Over 100 million homes in North America have air conditioning. Throughout our hot, humid summers in Mexico, an air conditioner makes life more enjoyable.

Air conditioning is a process where heat and moisture are removed from the air using refrigerants and coils. The two most popular types of air conditioning systems are the central air system and the split system. A central air system is one in which there is one central cooling system that conditions the air. Ductwork distributes the cold air throughout the home.

Related: Read Part 1, the history of air conditioning, here.

But most air-conditioned homes in Mexico use the mini-split. With this system, there are no ducts to distribute the air. Instead, there are two components. Hence the term “split.” One part is inside the home, and the other is outside. If you have internal units in different rooms connected to an external compressor, it is referred to as a multi-mini split. Most homes in Mexico with air conditioning use a split system.

A split system relies on two components. The first part is the condenser that is usually located outside the home. The condenser is where the heat inside your house is expelled. The condensing unit houses the compressor. This part compresses the refrigerant. When the refrigerant is compressed, it changes from a gas to a liquid and heats up. There is a fan that blows outside air over a metal coil that contains the refrigerant. The fan cools the refrigerant. 

The compressor connects to the second component located inside the home. This part, called the evaporator, is mounted on a wall. The liquid refrigerant runs from the compressor to the inside unit through the evaporator coil. The fan in the indoor unit circulates the air from inside the room. As the air passes through the interior unit, the refrigerant absorbs the heat and recirculates it back into the room.

There are many reasons why split air conditioners are used more than central air conditioning units, especially in Mexico. Split air conditioners are very efficient and can easily be placed in many locations of a home. They are generally quieter than central air units. However, the most significant advantage is that split air conditioners tend to be easier and cheaper to fix and maintain.

Air conditioners are available in different cooling capacities. If you have a larger space to cool, you want an air conditioner with more cooling capacity. Until recently, BTUs were used to gauge the right size unit for each area. BTU stands for British Thermal Unit. The general rule of thumb was that for every square foot of space, 20 to 30 BTUs are needed to provide a comfortable environment.

New standards were established this year and will be mandatory by 2025. This new rating system is called SACC (Seasonally Adjusted Cooling Capacity). The rating will more accurately reflect cooling in a range of conditions, not specific situations, as the current BTU system does.

If you select an air conditioner with more BTUs, you will pay more for your electric bill, and you will waste unnecessary power. If you choose an air conditioner with fewer BTUs, you will also run up your electric bill. Since you will never feel cool, you will continually be running the machine on full power. If you have high ceilings, more people, or lots of sun, you may be best served with an AC unit at the higher BTU output. If you are in a well-shaded room, you might be better off with a unit at the lower recommended output.  

Air conditioning units are available today with additional features. Some have energy-saver options where the fan turns off when the thermostat turns off the compressor. You can get one with “check filter lights,” so you are reminded when to change or clean the filter. There are versions with sleep modes, timers and oscillating vents that will sweep the air evenly around the room.

Regardless of the system you choose, most units come with a manufacturer’s warranty of one to two years for parts and labor.

Sheryl Novak

Sheryl Novak is an expat Canadian who has owned a home in Mexico for over 10 years. She is the owner of SOLutions Mexico — the online furniture store for your home in Mexico. She is considered the expert on sourcing all styles of furniture, for all sizes of budgets, in Mexico.