In many small offices, the server, firewall and phone equipment live in a closet. It was the spare space available, the door stays shut to keep the noise down, and nobody thinks about it until something fails. Very often, the underlying cause is heat.
You do not need to become an engineer to fix this. You need to know roughly what “right” looks like and a few habits that keep it there.
Why temperature matters
Computers turn nearly all the electricity they use into heat. A rack of equipment in a small closet behaves like a space heater with the door closed.
- Performance. When processors get too hot, they slow themselves down to protect themselves. Staff experience that as a sluggish server or dropped calls.
- Reliability. Heat speeds up wear on components such as power supplies, fans and drives. Failures cause downtime and, without good backups, lost data.
- Lifespan. Equipment kept in a stable, moderate environment generally lasts longer, which delays replacement costs.
- Energy. A room that is set colder than it needs to be wastes money on cooling without adding much protection.
What the right range looks like
The reference most of the industry uses is from ASHRAE, the engineering society for heating and cooling. The current edition of its thermal guidelines for data processing environments is the fifth, published in 2021 (ASHRAE’s reference card was revised in 2024). It still recommends that air entering IT equipment be between 18°C and 27°C (about 64°F to 81°F), and says facilities should be designed and run to target that range.
ASHRAE also publishes wider “allowable” ranges that manufacturers test their equipment to handle. For the most tightly controlled class (enterprise servers and storage), that is 15°C to 32°C (about 59°F to 90°F). ASHRAE says allowable is about whether equipment works, not how reliably it lasts. Think of it as the edge of the road, not the lane. Your equipment manufacturer’s specifications take priority for any particular device.
The fifth edition also added a stricter class for high-density servers, with a recommended range of 18°C to 22°C (about 64°F to 72°F). It is up to the manufacturer whether a product falls in that class, so check the specifications for any new, powerful server. ASHRAE also has a looser class for offices and equipment rooms with minimal control, meant for gear like network switches and office PCs. That is no reason to relax: servers expect better, and the recommended range applies to all classes.
Two practical points from the same guidelines:
- Measure at the front of the equipment, where it draws air in, not at the back where hot air comes out, and not at the wall thermostat in the hallway.
- Avoid fast swings. ASHRAE limits how much the intake temperature should change: no more than 20°C (36°F) in an hour and no more than 5°C (9°F) in any 15 minutes. Steady matters as much as cool.
Our own advice for a small office is to aim for the cooler middle of the recommended range, roughly the upper 60s to mid 70s Fahrenheit, which leaves room for a hot afternoon or a failed fan.
Humidity matters too. ASHRAE sets its limits using dew point (the temperature at which moisture condenses) and relative humidity. The fifth edition raised the recommended upper limit to 70% relative humidity, but only where the air is clean; where corrosive gases are present it advises 50% or lower. Very dry air raises the risk of static discharge; damp air risks condensation and corrosion. You want neither extreme.
The Alaska angle
Our climate brings its own set of problems.
- Winter dry air. Heated indoor air in an Alaska winter can get very dry. Keep an eye on humidity in the equipment room, and handle equipment carefully to avoid static.
- Heat that assumes people. Building heat and ventilation are often set for occupied hours. A closed equipment closet can still overheat on a cold weekend, because the equipment keeps producing heat when the building ventilation is off.
- Cold equipment coming indoors. A server or switch that rode in the back of a truck or sat in a cold hangar should warm up to room temperature before you power it on, so moisture does not condense inside it.
- Summer. Long, sunny days and buildings designed for winter mean many offices have little or no air conditioning. A closet that was fine in January can run hot in July.
- Remote sites. When the nearest technician is a flight away, a cheap temperature alarm is far less expensive than a service trip.
Simple steps that help
- Put a thermometer where the air goes in. A simple digital unit with a high/low memory tells you what happened overnight.
- Get alerts, not just readings. Many servers, network switches and battery backups report their own temperatures. Networked sensors can email or text when things drift.
- Give the heat somewhere to go. A vented door, a small exhaust fan, or a dedicated cooling unit for larger rooms. Do not rely on the building’s thermostat in another room.
- Keep airflow clear. Leave space in front of and behind equipment, and do not use the room for storage.
- Clean the dust from fans and filters a few times a year.
- Consider less equipment on site. Moving some services to the cloud, or running servers as hosted virtual machines in a professionally cooled data center, reduces the heat you have to manage. It does make your Internet connection more important.
How FTI helps
As part of our managed IT services, we monitor client systems around the clock through Kaseya and act on alerts, including temperature and hardware warnings where the equipment reports them. Our AI-assisted operations look across those alerts together, so a slow rise in temperature or a string of fan warnings reaches an engineer before it becomes a failure. We can look at your equipment room, suggest practical fixes for your building, and help decide what should stay on site and what could move to a virtual server we host for you. Good cooling works hand in hand with good backup, because hardware eventually fails no matter what. Catching problems like this before they cause downtime is what proactive IT management is about.
