Server Room Cooling Calculator

Work out the cooling a server room needs from its IT heat load, in BTU per hour and tons of refrigeration, with an overhead allowance. Calculates in your browser.

Required cooling

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In BTU/hr-
In kW (thermal)-
Total heat load-

Show the math

Almost all the power a server draws becomes heat, converted from watts to BTU per hour and tons:

BTU/hr = watts × 3.412 · 1 ton = 12,000 BTU/hr

The overhead allowance pads the IT load for people, lighting and a safety margin. Size cooling with redundancy (N+1) so a unit can fail or be serviced without overheating the room. Calculated entirely in your browser.

What this does

A server-room cooling calculator works out the cooling needed from the IT heat load, in BTU per hour and tons of refrigeration.

How to use it

  1. Enter the IT load in watts.
  2. Add an overhead allowance.
  3. Read BTU/hr and tons of cooling.

How it works

Almost all power drawn becomes heat, so the cooling load roughly equals the IT load. Overhead pads for people, lighting and a safety margin.

BTU/hr = watts × 3.412; tons = BTU/hr ÷ 12,000

Understanding your result

Because nearly all the power a room draws turns into heat, the cooling load roughly equals the IT load, which is the headline takeaway. The overhead allowance covers people, lighting, and a safety margin, and you should also plan for redundancy, since a cooling failure can overheat a room within minutes, far faster than most expect.

Example

A 5 kW IT load needs about 17,000 BTU/hr, or roughly 1.4 tons, before overhead.

Sources & methodology

Last updated .

Frequently asked questions

How much cooling does a server room need?

Almost all the electrical power equipment draws becomes heat, so the cooling load in watts roughly equals the IT load. Convert to BTU per hour by multiplying watts by 3.412, and to tons by dividing BTU/hr by 12,000.

What is the overhead allowance for?

It pads the IT load for heat from people, lighting and a safety margin. A common starting point is around 20%, but adjust it for your room.

Should I add redundancy?

Yes. Size cooling with redundancy (N+1) so a unit can fail or be serviced without the room overheating.