Heating-load, furnace, heat-pump, boiler, garage, workshop and electric heater sizing calculators for preliminary HVAC planning. These tools provide screening estimates and do not replace ACCA load calculations, manufacturer selection data or qualified system design.
Garage heater size is the heat needed to offset wall, roof, door, window, and air-leakage losses at the desired indoor and outdoor design temperatures. Large garage doors and infiltration often matter more than floor area alone. How the garage heat-loss estimate works Opaque wall, ceiling, overhead-door, and window/personnel-door losses use U × A × ΔT….
Electric heater size should match the room’s design heat loss. Estimate heat loss in BTU/h, then convert useful resistance-heat output at 3,412 BTU/h per kilowatt. The result is a thermal requirement, not approval to connect that load to an existing receptacle or branch circuit. From heat loss to watts Electric resistance heat converts electrical energy…
Boiler sizing should begin with the building’s design heat loss. Compare that output requirement with the applicable boiler rating and manufacturer instructions. Do not select a boiler from connected radiation capacity alone and do not apply furnace airflow language to a hydronic or steam system. Building load comes before boiler rating The calculator estimates conductive…
A shop heater must replace envelope, roof, large-door, window, and infiltration heat losses at the required temperature rise. Workshops and metal buildings often have taller ceilings, larger doors, more outdoor-air exchange, and process loads than residential garages. Why this is not a garage-size shortcut The calculator asks for measured exterior perimeter, height, large-door area, construction…
The furnace size you need starts with the home’s design heat loss, not a universal BTU-per-square-foot number. Estimate the output BTU/h required to replace heat lost through the envelope and air leakage, then compare that load with a furnace’s output capacity. AFUE is used to relate approximate input BTU to useful output. Output BTU is…
This tool compares a screening heating load with the low-temperature capacity the user enters from manufacturer expanded performance data. It also shows a sensible cooling screen. The result is a capacity-gap check, not automatic heat-pump sizing, a tonnage recommendation, or a substitute for Manual J and Manual S. Why the controlling load changes by house…
Heating BTU needed is the design heat loss in BTU per hour. The estimate should reflect the room or building envelope, air leakage, indoor setpoint, and local outdoor design temperature. This page estimates that load; it does not select a furnace, boiler, heat pump, or electric circuit. A component estimate instead of BTU per square…