Server Room Cooling

Servers, network switches and storage give off heat around the clock. In a small, closed room, the temperature can climb quickly, and equipment that runs too hot can slow down, shut down or fail early. A properly designed cooling system keeps the room within a safe range all year, day and night.

Our team designs and installs cooling for server rooms, comms rooms and IT cupboards. For the rest of your premises, see our guide to commercial air conditioning.

What Temperature Should a Server Room Be?

Industry guidance from ASHRAE recommends keeping the air entering IT equipment between 18°C and 27°C. The temperature that matters is at the front of the racks, where the equipment draws air in, not the average for the room.

Humidity matters too. Very dry air raises the risk of static, and very humid air raises the risk of condensation, so the room should stay within the equipment's limits.

Why an Office System Is Not Enough

• It runs all year. A server room needs cooling in winter as well as summer, so the system must be able to cool when it is cold outside. Not every system designed for comfort cooling can.

• It runs day and night. The cooling has to keep up continuously, not just during office hours.

• It needs its own control. If the server room shares a system with the office, it can lose cooling when the office is switched off or set to heating.

Sizing for the Heat

Nearly all the electricity used by IT equipment ends up as heat in the room. So the starting point for sizing is the power drawn by the equipment, plus heat from lighting, people and the sun on outside walls. We also allow for equipment you plan to add.

Backup Cooling

If the only cooling unit fails, the room can overheat quickly. Many server rooms have two units, arranged so that one can take over if the other fails. They can be set to take turns, which spreads the wear between them.

Monitoring and Alarms

A temperature sensor and alarm warn you if the room starts to overheat, so you can act before equipment is affected. Monitoring systems can send alerts by email or text, or connect to a building management system.

Positioning and Airflow

• Position indoor units so cool air reaches the front of the racks and warm air returns to the unit.

• Keep pipework and condensate drains away from the racks, so a leak cannot drip onto equipment.

• Keep the room closed. Doors propped open and gaps in the ceiling let warm air in.

• Where possible, arrange racks so the fronts face each other and the backs face each other. This keeps cool and warm air apart.

Maintenance

A server room system works harder than most, so regular servicing matters. We recommend at least one service a year, and the filters may need cleaning more often. Larger systems also need F-gas leak checks by law, as our guide to commercial air conditioning explains. See our air conditioning servicing page.

Frequently Asked Questions

Can I just use a portable air conditioner?

It is not a reliable long-term answer. A portable unit is noisy, less efficient and usually needs a hose through a window, and there is no backup if it fails. See do portable air conditioners work?

Does a comms cupboard need cooling?

If it holds network or server equipment and gets warm, yes. Even a small cupboard can overheat when it is closed with no airflow.

Can the office air conditioning cool the server room too?

It is better to give the server room its own unit, so it keeps cooling when the office system is off or heating. See office air conditioning.

Call 01772 288651 or use the form below to book a free survey. We will look at your premises, recommend the right system and give you a clear written quote.

Last updated: November 2026.