When temperatures fall, one of the most common arguments in an office is also one of the hardest to settle:
What temperature should we actually set the air conditioning to?
One person wants 23°C. Someone else is opening a window. Another employee has a portable heater under the desk while the air-conditioning system is still operating.
Apart from making the office uncomfortable, competing heating and cooling can waste a considerable amount of energy.
For businesses using modern commercial air conditioning for winter heating, getting the temperature and controls right can improve comfort while reducing unnecessary energy use.
Is There a Legal Office Temperature in the UK?
UK workplace regulations do not specify one exact temperature that every office must maintain.
Workplace regulations require indoor workplace temperatures to be reasonable.
Health and Safety Executive guidance says workplace temperatures should normally be at least 16°C, or at least 13°C where work involves rigorous physical effort.
Those figures are minimum guidance rather than recommended thermostat settings for a typical office.
For a normal sedentary office, the aim should be comfortable working conditions rather than simply achieving the legal minimum.
Is 19°C a Good Office Temperature?
For many offices, approximately 19°C can be a sensible starting point for winter heating.
That does not mean 19°C is the correct temperature for every building.
Thermal comfort is affected by much more than the number shown on the controller.
Factors include:
- Air movement
- Humidity
- Radiant heat from windows
- Clothing
- Physical activity
- Solar gain
- Equipment heat loads
- Where people sit within the room
A well-controlled office may therefore feel more comfortable at 19–21°C than a poorly controlled office set to 23°C.
Avoid Constantly Changing the Controller
One common misconception is that setting the thermostat much higher will heat the room faster.
If the office is 17°C, increasing the controller from 20°C to 28°C will not normally make an appropriately operating system heat the room significantly faster.
Instead, it can result in the room becoming too warm once the required temperature is reached.
A better approach is to select a sensible set point and allow the system to regulate the temperature automatically.
Do Not Heat and Cool at the Same Time
This sounds obvious, but it happens surprisingly often in commercial buildings.
Examples include:
- One zone operating in heating while an adjacent system is cooling
- Windows being opened because an area is overheating
- Portable electric heaters being used underneath an air-conditioning unit
- Different occupants repeatedly changing local controllers
This creates competing heating and cooling loads and can increase energy consumption considerably.
Where a building has multiple indoor units or a VRF system, the control settings should be reviewed so that different areas are not fighting against each other unnecessarily.
Modern heat-pump systems for businesses can provide both heating and cooling, but good control is essential to get the best performance from them.
Use Timers and Occupancy Schedules Properly
Leaving commercial air conditioning operating continuously is rarely necessary in a conventional office.
Start and stop times should reflect the actual occupancy of the building.
Depending on the property, it may be sensible to allow the system to start shortly before employees arrive rather than keeping it running throughout the night.
Heating and air-conditioning operating times should also be reviewed when working hours change, daylight-saving time changes or areas of the building are no longer occupied.
For larger properties, centralised controllers or building-management systems can make this much easier.
Why Does One Part of the Office Feel Colder?
If one area remains uncomfortable even though the thermostat says the room is at temperature, simply increasing the set point may not solve the real problem.
Common causes include:
- Poorly positioned indoor units
- Blocked filters
- Restricted airflow
- Draughts
- Large areas of glazing
- Different solar gains between parts of the building
- Incorrectly positioned temperature sensors
- Poor air distribution
Persistent hot or cold areas should be investigated rather than compensating by overheating the entire office.
If your system is running but still struggling to maintain comfortable temperatures, our guide to commercial air conditioning not cooling properly explains some of the most common warning signs.
Should Commercial Air Conditioning Be Serviced Before Winter?
If the system provides both summer cooling and winter heating, autumn is a particularly useful time to identify developing faults.
Commercial air-conditioning systems used throughout the year need maintenance appropriate to their operating hours, environment and manufacturer requirements.
A professional commercial air-conditioning service can help identify issues such as:
- Dirty filters
- Restricted heat exchangers
- Controller faults
- Weak airflow
- Condensate problems
- Electrical issues
- Equipment that is not changing correctly between cooling and heating modes
Preventative maintenance can also reduce the likelihood of an unexpected breakdown during colder weather.
Frequently Asked Questions
What Is the Recommended Office Temperature in Winter in the UK?
There is no single compulsory thermostat setting for every office.
For many commercial offices, around 19–21°C can provide a sensible starting point, although the right temperature depends on the building, occupants and working conditions.
Is 22°C Too Hot for an Office?
Not necessarily, but many offices can remain comfortable at a lower setting.
Excessively high temperatures can increase energy consumption, particularly where occupants then open windows or use cooling to compensate.
Does Turning the Thermostat Up Heat an Office Faster?
Generally, no.
The thermostat primarily determines the target temperature rather than acting like an accelerator.
Can Commercial Air Conditioning Heat an Office Efficiently?
Yes.
Most modern commercial split and VRF air-conditioning systems operate as reversible air-to-air heat pumps and can provide both cooling and heating.
If you are considering using air conditioning as part of your building’s heating strategy, you can read more about our commercial heat-pump solutions.
Why Does Our Office Feel Cold Even Though the Thermostat Says 21°C?
Air temperature is only one part of thermal comfort.
Air movement, glazing, humidity, sensor position and airflow distribution can all influence how comfortable the occupants feel.
Make Your Existing System Work Properly This Winter
If your office has uneven temperatures, high running costs or air conditioning that struggles in heating mode, adjusting the thermostat repeatedly may simply be masking another problem.
Aircon Services provides commercial air-conditioning installation, servicing and maintenance for businesses across Oxfordshire, Buckinghamshire, London and surrounding areas.
If you would like your system checked before winter demand increases, contact Aircon Services to arrange a commercial air-conditioning service or assessment.
