Heating loss estimator
See the heat loss behind the inputs.
Compare steady-state heating losses through the exterior surfaces and outdoor airflow you enter. Review each component in BTU/h and kW.
A component estimate for planning. This is not a Manual J calculation, a cooling-load model or an equipment-size recommendation.
Use it free and without an account. The tool stands on its own: it is not a feature of a paid plan, and you can use it whether or not you use OrdexisOne.
The calculation
Follow each part of the result.
For each entered surface, heat loss is its area × assembly U-value × indoor–outdoor temperature difference. The surface losses are added to the sensible heat needed for the entered outdoor airflow.
Surface loss = A × U × ΔT
Outdoor-air loss = 1.08 × CFM × ΔT
The imperial airflow factor uses air density of 0.075 lb/ft³ and specific heat of 0.24 BTU/(lb·°F). It is an approximation for air near room temperature at sea level; altitude and air conditions affect it. Metric inputs are converted consistently before calculation.
Use a complete load calculation for design.
Cooling needs solar, internal and moisture loads that this tool does not model. A complete heating design also needs all relevant envelope, ventilation and distribution effects, followed by equipment selection.
Use assessed inputs and the appropriate professional design procedure before selecting or installing a system.
Connect the assessed work to your operation.
Explore service intake, assessed options, assigned technician visits and continuing HVAC maintenance in OrdexisOne.
Other free tools: turn the room into airflow, duct area and velocity, work out voltage drop on a circuit run, estimate the labor rate the work needs, or see every free tool.