12 min Manual J Load Calculation: Inputs, Steps and Who Does It
What goes into a Manual J load calculation, how to get one done for a permit, who can run it, how to read the report and the mistakes that send it back.
Guides · 3 guides
Load calcs
Understand HVAC loads and the inputs behind Manual J reports.
Heating and cooling loads for houses: what a Manual J asks for, which inputs move the result and how a block load differs from a room-by-room report a permit office reviews.
12 min 
11 min HVAC Estimating Software: 5 Checks for a Duct Takeoff
HVAC estimating software should trace every duct run, fitting and condenser line back to a sheet, an airflow and a dated load. Walk a worked six branch takeoff, see why per run rounding beats a blanket allowance, and get five checks for any tool.
11 min Manual J Calculator: Run a Room by Room Load in 5 Steps
A Manual J calculator turns areas, windows and design temperatures into heating and cooling loads. See the inputs, a worked two room report check, how block estimates differ from full reports, and why stacking safety factors backfires.