Split Unit Aircon Installation: Complete Guide
Key takeaways
- A split unit has an indoor head and an outdoor condenser joined by refrigerant piping, so placement of both units decides how well it cools.
- Size the unit to the room, not the price tag: roughly 500 to 600 BTU per square metre, then add for sun, kitchens and extra people.
- An electrical Certificate of Compliance is legally required in South Africa for the circuit feeding your aircon, and the gas side needs its own registered signature.
- Oversizing is a common and costly mistake: US Department of Energy research links oversized systems to 10 to 15 percent higher energy use plus faster wear.
- Get a free written quote before you commit, so pricing, warranty and scope are agreed in writing.
A split unit aircon installation involves mounting an indoor head inside your room, fixing an outdoor condenser to a wall or slab outside, and running insulated copper refrigerant piping and cabling between them. Done properly, that is a half-day job for a qualified team, and it gives you quiet, efficient cooling for years. This guide walks Gauteng homeowners and business owners through how these systems work, how to size one, what the law requires, and the mistakes that turn a good unit into an early repair bill.
At Airconmaster we install split systems across Johannesburg, Pretoria, Centurion, Midrand, the East Rand, West Rand and the Vaal every week, so the advice below reflects what actually holds up through our summer heat and load-shedding surges.
How Split Unit Aircon Installation Works and Where to Mount the Units
A split system has two parts. The indoor unit blows conditioned air into your room and holds the evaporator coil and filters. The outdoor unit holds the compressor and condenser, and it dumps the heat from your room outside. The two are joined by refrigerant piping, a drain pipe and electrical cabling.
Where you put each unit matters more than most people expect.
Indoor unit placement:
- Mount it high on the wall so cool air spreads across the room.
- Avoid blowing air directly onto a bed, desk or dining table.
- Keep it clear of curtains, shelves and cupboards that block airflow.
- Leave space for the drain pipe to fall away with a steady gradient.
Outdoor unit placement:
- Choose a shaded, well-ventilated spot, ideally out of direct afternoon sun.
- Keep it off the ground on brackets or a slab so it stays clean and level.
- Leave breathing room around the fan so hot air can escape.
- Position it as close to the indoor unit as practical to keep the pipe run short.
Long, badly routed pipe runs are one of the quiet reasons a system underperforms, so a technician plans both positions before drilling anything.
Sizing Your Unit Correctly for Room Size and Sun Exposure
Buying too small means the aircon runs flat out and never quite cools. Buying too large means it short cycles, leaves the room clammy, and wears out sooner. Correct sizing sits at the heart of a good install.
A practical starting point is roughly 500 to 600 BTU per square metre for a standard room with a 2.4 metre ceiling. So a 20 square metre lounge lands around 12,000 BTU before adjustments.
Then you adjust for real conditions:
- Sun exposure: West- and north-facing rooms that bake through a Highveld afternoon need more capacity.
- Ceiling height: Double-volume rooms and high ceilings hold more air to cool.
- Kitchens: Add capacity for the heat from stoves and ovens.
- Occupancy: Busy offices and living rooms with several people need extra cooling.
- Glass: Large windows and sliding doors add heat load.
Getting this right is why a proper installer measures your space rather than guessing from a floor plan. If you are still weighing your options, our comparison of a portable AC versus a split unit helps you decide before you spend.
Electrical and COC Requirements for a Compliant Install
This is the part people skip and later regret. In South Africa, an aircon install has two separate compliance sides, and both are legal requirements.
The electrical side is governed by the Occupational Health and Safety Act and the Electrical Installation Regulations. The circuit feeding your aircon must be certified with an electrical Certificate of Compliance, issued by a registered person. You can read the official position on this from the Electrical Certification Board of South Africa, which oversees the COC system.
A compliant install typically means:
- A dedicated, correctly rated circuit and breaker for the unit.
- Proper isolation so the aircon can be switched off safely for service.
- Wiring that meets the current SANS 10142 wiring code.
- A COC covering the electrical work once it is done.
