A reversible air-to-air job is decided by three things, and price is not one of them. The load has to be worked out room by room rather than from a floor area, because a south-facing glazed living room and a north-facing bedroom do not call for the same output and an oversized unit cycles, dehumidifies badly and costs more to run. The refrigerant has to sit inside the F-Gas regime of Regulation (EU) 2024/573, which governs both the fluid and the leak-checking duties that follow the charge. And the commissioning has to be evidenced: vacuum pulled with a gauge, tightness tested with dry nitrogen before the valves are opened, condensate run checked. The table below sets out what a compliant machine has to show on paper.
| What to check before ordering | Mono-split | Multi-split |
|---|---|---|
| Heating class, SCOP | The higher band | One band below is common |
| Cooling class, SEER | The higher band | One band below is common |
| Refrigerant | Compliant with Regulation (EU) 2024/573 | Same |
| Connectivity | Remote control and setpoint logging | Same |
| Installation | Fixed and permanent, portable units excluded | Same |
| Dwelling | Existing stock, retrofit | Same |
Understanding reversible air conditioning (air-to-air heat pump) and its uses
Difference between air conditioning, an air-to-air heat pump and a reversible system
Air conditioning mainly refers to cooling a dwelling. An air-to-air heat pump is a heat pump that captures heat from the outdoor air and transfers it indoors via an outdoor unit and one or more indoor splits. When it's described as reversible, the same equipment can also produce cooling. In practice, people often say "reversible AC", but the key point remains the heat transfer, not the cooling production.
Heating and cooling modes: simple operation to explain to the client
In heating mode, the machine draws energy from the outdoor air, even in cool weather, and releases it into the room. In cooling mode, the reversed cycle removes heat from the room to the outside. The client can keep one simple idea in mind: heat is moved from one side to the other, controlled by a thermostat and remote control.
Mono-split, multi-split, ducted: choosing the right configuration for the dwelling
A mono-split heats or cools a single zone, practical for a living room or one floor. A multi-split feeds several rooms, useful when needs differ from bedroom to bedroom. Ducted systems are discreet, with ceiling grilles and a duct network. They need space in the false ceiling and careful sizing, to aim for the right output without over-equipping. To go further, also see choosing between an air-to-air and an air-to-water heat pump.
Properly sizing air conditioning to avoid discomfort and overconsumption
On-site criteria: floor area, insulation, exposure, internal gains and number of rooms
Before choosing the output, start from the site. Floor area and ceiling height, insulation quality, airtightness, exposure, solar protection, internal gains (kitchen, IT equipment) and number of rooms. A fully glazed south-facing living room is not treated like a north-facing bedroom, and it is the cooling capacity calculation by volume that puts a figure on that gap. In renovation, an improvement to insulation or shutters can significantly reduce the cooling need.
Output, airflow, unit placement: points of vigilance in renovation
Aim for air conditioning able to cover the summer load without cycling erratically. Favour a well-tuned Inverter unit. Check the airflow and diffusion to avoid direct draughts. On the installation side, plan ahead for the placement of the indoor units, the routing of the lines, condensate drainage, acoustics and maintenance access. That layout work can be prepared at the desk, with the indoor units positioned on the plan and the coverage rate calculated room by room.
Common mistakes (oversizing, poor placement) and corrective solutions
Oversizing makes the machine cycle, dehumidifies poorly, and can lead to overconsumption. Poor placement creates cold zones and hot zones. Solutions. Recalculate room by room, adjust the setpoint, add solar protection, balance the shading, or use finer zoning. Have it validated by a competent professional, F-Gas certified for the refrigerant circuit.
Installation and commissioning: the key steps for reliable, quiet air conditioning
Site preparation: support, condensate drainage, penetrations and sealing
Before installing air conditioning, everything hinges on placement. The outdoor unit is fixed on anti-vibration mounts and a sound wall, with proper distances kept for airflow and noise. Condensate drainage is planned from the start. A continuous slope, a trap if needed, and controlled discharge. Wall penetrations are made with a sleeve, then careful air and water sealing to prevent infiltration.
Connections, vacuum pull-down, leak testing: what makes the difference
Fittings torqued correctly, insulated refrigerant lines, and clean brazing. The vacuum pull-down is done with a vacuum gauge, not "by feel", to remove moisture. Then a dry-nitrogen leak test before opening the valves and releasing the refrigerant. This is also the moment to check compliance related to refrigerants.
Settings, tests and usage explanations: handing over a system that delivers on its promises
Finish with fine-tuning. Test heating and cooling modes, check temperatures, airflow, condensate and noise level. Then move to the practical side. Filter cleaning, instructions, night mode, and a reminder about maintenance. A clear handover avoids 80% of the "it's making noise" callbacks.
Regulation, maintenance and best practices in 2026
Handling refrigerants: obligations, certificates and traceability
On an air conditioning system, any intervention on the refrigerant circuit (recovery, charging, evacuation) remains reserved for certified professionals. The company must hold a capability certificate. The technician, a competency certificate. Keep a refrigerant log (quantities, sources, recoveries) and retain the supporting documents. In the event of a leak, finding and fixing it takes priority over any top-up.
Maintenance, cleaning, performance checks: a recommended schedule for your clients
Simple advice. Dust off filters every 1 to 2 months during the season. Clean the heat exchangers and check the condensate at least once a year. For many systems, biennial maintenance is required between 4 and 70 kW, and every 5 years above that. Use the visit to check tightness, airflow and controls.
Optimising service life: usage tips (temperatures, scheduling, humidity management)
Aim for a reasonable gap between indoor and outdoor temperatures, rather than a big blast of cold. Schedule the time slots, avoid repeated on/off cycling, and keep the grilles clear. In the shoulder seasons, dehumidification mode limits discomfort and eases the load on the compressor.
Selling and quoting reversible air conditioning without wasting time
The right arguments: summer/winter comfort, savings, improved energy performance of the dwelling
Reversible air conditioning is a single piece of equipment that cools in summer and heats in winter. Sell the immediate comfort and room-by-room control. On the bill side, emphasise the air-to-air heat pump principle, often more efficient than direct electric heating. And on the EPC, a controllable, efficient system can lift the dwelling's rating, provided it is properly sized (see the design external temperature).
A clear quote: essential line items (supply, lines, accessories, commissioning, options)
A readable quote avoids 3 rounds of back-and-forth. Clearly distinguish:
- Supply (outdoor unit, indoor units, remote controls).
- Refrigerant lines, wiring, condensate drainage, drilling and patching.
- Accessories (mounts, trunking, anti-vibration mounts, electrical protection).
- Vacuum pull-down, charging if needed, commissioning and checks.
- Options (multi-split, ducted, condensate lift pump, Wi-Fi module, maintenance contract).
Typical client cases: apartment, older house, converted loft (what to propose and why)
Apartment. Often a mono-split, with care over noise, placement and co-ownership approval. Older house. Propose a multi-split or ducted system, linking the sizing to the insulation and usage. Converted loft. Favour even distribution (ducted or console unit), and secure maintenance access. A tailored proposal gets quoted faster, and gets signed with more confidence.
