Heating & cooling, simulated room by room
A transient physics model: each room is an occupant-level air layer, a ceiling air layer, and the thermal mass of its surfaces. Watch the indoor temperature track (or lose) the thermostat as the weather swings — and see why a radiator, a forced-air furnace, a heat pump and a ceiling fan feel so different even when they move the same heat.
Air stratification — floor vs. ceiling
Each bar is one room's air column at the playhead. A tall temperature gap = stratified (warm air stranded at the ceiling). Forced-air registers and weak mixing stratify; a ceiling fan or radiant floor evens it out.
Effectiveness — over the full run
“Comfort” = share of time the occupant operative temperature (air + radiant) sat within ±1.5 °C of setpoint. “min/kWh” is comfortable minutes per kWh of all energy in — the head-to-head efficiency of the delivery method.