PRACTICAL GUIDE · UPDATED 2026-10-31
Air conditioning: cooling, heating and choosing the right system
Understand split systems, running costs and the difference between room air conditioning and a heat pump supplying radiators.
| System | Main job | Hot water |
|---|---|---|
| Room air conditioning / air-to-air | Cool rooms; reversible models also heat | Usually separate provision |
| Air-to-water heat pump | Supply a water-based heating circuit | Usually a suitable cylinder |
| Gas combi boiler | Radiators and hot water on demand | Usually no separate cylinder |
A split air-conditioning system connects an indoor unit to equipment outside. In cooling mode it moves heat out of the room. Many reversible air-to-air systems can also warm rooms. This differs from an air-to-water heat pump supplying radiators, underfloor heating and a suitable hot-water cylinder. Room air conditioning usually needs a separate solution for taps and showers.
Before buying cooling equipment, reduce unwanted solar heat with suitable shading and consider safe ventilation when outside conditions allow. An air conditioner uses electricity: cooling a room you previously left uncooled adds demand. In heating mode, costs depend on the system, weather, controls and the heating it replaces. Ask for a home-specific estimate rather than assuming a guaranteed saving.
Have the proposed installer survey the rooms and explain the required capacity, indoor and outdoor positions, airflow, noise, electrical supply and condensate drainage. Discuss a single-room system, multiple indoor units or ducted equipment, and check any planning, leasehold or listed-building restrictions before agreeing the job. Request an itemised quotation covering installation, making good, controls, warranty and ongoing maintenance.
Air conditioning commonly recirculates room air, so it does not replace the home’s ventilation. Follow the manufacturer’s user instructions for accessible filter care. Leave refrigerant, electrical and internal repair work to competent specialists. For equipment containing F gas, check the relevant company certification and the individual’s qualifications for the exact work; a Gas Safe registration or heat-pump marketing claim alone does not establish this.
Our directory keeps air-conditioning installation, servicing and repairs separate. A firm advertising installation is not automatically listed for fault repairs. Confirm your make and model, exact address, fees and appointment availability directly. These public-source listings do not yet establish a full screening pass.
Your checklist
- Explain which rooms need cooling, heating or both.
- Request a survey and compare complete installation and ongoing costs.
- Check relevant company and individual F-gas certification for the proposed work.
- Agree controls training, maintenance and warranty arrangements.
Sources & further reading
- Energy Saving Trust: Air-to-air heat pumps ↗
- GOV.UK: Company certification to work with F gas ↗
- Daikin: Surveying and sizing room air conditioning ↗
General information, not a property assessment, booking or assurance about a listed business. Dates indicate content updates; they are not invented publication dates.