Split air conditioning, sized for the room and ready to connect
A split system is two boxes joined by a pair of copper refrigerant pipes, a control cable and a condensate drain. Choose single split for one room or multi split for up to five, size each room, and the kit builder below adds the indoor and outdoor units plus the pipework, cables, isolator, drainage and bracket each model actually needs.
Supply only. Refrigerant systems must be installed and commissioned by an F-Gas certified engineer; we verify F-Gas certification before dispatching refrigerant-charged equipment.
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Single split or multi split?
A single split pairs one indoor unit with its own outdoor unit. It is the simplest and usually the cheapest way to cool and heat one room, and the outdoor unit can be matched exactly to that room. A multi split runs two to five independently controlled indoor units from one outdoor unit, which keeps the outside of the building tidy and shares one electrical supply. Each room still gets its own pair of refrigerant pipes and its own control cable back to the outdoor unit.
- One room, or rooms far apart on opposite sides of the house: single split for each.
- Two to five rooms within roughly 20–25 m pipe run of one outdoor position: multi split.
- More than five rooms, or a commercial or multi-tenant building: several systems or VRF; ask us for a design quote.
Our multi split range is Panasonic Free Multi Z (R32). Every Panasonic wall unit in the TZ range and the floor consoles we list can be mixed on the same outdoor unit, subject to Panasonic’s combination table.
How big an air conditioner does each room need?
Cooling load depends on floor area, ceiling height, glazing, how much sun the room gets and what happens in it. The builder uses about 110 W of cooling per m² for a 2.4 m ceiling, then adjusts for sun, insulation and room use. As a starting point:
| Room | Floor area | Typical unit size | Examples we stock |
|---|---|---|---|
| Small bedroom, study | up to 12 m² | 2.0–2.5 kW | Panasonic TZ 2.0/2.5, Ariston Prios Net 25, Worcester Bosch CL3000i 2.6 |
| Double bedroom, office | 12–20 m² | 2.5 kW | Worcester Bosch CL7000i-Set 26, Panasonic TZ 2.5 |
| Main bedroom, lounge | 20–30 m² | 3.5 kW | Ariston Prios Net 35, Panasonic TZ 3.5 single split |
| Large lounge, kitchen-diner | 30–45 m² | 5.0–5.3 kW | Ariston Prios Net 50, Worcester Bosch CL3000i 5.3 |
| Open-plan living | 45–60 m² | 6.0–7.0 kW | Ariston Prios Net 70, Worcester Bosch CL3200i 7.0 |
| Very large, south-facing glazing | 60 m² + | 7.0 kW or two units | Two single splits or a multi split |
Add a size if the room has large south or west-facing windows, sits under a hot roof, or is a kitchen or busy office. For a full calculation try our BTU calculator.
Pipe sizes and electrical connection for every model we list
This is the information an installer needs before ordering pipe and cable. Pipe sizes are the flare connections on the units; the electrical columns show the circuit protection the manufacturer specifies and where the supply connects. Figures marked * are from range data rather than the model’s installation manual, so confirm them on site. All units are single phase, 230 V.
| Model | Type | Capacity | Liquid / gas pipe | Supply connects to | MCB / fuse | Suggested supply cable | Indoor–outdoor cable | Max pipe run |
|---|---|---|---|---|---|---|---|---|
