Utility Calculator

Engineering tools for thermal, CHP, and utility calculations.

Primary Tool

Load Estimator

Rule-of-thumb heating and cooling estimate for early-stage screening. These defaults reflect a Philadelphia-style climate assumption and should not replace project-specific load calculations.

Heuristic workflow

Use this page to bracket a likely load range, not to finalize equipment selection. Confirm with Manual J, code-required calculations, or project-specific engineering before procurement.

Default multipliers reflect a mixed heating and cooling climate and should be tuned for your project when better data exists.
Heating load
60,000 BTU/hr
Heating MBH
60.0
Cooling load
40,000 BTU/hr
Cooling tons
3.33

Modeled load by scenario

The selected scenario uses your overrides. The other bars stay anchored to the default multipliers for comparison.

Typical gas appliance input ranges

Use these as context when your estimated load needs a reality check against common equipment sizes.

Residential furnace
40,000 - 120,000 BTU/hr

Typical AFUE residential furnace input range.

Unit heater
30,000 - 400,000 BTU/hr

Warehouse and garage suspended unit heater range.

Residential boiler
60,000 - 200,000 BTU/hr

Hydronic boiler input range.

Storage water heater
30,000 - 75,000 BTU/hr

Residential tank-style water heater.

Tankless water heater
150,000 - 199,000 BTU/hr

Typical condensing tankless unit.

Commercial water heater
199,000 - 1,500,000 BTU/hr

Restaurant and multi-use commercial service.

Commercial RTU gas heat
100,000 - 1,200,000 BTU/hr

Gas heat section within packaged HVAC units.

Commercial boiler (small)
500,000 - 2,000,000 BTU/hr

Schools and small commercial buildings.

Commercial boiler (medium)
2,000,000 - 10,000,000 BTU/hr

Hospitals and larger institutional plants.

Paint booth makeup air
1,000,000 - 5,000,000 BTU/hr

Representative paint booth makeup air heater range.

Industrial process heater
10,000,000 - 100,000,000 BTU/hr

Heavy industrial thermal process equipment.

Six-burner range
60,000 - 210,000 BTU/hr

Foodservice range, rough burner aggregation.

Commercial griddle
60,000 - 160,000 BTU/hr

Plate size and duty cycle drive the exact number.

Commercial fryer
80,000 - 200,000 BTU/hr

Representative single-vat fryer range.

Pizza oven
80,000 - 200,000 BTU/hr

Deck or stone oven depending on size.

CHP engine/turbine
1,000,000 - 10,000,000 BTU/hr

Thermal output band for packaged CHP systems.

Fuel cell CHP
300,000 - 6,000,000 BTU/hr

Thermal band for fuel-cell-based CHP systems.