Home Inspection - Checking The Air-Conditioning System | Propertylogy

Home Inspection – Checking The Air-Conditioning System

By on September 20, 2017

Let’ not get into the debate of whether central or split air-conditioning systems are more energy efficient. Because every time I learn about one having an edge over another, there will always be another source with a very persuasive counter argument.

Central air-conditioning, also known as ducted air-conditioning, had been the mainstay in homes for a very long time. It uses ducting to distribute cooled air throughout a house from a single housing that contains all it’s components like compressor, evaporator, condenser, etc.

And because it can be quite lively when turned on, this unit is often vibration-mounted at places away from living space. Often in the attic or crawl space.

The split system however, is gaining a lot of traction in newer homes and especially in apartments.

It is made up of 2 parts. The compressor-condenser on the outside of a house. And the evaporator coil on the inside of a house.

Multi-split systems works like a typical split. But It enables multiple indoor units to be installed with only 1 outdoor unit. And because of the perceived energy efficiency (again, that’s up to argument) is being able to cool down individual rooms and areas instead of the whole house, it is very favored by households especially those in tropical climates.

Note that when testing or operating the compressor located outside, the temperature must not be lower than 60°F/15°C or you risk some serious damage to the machine.

Split air-conditioning systems

This system is the trend these days and we will not be talking about specifically about central systems.

Formation of ice

While the purpose of air-conditioners is to provide cooling, it is not normal for ice to collect on the units itself.

Frost on the large refrigerant suction line of the insulation is an indication of insufficient air flow. Which in turn is usually caused by collection of dirt on the evaporator coil or filter. Sometimes even due to a defective metering device.

Cold air from condensate drain line

Locate the condensate drain outflow and feel if any air is escaping from it. Cold air emerging from here is a sign that a trap is not present.

A trap like what we find underneath sinks and toilet bowls helps to reduce the loss of cold air… which is what the air-conditioner is meant for.

Wrong sloping

The drain pipe connecting the exterior and interior equipment should be checked for “correct” sloping.

I’ve witnessed poor workmanship in this area leading to water flowing in and pouring out of the internal unit like a waterfall. While it’s a beautiful sight to behold, it’s not practical in terms of housekeeping and lifespan of the system.

Evaporator on high ground

When the evaporator (cooling coil) is installed on much higher ground like the attic or at the ceiling, there is a risk of clogged primary condensate lines. This can lead to flooding of the evaporator.

To rectify this situation, a secondary drainpipe should be installed.

Unusual sounds when turned on

Don’t be foolish and trust a contractor if he says that grunting or groaning sounds are normal when air-conditioners are new or just turned on.

Unusual noises that sometimes include squealing is a sign that there is a fundamental problem with the unit and should be checked.

A regular air-conditioner operating normally should run smoothly and will at most emit a low hum.

Condenser fan

As soon as the system is switched on, the fan in the condenser should start rotating. Take a look to make sure it is doing so.

Should your view be obstructed and unable to make a visual confirmation, place your hand over the unit to feel the rushing air. You will feel the air when the air is working. And after 15 minutes of operation, the air should start to get warm.

If the air is not warm, it is an indication that the compressor is not working properly. You might need to call for servicing.

Cold low-pressure refrigerant line

After letting the air-conditioner run for at least 15 minutes, take a look at this pipe. It should be sweating as a result of condensation.

If this pipe is covered with frost, it usually means that the refrigerant is not in top condition. This can greatly affect the operating efficiency of the system.


Leaks of any kind in any area should not be ignored. If you are not sure whether a leak is really a leak, or whether a stain is supposed to be there, note it down and gather more intelligence to identify it later.

It’s not just water you are looking for. Sometimes you can encounter oil too.

Heat pumps

Heat pumps are popular in houses located in warm climates and also often found in smaller homes and condominiums.

They are basically similar to split air-conditioning systems with one major difference. It has a reverse valve that redirects the refrigerant. So instead of cooling down an area, it can also warm up an area.

They should be checked as you would on a regular split system. Also test it’s functions on thermostat to make sure it works.


Air-conditioners and heat pumps require regular servicing to ensure they continue to operate properly. Units that are not running efficiently can produce pollutants that are bad for health.

So lastly, remember to ask when was the last time they were serviced

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