| Ariston Prios Net 25 MUA1 | Single split set | 2.6 kW | 1/4″ / 3/8″ | Outdoor unit (3G 1.5 mm² H07RN-F lead) | 10 A | 2.5 mm² | 5G 1.5 mm² H07RN-F (W-1L-2N-S-⏚) | 25 m (10 m vertical; +12 g/m R32 beyond 5 m) |
| Ariston Prios Net 35 MUA1 | Single split set | 3.5 kW | 1/4″ / 3/8″ | Outdoor unit (3G 1.5 mm² H07RN-F lead) | 16 A | 2.5 mm² | 5G 1.5 mm² H07RN-F (W-1L-2N-S-⏚) | 25 m (10 m vertical; +12 g/m R32 beyond 5 m) |
| Ariston Prios Net 50 MUA1 | Single split set | 5.3 kW | 1/4″ / 1/2″ | Outdoor unit (3G 2.5 mm² H07RN-F lead) | 16 A | 2.5 mm² | 5G 2.5 mm² H07RN-F (W-1L-2N-S-⏚) | 30 m (20 m vertical; +12 g/m R32 beyond 5 m) |
| Ariston Prios Net 70 MUA1 | Single split set | 7.0 kW | 3/8″ / 5/8″ | Outdoor unit (3G 2.5 mm² H07RN-F lead) | 20 A | 2.5 mm² | 5G 2.5 mm² H07RN-F (W-1L-2N-S-⏚) | 50 m (25 m vertical; +24 g/m R32 beyond 5 m) |
| Worcester Bosch CL7000i-Set 26 E | Single split set | 2.5 kW | 1/4″ / 3/8″ | See wiring diagram | 16 A | 2.5 mm² | 4-core 1.5 mm² | 25 m |
| Worcester Bosch CL7000i-Set 35 E | Single split set | 3.4 kW | 1/4″ / 3/8″ | See wiring diagram | 16 A | 2.5 mm² | 4-core 1.5 mm² | 25 m |
| Worcester Bosch CL7000i-Set 53 E | Single split set | 5.0 kW | 1/4″ / 1/2″ | See wiring diagram | 16 A | 2.5 mm² | 4-core 1.5 mm² | 30 m |
| Worcester Bosch Climate CL3200i-Set 26 WE (2.6 kW) | Single split set | 2.6 kW | 1/4″ / 3/8″ | Outdoor unit | 13 A | 2.5 mm² | 5-core H07RN-F ≥1.5 mm² (W-L-N-S-⏚) | 25 m (10 m vertical; +12 g/m R32 beyond 5 m) |
| Worcester Bosch Climate CL3200i-Set 35 WE (3.5 kW) | Single split set | 3.5 kW | 1/4″ / 3/8″ | Outdoor unit | 13 A | 2.5 mm² | 5-core H07RN-F ≥1.5 mm² (W-L-N-S-⏚) | 25 m (10 m vertical; +12 g/m R32 beyond 5 m) |
| Worcester Bosch Climate CL3200i-Set 53 WE (5.3 kW) | Single split set | 5.3 kW | 1/4″ / 1/2″ | Outdoor unit | 16 A | 2.5 mm² | 5-core H07RN-F ≥1.5 mm² (W-L-N-S-⏚) | 30 m (20 m vertical; +12 g/m R32 beyond 5 m) |
| Worcester Bosch Climate CL3200i-Set 70 WE (7.0 kW) | Single split set | 7.0 kW | 3/8″ / 5/8″ | Outdoor unit | 25 A | 2.5 mm² | 5-core H07RN-F ≥2.5 mm² (W-L-N-S-⏚) | 50 m (25 m vertical; +24 g/m R32 beyond 5 m) |
| Panasonic CU-TZ35CKE (TZ 3.5 kW outdoor) | Single split outdoor | 3.5 kW | 1/4″ / 3/8″ | Indoor unit | 16 A | 2.5 mm² | 4-core 1.5 mm² H07RN-F | 15 m |
| Panasonic CU-2Z41CBE Free Multi 4.1 kW | Free Multi outdoor | 4.1 kW | 1/4″ / 3/8″ | Outdoor unit | 16 A | 2.5 mm² | 4-core 1.5 mm² H07RN-F per room | 20 m each / 30 m total |
| Panasonic CU-3Z52CBE Free Multi 5.2 kW | Free Multi outdoor | 5.2 kW | 1/4″ / 3/8″ | Outdoor unit | 16 A | 2.5 mm² | 4-core 1.5 mm² H07RN-F per room | 25 m each / 50 m total |
| Panasonic CU-3Z68CBE Free Multi 6.8 kW | Free Multi outdoor | 6.8 kW | 1/4″ / 3/8″ | Outdoor unit | 20 A | 2.5 mm² | 4-core 1.5 mm² H07RN-F per room | 25 m each / 60 m total |
| Panasonic CU-4Z68CBE Free Multi 6.8 kW | Free Multi outdoor | 6.8 kW | 1/4″ / 3/8″ | Outdoor unit | 20 A | 2.5 mm² | 4-core 1.5 mm² H07RN-F per room | 25 m each / 60 m total |
| Panasonic CU-4Z80CBE Free Multi 8.0 kW | Free Multi outdoor | 8.0 kW | 1/4″ / 3/8″ | Outdoor unit | 25 A | 4.0 mm² | 4-core 1.5 mm² H07RN-F per room | 25 m each / 70 m total |
| Panasonic CU-5Z90CBE Free Multi 9.0 kW | Free Multi outdoor | 9.0 kW | 1/4″ / 3/8″ | Outdoor unit | 25 A | 4.0 mm² | 4-core 1.5 mm² H07RN-F per room | 25 m each / 80 m total |
| Panasonic CS-MTZ16CKE TZ wall 1.6 kW | Indoor unit | 1.6 kW | 1/4″ / 3/8″ (multi only) | From outdoor unit via interconnect (multi) | — | — | 4 × 1.5 mm² H07RN-F | See outdoor unit |
