CBE Thermal Comfort Tool — The Complete Guide: ASHRAE 55 Comfort Checks in Your Browser
CBE Thermal Comfort Tool is a thermal comfort calculator from the Center for the Built Environment at UC Berkeley. You enter air temperature, mean radiant temperature, air speed, humidity, clothing insulation and metabolic rate — and within seconds you see whether the point is comfortable under ASHRAE 55 or EN 16798.
CBE Thermal Comfort Tool
Center for the Built Environment, UC Berkeley
Thermal comfort calculation to ASHRAE 55 and EN 16798, in the browser.
Get it from the vendorWhat you get
- PMV and PPD — the classic comfort indices, with a flag showing whether the point is within the accepted range.
- Psychrometric chart — the comfort zone is drawn graphically and moves as you change inputs.
- Adaptive model — for naturally ventilated buildings.
- Local discomfort — draught and the ankle-to-head temperature difference.
- Ceiling fans — how far the design temperature can rise when air movement is added.
Why it matters to an HVAC engineer
Every degree added to the summer design point is an energy saving. The tool quickly shows whether 26 degrees with a fan can replace 24 degrees without a comfort penalty. It runs in the browser, with no installation and no registration, and its source code is open.
Related tools
For an annual energy simulation of the building — EnergyPlus and OpenStudio. For checking thermal bridges in the envelope — THERM.
EnergyPlus
US Department of Energy
Annual building energy simulation — envelope, HVAC, thermal comfort and daylight. The US DOE engine.
Get it from the vendorOpenStudio
National Renewable Energy Laboratory
Graphical workflow on top of EnergyPlus — geometry, systems and scenario comparison.
Get it from the vendor
THERM
Lawrence Berkeley National Laboratory
2D heat transfer analysis of envelope sections — thermal bridges, U-value and condensation checks.
Get it from the vendor
CONTAM
NIST
Airflow and contaminant dispersion inside buildings — ventilation, pressures, smoke and CO2.
Get it from the vendorThe bottom line
The fastest way to check whether a design point is genuinely comfortable — and to justify a higher setpoint with air movement.