25 August 2026
Summers are getting warmer, and tenants, guests and staff now expect to stay cool. For landlords, hotels, holiday lets and workplaces, the right cooling keeps people comfortable, protects bookings and reviews, and helps equipment and stock stay at a safe temperature.
This guide covers the main types of air conditioning, how to size it, what to look for, and how to install and run it safely and efficiently.
What this guide covers
Eight steps, from working out what you need to placing the order.
1
Work out what you need
Start with who the space is for, how often it gets hot and whether you can fit anything permanent.
| Property type | Priorities | Recommended approach |
|---|---|---|
| Rental properties | Tenant comfort, no permanent changes, easy replacement | Portable units that need no installation, or split systems where you own the building. |
| Hotels & serviced apartments | Quiet running, guest control, reliability | Wall-mounted split systems in each room, with simple remote or app controls. |
| Holiday lets & lodges | Comfort in peak season, low maintenance | Portable units or air coolers that can be stored over winter. |
| Offices, shops & venues | Staff and customer comfort, running costs | Split or ceiling cassette systems sized for the space and the number of people. |
2
Choose the right type
There are four main ways to cool a room, each with its own trade-offs.
Portable air conditioners
Plug in and vent hot air through a window kit. No installer needed and easy to move between rooms.
Split systems
An indoor unit on the wall and an outdoor unit outside. Quieter and more efficient, but need professional installation.
Air coolers
Cool the air by evaporating water. Low running costs and best in dry heat or well-ventilated spaces.
Fans
Move air to make people feel cooler. The cheapest option for mild weather.
3
Size it properly
Cooling power is measured in BTU (British Thermal Units). A unit that is too small runs flat out and never cools the room; one that is too big wastes energy. As a rough guide:
| Room size | Typical cooling power | Example |
|---|---|---|
| Up to about 15m² | Around 7,000 to 9,000 BTU | Bedroom or small office |
| About 15 to 25m² | Around 9,000 to 12,000 BTU | Living room or hotel room |
| About 25 to 35m² | Around 12,000 to 14,000 BTU | Open-plan living or meeting room |
| Larger spaces | Several units or a fixed system | Shops, restaurants and offices |
Pro tip
Allow more cooling for south-facing rooms, top floors, kitchens, high ceilings and rooms that fill with people or computers.
4
Features worth paying for
Heating as well as cooling
Heat pump models warm a room in winter too, so one unit works all year.
Dehumidifying mode
Takes moisture out of the air on muggy days and helps against damp.
Timers & smart control
Schedules and app control stop units running in empty rooms.
Quiet operation
Check the noise level for bedrooms and guest rooms; a sleep mode helps.
Energy rating
A more efficient rating means lower running costs over the summer.
Refrigerant
Newer models often use refrigerants with a lower environmental impact.
5
Installation & compliance
Portable units
Need a window or wall outlet for the exhaust hose and a nearby socket. Keep doors and windows closed while running.
Split systems
Must be installed by an F-gas certified engineer, who handles the refrigerant safely and records the work.
Outdoor units
Check planning rules, listed building consent and lease terms before fitting anything outside.
Electrics & drainage
Fixed systems need a suitable electrical supply and a route for condensate to drain away.
6
Running costs & efficiency
Small habits make a big difference to the cost of cooling.
Set a sensible temperature
Cooling a room a few degrees below outside is usually enough to feel comfortable.
Close up the room
Shut doors and windows, and use blinds on sunny windows.
Use timers
Cool rooms just before they are used rather than all day.
Pick the right size
A correctly sized unit runs less and lasts longer.
7
Maintenance
Filters
Clean or replace filters regularly, more often in heavy use.
Water tanks
Empty and clean the water tank on portable units and air coolers.
Annual service
Have split systems serviced once a year by a qualified engineer.
Winter storage
Store portable units clean and dry, with the hose and window kit together.
Related climate products
Dehumidifiers
Tackle condensation and damp in lodges, basements and older properties.
Heaters
Portable heat where central heating does not reach.
Air purifiers
Cleaner air in bedrooms, offices and guest rooms.
8
Procurement & efficiency
Buying cooling the same way across your properties keeps costs and maintenance under control.
Standard specification
The same models in every room make spares, filters and training simple.
Buy before the heat
Order and install ahead of summer so units are ready when temperatures rise.
Trade pricing
Buyit gives you B2B pricing on volume orders.
One supplier, several brands
Buyit brings Appliances Direct, Furniture 123, Better Bathrooms and Outdoor Living together in one B2B account.
Cooling rooms across a portfolio?
Talk to our B2B account managers about air conditioning for your properties and volume quotes.
Contact our B2B team