How do I Find the BTU's of a Server?

In relation to my other article on Server Power Usage, I was asked about calculating the cooling needs of a server. One key value to know in this is that 1 Watt will produce 3.412 BTU per hour. This calculation takes the input volate (assumed at 120 volts for the US), and then the amperage load for a given server (router, etc.).

Server BTU Calculation
Enter The Input Voltage Volts
Enter The Amperage Load Amps
Calculated Results
Calculated BTUs BTUs

Cooling Needs

BTUs or British Thermal Units are heat measurements. Generally measured in per-hour increments. In common usage 12,000 BTU/h is considered a Ton. This is important because we cool and heat over time so we need to know how much cooling to throw in to the room per hour.

Now, the above calculation is simple in that it doesn't take into account fluctuating computing needs. You may say that you are only using 25% of your server's capacity and as such, reduce the BTU's generated and thus the cooling needed. Also, keep in mind other sources of heat, such as lighting, monitors, and other equipment.

Server BTU from Power Supply Size

Server BTU Calculation
Enter the Power Supply Wattage Watts
Calculated Results
Calculated BTUs BTUs

This alternative calculation gives you the maximum cooling needs assuming that you max out the power on a given power supply for a computer or server. For example:

For my server room we have

12500 watts of usage (that is max usage based on PS usage).

So 12,500 x 3.41 = 42,000 BTU/Hr.

One ton of capacity is 12,000 BTU/HR

so 42,000/12,000 == 3.5 Tons

So a 750 watt Power Supply generates 750 watts of heat. Now I do understand (my A/C guys didn't) that a 750 Watt PS rarely if ever uses any where near its max, that is going to best guess.

Based upon our wattage usage and room size, we needed a 3.5 ton A/C unit to cool it. I currently have a 1.5 ton unit and my server room is at a nice 87 degrees right now. We are putting in a 5 ton, hopefully next week.