Two-way unit converters for temperature, airflow, water flow, pressure, energy, and power.
| Relationship | Conversion |
|---|---|
| 1 ton refrigeration | = 12,000 BTU/hr = 3.517 kW = 3,517 W |
| 1 MBH | = 1,000 BTU/hr = 0.2931 kW = 0.08333 tons |
| 1 HP (mechanical) | = 2,544 BTU/hr = 0.7457 kW = 745.7 W |
| 1 therm | = 100,000 BTU = 29.307 kWh = 8.33 ton-hr |
| 1 in. w.c. | = 249.1 Pa = 0.0361 psi = 0.0833 ft H₂O |
| 1 GPM water | = 500 BTU/hr per °F ΔT (sensible factor) |
| 1 CFM air (sensible) | = 1.08 BTU/hr per °F ΔT (sea level) |
| 1 CFM air (latent) | = 0.68 BTU/hr per gr/lb Δω (sea level) |
Doing this for a whole building? See this step inside a connected AIM Works project — loads, ventilation, equipment, and Design Review in one place.
Book a Demo →This is a live, bidirectional unit converter for the quantities that come up every day in mechanical design: temperature, airflow, water flow, pressure, energy, and power. Pick a category tab, type a value into any field, and every other field in that category updates instantly. There is no from/to selection to fiddle with.
It is built for moving between inch-pound and SI documentation — reading a European fan curve in Pa and m³/h, checking a chiller rating in kW against a US schedule in tons, or translating a pump duty from L/s to GPM — without hunting for conversion factors.
Each category converts through a single base unit. The tool divides your input by its factor to reach the base, then multiplies the base by every other unit’s factor. Temperature is the exception — it uses offset formulas rather than simple ratios.
| Temperature | °C = (°F − 32) × 5 ÷ 9 · K = °C + 273.15 · °R = °F + 459.67 |
| Flow base | 1 ft = 0.3048 m · 1 US gal = 3.785412 L → 1 CFM = 0.471947 L/s · 1 GPM = 0.0630902 L/s |
| Power base | 1 ton = 12,000 BTU/hr · 1 kW = 3,412.14 BTU/hr · 1 HP = 745.700 W = 2,544.43 BTU/hr |
| Pressure base | 1 in. w.c. = 249.089 Pa · 1 psi = 6,894.757 Pa · 1 ft H₂O = 12 in. w.c. |
| Energy base | 1 BTU = 1,055.056 J · 1 kWh = 3,412.14 BTU · 1 therm = 100,000 BTU |
Factors are the exact SI definitions or the NIST SP 811 values: the International Table BTU, the mechanical horsepower (550 ft·lbf/s), and the conventional inch of water (1,000 kg/m³ water under standard gravity). With 60 °F water an inch of water is 248.84 Pa, about 0.1% less. The field you type in is never rewritten; the others show seven significant figures.
Pressure converts unit-for-unit, so it works for pressure differences and for gauge pressures, but it does not add or remove atmospheric pressure (psig ↔ psia). The sensible factor 1.08 and latent factor 0.68 in the reference table above are sea-level air values and decrease at altitude as air density falls.
AIM Works brings peak loads, ASHRAE 62.1 ventilation, equipment and plant sizing, compliance checks, Design Review, and engineering deliverables into one connected mechanical design workspace.
Results are design estimates for preliminary sizing. Verify final designs against applicable codes and standards — engineering judgment and a licensed professional engineer’s review are required.