Walk-In Cooler Calculator

Spec the walk-in condensing unit.

Spec a walk-in cooler condensing unit using ASHRAE-style heat-load math: surface conduction, air infiltration, and product load — with a 25% safety factor on top. Sized in BTU/hr at the design temperature you enter.

⏱ ~45 sec•ASHRAE-style heat-load math•Commercial

+25%

Safety factor

ASHRAE

R-25

Cooler insulation

Min

R-30

Freezer insulation

Below 32°F

1.08

Air infiltration

BTU/cf/°F/ACH

STEP 01

Box dimensions,
temps, traffic.

Dimensions in feet. Temperatures in °F. Traffic determines air changes per hour.

Length (ft)

Width (ft)

Height (ft)

Target temp (°F)

Ambient (°F)

Door traffic

Restaurant line is high; back-of-house storage is low.

Updates live as you type

Required cooling capacity

Updated live

110,720BTU/hr

2+ HP condensing unit (24,000+ BTU/hr)

Interior volume

640 cu ft

Insulation

R-20

Power requirement

136 A @ 240V (~33 kW)

Under the hood

ASHRAE-style heat-load with safety margin.

Three load components: surface conduction through walls, air infiltration on door open, and product load from stored items. 25% safety factor on top.

01
Surface conduction
Total surface area × (ambient − target) × 1.5 heat-transfer factor (assumes R-25 insulation).
02
Air infiltration
Volume × ACH × 1.08 × ΔT. ACH = 1 (low traffic), 2 (medium), 4 (high traffic).
03
Product load
Approximated as 10 BTU/hr per cubic foot of interior volume — typical for stored prepped food.
04
Safety factor
Sum × 1.25 for door opening losses, defrost recovery, hot product loading, and equipment aging.

Questions

Frequently asked

It depends on volume, target temperature, ambient temperature, and how often the door opens. A typical 10×8×8 ft cooler at 35°F in a 75°F room needs roughly 8,000–14,000 BTU/hr — but always size with the actual heat-load calc.