An air conditioner is one of the most hard working appliances in homes & offices, especially in regions with long, hot summers. It does more than just cool a room. A well maintained unit also helps control humidity, improves indoor air quality, & keeps energy use under control. It functions through the removal of heat from the premises and expulsion out into the open air, a cycle that continues until the set point of the thermostat. Issues arise when filters get clogged, coils get dirty & leaks of the refrigerant go unchecked. Without a regular checkup, the system loses efficiency, the power bill goes up, and comfort goes until the system gets serviced/replaced.

How Air Conditioners Work?

An air conditioner is basically a heat transfer machine. It does not create cold air. It takes warm indoor air, then pulls heat out of it and releases that heat outside. The cycle repeats until the indoor temperature matches the thermostat setting.

The main parts:

Compressor: Pumps refrigerant through the system
Evaporator coil (indoor): Absorbs the heat from indoor air
Condenser coil (outdoor): Releases the heat outside
Fan units: Move air across the coils
Refrigerant: The chemical that carries heat between the indoor & outdoor units

If any of these stops doing their job properly because of dirt, leaks or age, the cooling effect drops.

Why Do They Stop Working?

Most failures are not abrupt. Smallest problems accumulate until the system fails. Typical causes:

Dirty filters: Clogged filters restrict air movement, slow cooling & can freeze the evaporator coil

Refrigerant leaks: Fewer refrigerant = not enough heat is absorbed. Air still blows, but not cool

Blocked outdoor unit: Ground dust, sand, leaves or rubble from buildings hinder heat release

Electric faults: Faulty capacitors, bad relays or loose contacts don't let the fans or the compressor start

Poor maintenance: Failing to pay attention to yearly service generates dirt accumulation in coils inside, mold formation, and high wear on parts

Once the efficiency dips, the unit takes in more power & cools less. That's when bills increase and repair bills start.

How Much Energy Do They Use

Air conditioners are usually the top energy consumer in a household. In hot climates, they can account for 40% or more of the total electricity bill during summer.

Some habits reduce this:

Set the temperature at 24°C instead of forcing it down to 18°C
Close doors & windows when the AC is running
Use curtains or blinds during peak sunlight
Clean filters regularly

Well-maintained systems can save 10 - 15% compared to neglected ones. Over the years, that difference adds up.

Types of Air Conditioners

There isn’t just one kind of air conditioner. Each type has tradeoffs.

Window units: All-in-one systems. Cheaper, but noisy. Best for small rooms
Split systems: Indoor and outdoor units. Most common for apartments and homes. Quieter and more efficient than window units
Central systems: Large units connected to ductwork. Expensive to install, effective for villas or office buildings
Portable units: Movable plugin systems. They cool less and use more electricity & can work where permanent installation isn’t possible
Inverter ACs: Adjust compressor speed instead of switching on/off. Lower power use and more stable temperature control

Choosing the wrong size unit for a room is one of the biggest mistakes people make. An undersized unit never cools enough. An oversized one shortcycles, turns on and off too often, and wears out faster.

Maintenance Basics

Clean or replace filters every month or two
Check outdoor units for obstructions. Keep space clear around them
Inspect the condensate drain line to prevent blockages and leaks
Wipe vents and grills to keep airflow unobstructed

What should you not attempt on your own?

Refrigerant checks, coil deep cleaning, and electrical repairs. Those need a licensed technician. Schedule servicing at least once a year. Twice if you run AC constantly in dusty conditions.

Signs of Trouble

Do not wait until total failure. These warning signs mean attention is needed:

Cooling takes much longer than before
Unusual noises: buzzing, clicking, grinding
Water leaks from the indoor unit
Bad smells, often mold in coils or ducts
Frequent on/off cycling

Ignoring them means the system runs harder, bills rise, and eventually the compressor burns out. Replacing a compressor often costs half or more of a new unit

Health and Air Quality

People forget that AC isn’t only about temperature. Dirty or poorly maintained systems can circulate dust, mold spores & bacteria. That is why musty smells come from neglected units.

Children, elderly people & those with allergies are more sensitive to this. Regular cleaning reduces indoor air pollution.

Repair or Replace?

The average lifespan of an air conditioner is 10 - 15 years if maintained. Beyond that, performance drops, parts get expensive, and efficiency is outdated compared to newer models.

Choose replacement if:

Repairs exceed 50% of the price of a new unit
The system is more than 12 years old
Energy bills keep climbing despite maintenance
Cooling output is poor, and comfort never improves

Newer inverter ACs can cut bills to cover their cost in a few years.

Common Mistakes People Make

Running the AC 24/7 without giving it rest
Buying a cheap, undersized unit
Neglecting maintenance until failure
Blocking vents with curtains or furniture
Trying DIY refrigerant refills without training

Each of these shortens lifespan and raises costs.

Cost of Neglect

Not maintaining an air conditioner shows up in three ways:

Bills: Higher power use
Repairs: Frequent part failures
Health: Mold, dust, poor air quality

In some cases, a yearly maintenance contract is cheaper than adhoc repairs. Many service companies offer packages that include two visits per year, cleaning, and priority repair calls.

The Practical Bottom Line

Air conditioners are simple to ignore until they stop. But the rules are straightforward: keep filters clean, service annually, and replace on time. Do that and the system works for years. Ignore it, and you’ll face breakdowns, high bills, and possibly poor indoor air.

That’s it. No mystery. Just regular attention to a machine that runs longer hours than almost anything else in your house.

FaqsShould you replace your AC before it breaks?Yes, replacing it early can prevent sudden failures, high repair costs, and rising energy bills

What is the 20 rule for air conditioners?If the repair cost times the unit’s age is over AED 5,000, replacement is usually better

What to consider before buying an AC?Check room size, energy efficiency, noise level, type of unit and maintenance needs

What is the most expensive part of an AC unit to replace?The compressor is typically the most expensive component to replace

Air Conditioner - What to know before it breaks or costs too much