| Panasonic CS-TZ20CKEW TZ wall 2.0 kW | Indoor unit | 2.0 kW | 1/4″ / 3/8″ (multi only) | From outdoor unit via interconnect (multi) | — | — | 4 × 1.5 mm² H07RN-F | See outdoor unit |
| Panasonic CS-TZ25CKEW TZ wall 2.5 kW | Indoor unit | 2.5 kW | 1/4″ / 3/8″ | From outdoor unit via interconnect (multi); indoor in single split | — | — | 4 × 1.5 mm² H07RN-F | See outdoor unit |
| Panasonic CS-TZ35CKEW TZ wall 3.5 kW | Indoor unit | 3.5 kW | 1/4″ / 3/8″ | From outdoor unit via interconnect (multi); indoor in single split | — | — | 4 × 1.5 mm² H07RN-F | See outdoor unit |
| Panasonic CS-TZ42CKEW TZ wall 4.2 kW | Indoor unit | 4.2 kW | 1/4″ / 1/2″ — expander at Free Multi port | From outdoor unit via interconnect (multi); indoor in single split | — | — | 4 × 1.5 mm² H07RN-F | See outdoor unit |
| Panasonic CS-TZ50CKEW TZ wall 5.0 kW | Indoor unit | 5.0 kW | 1/4″ / 1/2″ — expander at Free Multi port | From outdoor unit via interconnect (multi); indoor in single split | — | — | 4 × 1.5 mm² H07RN-F | See outdoor unit |
| Panasonic CS-TZ60CKEW TZ wall 6.0 kW | Indoor unit | 6.0 kW | 1/4″ / 1/2″ — expander at Free Multi port | From outdoor unit via interconnect (multi); indoor in single split | — | — | 4 × 1.5 mm² H07RN-F | See outdoor unit |
| Panasonic CS-TZ71ZKEW TZ wall 7.1 kW | Indoor unit | 7.1 kW | 1/4″ / 5/8″ — expander at Free Multi port | From outdoor unit via interconnect (multi); indoor in single split | — | — | 4 × 1.5 mm² H07RN-F | See outdoor unit |
| Panasonic CS-MZ20CFEA floor console 2.0 kW | Indoor unit | 2.0 kW | 1/4″ / 3/8″ (multi only) | From outdoor unit via interconnect (multi) | — | — | 4 × 1.5 mm² H07RN-F | See outdoor unit |
| Panasonic CS-Z25CFEAW floor console 2.5 kW | Indoor unit | 2.5 kW | 1/4″ / 3/8″ | From outdoor unit via interconnect (multi); indoor in single split | — | — | 4 × 1.5 mm² H07RN-F | See outdoor unit |
| Panasonic CS-Z35CFEAW floor console 3.5 kW | Indoor unit | 3.5 kW | 1/4″ / 3/8″ | From outdoor unit via interconnect (multi); indoor in single split | — | — | 4 × 1.5 mm² H07RN-F | See outdoor unit |
| Panasonic CS-Z50CFEAW floor console 5.0 kW | Indoor unit | 5.0 kW | 1/4″ / 1/2″ — expander at Free Multi port | From outdoor unit via interconnect (multi); indoor in single split | — | — | 4 × 1.5 mm² H07RN-F | See outdoor unit |
Supply cable sizes assume a short dedicated radial clipped direct or in conduit. Your electrician must size the cable for length, installation method and grouping under BS 7671. Panasonic specifies a polychloroprene-sheathed (H07RN-F type) 4 × 1.5 mm² interconnecting cable; Worcester Bosch Climate 3200i figures are from Bosch’s installation manual (2025/03). Ariston Prios Net figures are from Ariston’s May 2026 datasheet and the Prios Net user and installation manual. CL7000i figures marked * are from range data.
What else you need to connect a split system
Refrigerant pipework and insulation
Each indoor unit needs a liquid line and a gas line in ACR copper, sized to the unit connections in the table above. Pre-insulated pair coil is quickest: both lines come matched and insulated in a 20 m coil. Plain ACR copper coil plus Armaflex insulation suits longer runs or awkward routes. Insulate both lines separately along their full length, including the flare joints, and protect insulation outside with UV-resistant trunking. Runs longer than the factory pre-charge length need additional R32, added by the commissioning engineer.
