For a home office, first cut solar and equipment heat, then size cooling for the room's actual daytime use. A small split system can provide quiet, steady cooling and efficient heating where properly designed, while a portable exhaust-hose unit suits occasional or non-permanent use but is noisier beside a desk. Check electrical, planning and noise implications before installing fixed equipment.
Identify the heat sources
Home offices can overheat even when small because computers, monitors, lighting and occupants release heat throughout the working day. South-facing glazing and lightly built garden-room walls or roofs may add a larger solar load.
Record indoor conditions and sun exposure during working hours. Turn off unused equipment, use efficient devices and chargers, and keep ventilation openings clear before concluding that mechanical cooling is required.
Apply passive cooling first
Shade glazing before direct sun arrives. External shading is often most effective, subject to the building and permissions. Secure cross-ventilation can help when outdoor air is cooler, while roof and wall insulation can moderate temperature swings in lightweight garden buildings.
These measures reduce running time and may improve video-call acoustics by allowing windows to stay closed for shorter periods. They should remain part of the solution even after cooling is installed.
Portable or fixed cooling
A portable air conditioner can be moved and avoids a permanent condenser, but its compressor and airflow are close to the microphone. The exhaust hose must terminate outside through an arrangement consistent with the product instructions.
A split system moves the compressor outside and usually provides more stable control. A reversible model can also heat a detached office. The installer should assess both summer gain and winter heat loss, rather than sizing for one season and assuming the other.
- Place the indoor airflow away from the desk and papers.
- Check sound at the fan speed needed during calls.
- Use controls that avoid cooling an empty office.
- Plan safe filter and outdoor-unit access.
Detached offices and permissions
A garden office may need a dedicated electrical check and a weatherproof route for services. Condensate must not create slippery paths or nuisance at a boundary. The outdoor unit needs free airflow and should not be boxed in for appearance.
Outbuilding and heat-pump planning rules do not make every proposal automatically permitted. Check the property, location and equipment against current requirements, and consider nearby homes before selecting a condenser position.
Frequently asked questions
Will a desktop fan cool a home office?
A fan can improve personal comfort by moving air but does not lower the room's air temperature. It may be enough when heat and humidity are moderate.
Can a split system heat a garden office in winter?
A reversible air-to-air heat pump can provide space heating, but it must be selected against the office's winter heat loss and expected outdoor conditions.
Should I size cooling for all computer equipment at full load?
The design should use realistic simultaneous loads and usage. Provide the installer with equipment details and normal working patterns rather than relying on a generic allowance.
Can I hide the outdoor unit in a cabinet?
Do not enclose it unless a purpose-designed arrangement meets the manufacturer's airflow and service-clearance requirements. Restricting airflow can harm performance and reliability.
Related guides
Sources and further reading
How this guide was prepared
This guide was written by the Local AC Installers Editorial Team. We compare official guidance, legislation and established consumer information, separate general information from project-specific advice, and show publication dates and sources. We do not accept installer accreditation claims at face value.