Studio is the contractor-built alternative: free for the load calc and PDF, focused on the workflow real HVAC techs actually run, and designed to scale into the deeper engineering tooling we use ourselves.