Electrical
Give the system its own circuit from the consumer unit with the MCB rating in the table, and fit a lockable rotary isolator within sight of the outdoor unit. The indoor and outdoor units are linked by an H07RN-F interconnecting cable: four-core (live, neutral, signal, earth) on Panasonic, five-core (W, live, neutral, signal, earth) on the Worcester Bosch Climate 3200i and Ariston Prios Net, which power the indoor unit through it. Use cable glands where cables enter enclosures and keep the interconnect away from the refrigerant flare joints.
Condensate drainage
In cooling mode the indoor unit produces water. Run it in 21.5 mm overflow pipe with a continuous fall to a gully, soil stack or soakaway. Where you cannot get a fall, fit a condensate pump. In heating mode the outdoor unit also drains defrost water from its base, so do not mount it over a path.
Mounting the outdoor unit
Choose a wall bracket rated comfortably above the outdoor unit’s weight, or ground feet that lift it clear of standing water and snow. Leave the clearances in the installation manual for airflow and service access, and keep it away from bedroom windows next door for noise.
Every product in the five air conditioning collections
Live from our store, including items that are out of stock. Out-of-stock items can still be ordered on request; contact us for lead times.
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Split air conditioning questions
What is the difference between a single split and a multi split air conditioner?
A single split has one indoor unit and one outdoor unit and suits one room. A multi split connects two to five indoor units to one outdoor unit, each with its own pipes, cable and controls, so several rooms can be cooled and heated independently without several condensers on the wall.
What size air conditioner do I need for my room?
Allow roughly 110 W of cooling per square metre for a 2.4 m ceiling, then add for strong sun, poor insulation or kitchens. A 15 m² bedroom suits 2.0–2.5 kW, a 25 m² lounge 3.5 kW, a 40 m² kitchen-diner 5.0 kW and a 55 m² open-plan space 6.0–7.0 kW.
What pipe size does a split air conditioner use?
Most 2.0–3.5 kW units use 1/4 inch liquid and 3/8 inch gas lines. 5.0–5.3 kW units usually move to a 1/2 inch gas line, and 7 kW units use 5/8 inch gas with either 1/4 or 3/8 inch liquid depending on the model. Panasonic Free Multi outdoor ports are 1/4 and 3/8 inch, with expanders for larger indoor units.
What electrical supply does a split air conditioner need?
A dedicated single-phase 230 V circuit from the consumer unit with the protection the manufacturer specifies, typically 10–25 A for single splits and 16–25 A for multi split outdoor units, plus a lockable rotary isolator next to the outdoor unit. The indoor and outdoor units are linked by an H07RN-F interconnecting cable, four-core or five-core depending on the model.
Can I install a split air conditioner myself?
You can prepare the wall, brackets, trunking and drainage, but connecting, pressure testing, evacuating and charging the refrigerant circuit must be done by an F-Gas certified engineer, and the electrical circuit should be installed and certified by a qualified electrician.
How long can the pipe run be between the indoor and outdoor unit?
It depends on the model: 15 m for the Panasonic TZ 3.5 kW single split, 25–30 m for most 2.6–5.3 kW single splits, and up to 50 m for 7 kW models. Panasonic Free Multi allows 20–25 m to each indoor unit and 30–80 m in total. Longer runs need extra refrigerant beyond the pre-charge length.
Do I need a condensate pump?
Only when the condensate cannot fall continuously to a drain, for example on an internal wall or below the drain level. Otherwise a 21.5 mm overflow pipe with a steady fall is simpler and has nothing to fail.
Does a split air conditioner also heat?
Yes. Every model in this guide is a reversible inverter heat pump, giving efficient heating in winter as well as cooling and dehumidifying in summer, and they run down to about -15 to -20 °C outside.
What bracket do I need for the outdoor unit?
Choose a wall bracket rated well above the outdoor unit’s weight: a 90 kg bracket covers most single split outdoor units up to 7 kW, while the larger Panasonic Free Multi units (61–81 kg) need a 140 kg or heavier bracket, or ground feet.
What does F-Gas certification mean when I order?
Split systems contain R32 refrigerant, which UK F-Gas rules restrict to certified installers. We are required to check F-Gas certification before supplying pre-charged equipment, so complete our F-Gas form when you order or ask your installer to order.
Fitting air conditioning for customers?
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Last reviewed October 2026. Specifications are taken from manufacturer datasheets and installation instructions; always follow the instructions supplied with your units.