Skip to content
LoadCalcStack

Standards

What is Manual J and ACCA-approved load-calc software?

Plain-language primer on ACCA Manual J residential load calculations and why contractors check ACCA's approved software list. No invented stats.

Updated 2026-09-15. Author: LoadCalcStack editorial team. No ranked winner.

Manual J is ACCA’s residential heating and cooling load calculation standard. LoadCalcStack covers software used to run those calculations for HVAC contractors. This site does not rank a winner.

What Manual J is (and is not)

Manual J estimates how much heating and cooling a home needs so equipment can be sized appropriately. Related ACCA manuals often discussed with load software include Manual S (equipment selection) and Manual D (duct design). LoadCalcStack is a software directory brand; Manual J is ACCA’s standard, not our product name.

Why “ACCA-approved software” matters

Many jurisdictions and programs expect Manual J procedures. ACCA publishes an approved software list so contractors and code officials can check which products ACCA has recognized. Always verify the live list at ACCA approved software rather than relying only on a directory page.

How LoadCalcStack uses this

We link the ACCA list as authority, cite retrieval dates on vendor prices, and note when a vendor does not publish a price — you request a quote instead.

Sources

Related vendor profiles