Air conditioning in a renovation: when to run the lines

Why you can't “just hang it later”

An air conditioner line is copper pipes, a cable and a drain hidden in the wall. If it isn't run before plastering, there are two options left: chase the finished walls or run the line in a trunking on the wall. That's why in the app's route the “Air conditioning” stage sits between “Electrical” and “Ventilation”, before “Rough finishing”. The last item of the “Electrical” stage is a reminder: plastering can only start after the wiring and all the lines in the walls - air conditioning and ventilation - have been accepted.

The “Air conditioning” stage is “if planned”: if you answered in the survey that there will be no air conditioners, the app removes it. The air conditioning items are currently a draft: a builder is reviewing them, and the wording may change.

Step 1. Planning: models and unit locations

“Planning” has the “Choose air conditioners and unit locations” item. What to decide:

• models and output - the line diameter and the circuit breaker in the panel depend on them;
• indoor unit locations - with the furniture in mind: think about where the airflow will go, preferably not onto the bed or a workplace;
• outdoor unit locations - with the facade in mind. Ask building management whether the building has rules on where outdoor units may go;
• where the condensate goes - by gravity to a discharge point or through a pump.

Book the installation at the same time. The route's hint: in May-August installers are booked 2-4 weeks ahead.

The air conditioning decision is part of the overall list of building systems, together with underfloor heating, fresh-air ventilators and leak protection. More in Planning an apartment renovation: what to decide before work starts.

Step 2. The rough stage: lines before plastering

The items of the “Air conditioning” stage:

1. Run refrigerant lines. Copper pipes, cable and insulation between the indoor and outdoor units.
2. Set up condensate drainage. A drain line with a fall to the discharge point, or a condensate pump. The route's hint: get the fall wrong and it will leak on the very first hot day.
3. Prepare the power supply. A separate line to each indoor unit. It's laid together with the wiring, before plastering - so it's handy to discuss the air conditioners with the electrician in advance.
4. Pressure-test the lines. Tightness is checked under pressure before the walls are closed: otherwise a leaking line only shows up after start-up.
5. Accept the lines before plastering. Check the lines, drainage and power and save the photos.

What to photograph

Photograph every line with a tape measure in the shot before plastering: from the photo it will be found when someone drills the wall for a shelf or a curtain rail. Shoot the whole wall from corner to corner, then the joints close up, and label the room. After plastering, the lines are only visible in the photos.

Which other work is photographed before it's covered is in Photos of hidden work.

Step 3. Final installation: units and start-up

The indoor and outdoor units are mounted during the “Final installation” stage, after the walls are painted - otherwise they'll have to come down for finishing. The items:

• Install the units and start up the system - mount the units, vacuum the system and commission it;
• Check the air conditioners - in cooling and heating modes.

Upload the equipment manuals and warranty to the app: the “Documents” tab, the “Spec sheets” folder. What else goes in at the end of a renovation is in Final installation: sockets, fixtures, doors.

How to accept the lines

At acceptance, while the walls are open, check:

• the lines go to where the units will be according to the plan;
• the pipe insulation is intact, with no tears;
• the drain has a fall or there's a pump;
• each indoor unit has its own power line;
• the pressure test was done before closing;
• photos of every line with a tape measure are in the app.

The contractor checks off the items and taps “Send for review”. You or the designer look at the photos and tap “Accept work” or “I have remarks”. How this works is in How to accept a crew's work stage by stage.

Common mistakes

• No model chosen before the lines - the pipe diameter and the panel breaker may not fit.
• Power forgotten - after plastering, a line to the unit can't be added without chasing.
• No fall on the drain - condensate will run down the wall.
• No pressure test - a leak will only be found after start-up.
• The line not photographed - a year later someone drills through it.
• Units hung before painting - they'll be taken down for finishing.

Checklist

• Models and unit locations are chosen at planning, and the installation is booked.
• Power lines are laid together with the wiring.
• Lines, drainage and power are run before plastering.
• The pressure test is done, the lines are accepted, the photos are saved.
• The units are hung after the walls are painted, and the system is started.
• Cooling and heating are checked; manuals and warranty are in “Documents”.