The refrigerant side is separate. The gas connection and pressure testing must be handled and signed off by a registered gas practitioner. Airconmaster uses licensed and insured technicians and registered electricians, so both certificates are covered under one booking, along with a workmanship guarantee that protects you long after install day.
What a Professional Installation Day Looks Like
A tidy, well-run install day usually follows the same rhythm. For a single split unit, expect roughly three to five hours with one team.
- Site check and planning. The technician confirms indoor and outdoor positions, the pipe route, and the electrical supply.
- Mounting the indoor unit. A level bracket goes up, and a neat hole is cored through the wall for the piping.
- Fitting the outdoor unit. The condenser is fixed to brackets or a slab, level and clear of obstructions.
- Connecting pipework and cabling. Copper refrigerant lines, drain and cabling are run, insulated and neatened.
- Vacuum and pressure test. The lines are vacuumed to remove moisture and air, then tested for leaks. This step is easy to rush and vital to skip nothing.
- Charging and commissioning. Refrigerant is set correctly, the system is switched on, and cooling is checked.
- Certification and handover. You get your COC, a workmanship guarantee, and a walkthrough of how to run and maintain the unit.
A good team leaves the site clean, labels the isolator, and confirms the warranty in writing before they pack up.
Common Installation Mistakes That Cause Future Breakdowns
Most aircon call-outs we attend in Gauteng trace back to how the unit was installed, not the brand on the box. The usual culprits are avoidable.
- Oversizing the unit. It feels like buying comfort, but US Department of Energy research links oversized systems to 10 to 15 percent higher energy consumption along with more wear and worse humidity control.
- Skipping the vacuum step. Moisture and air left in the lines corrode components and rob the system of cooling.
- Sloppy drain gradient. A drain that does not fall properly leaks water down your wall.
- Poor outdoor placement. A condenser baking in full sun or boxed into a tight corner runs hot and struggles.
- Undersized or shared electrical circuits. These trip breakers and stress the compressor, especially during load-shedding recovery.
- No COC or gas certificate. This leaves you legally exposed and voids most warranties.
Inverter split systems can save a meaningful chunk of running costs compared with older fixed-speed units, so a rushed install throws away the very efficiency you paid for. Careful sizing, a proper vacuum and clean pipework are what keep those savings real over the years.
Getting a Free Installation Quote
A written quote protects you. It fixes the unit, the scope, the price and the warranty before anyone drills a hole, so there are no surprises on the day. When you compare quotes, check that the price includes the COC, the gas certificate, mounting hardware and commissioning, not just the unit and a headline figure.
Airconmaster gives upfront written quotations, backs work with a parts warranty and workmanship guarantee, and brings 15-plus years of local experience to every install across Gauteng. We offer same-day and 24/7 emergency call-outs when you need help fast.
To book a licensed technician or get your free written quote, call 060 959 2231, send a WhatsApp to the same number, or request a quote through our website. Tell us your room size and where you are, and we will help you choose the right split unit and get it installed compliantly.
Frequently asked questions
How long does a split unit aircon installation take?
A standard single split unit usually takes three to five hours for one team. Multi-head systems, long pipe runs or difficult wall access can push it to a full day.
Do I legally need a Certificate of Compliance for my aircon in South Africa?
Yes. Under the Occupational Health and Safety Act and the Electrical Installation Regulations, the electrical circuit feeding your aircon must be certified by a registered person. The refrigerant side also needs a registered gas practitioner.
What size aircon do I need for my room?
Start at roughly 500 to 600 BTU per square metre, then adjust up for west-facing rooms, high ceilings, kitchens and rooms with several people. A technician confirms the load on site.
Can I install a split unit aircon myself?
No. The refrigerant handling and electrical connection both require registered practitioners in South Africa, and a DIY install voids most warranties and your COC.
How much does split unit aircon installation cost in Gauteng?
It depends on the unit size, pipe length and wall access. The honest answer is to get a free written quote so the price and scope are fixed before work starts.
Talk to a qualified technician
Free assessment, written quotation, same-day response across Gauteng.