Free tool
HVAC load calculator
Four quick steps: location, construction, windows and systems. A designer reviews your answers and contacts you with accurate estimates.
Thanks
Someone from the team will contact you with accurate estimates.
Reach out during office hours and you’ll hear back within 30 minutes, whether it’s an email, text or call.
Why a designer, not a formula
A real ACCA Manual J works room by room, from your actual plans, window specifications and local design weather. That precision is why building departments require it, and why it often lands well below the rule of thumb. We use your answers to start that conversation, not to replace it.
Questions
Why don’t I see my numbers?
Accurate sizing needs a real ACCA Manual J from your plans. A LoadCalcs designer reviews what you entered and contacts you with accurate estimates, instead of a web formula guessing.
Can I submit this for a permit?
No. Building departments that follow the IRC require equipment sized with ACCA Manual S from ACCA Manual J room-by-room loads. We prepare that report.
What happens after I send it?
Reach out during office hours and you’ll hear back within 30 minutes, whether it’s an email, text or call. Send us your questionnaire and plans, and we’ll get you an estimate right away.
Does it calculate duct sizes?
No. Duct sizing needs room-by-room airflow from a Manual J. That is what Manual D is for, and Manual T is included with it.
Fast estimates
Ready for the real number?
Send us your questionnaire and plans, and we’ll get you an estimate right away. Reach out during office hours and you’ll hear back within 30 minutes, whether it’s an email, text or call.