How Air Conditioning Works In A House

Jun 15, 2018 | Air Conditioning, Blog

When summer’s here, it’s hard not to be thankful that air conditioning exists. It’s magic how it turns the worst summer days into bearable ones. It really makes me wonder how air conditioning works in a house.

Well, you’ve heard it here first. It might seem as if it’s black magic wizardry, but air-conditioners aren’t actually magic. It’s science. (Wait, really?!) Air-conditioners are machines made-up of parts that cooperate with each other to achieve a result. And today, we’re going to take that machine apart and talk about the inner workings of how it works.


How Air Conditioning Works In A House


Exploiting Thermodynamics

Basically, air conditioning works because it takes advantage of the Gay-Lussac’s Law of Pressure-Temperature.

(Woah there, slow down! The what now?)

Okay, let’s not make this blog post confusing by adding too much science jargons into it.

Gay-Lussac’s Law says that high pressure means high temperature and high temperature means high pressure. So how does that factor in our air conditioning system?

When you compress normal room temperature air, it becomes hot pressurized air. While you keep it compressed, you let it cool back down to room temperature. But remember, it still has high pressure. When you decompress the pressurized room temperature air, it becomes cooler than room temperature. And that’s how you get cool air. (Yeah, Science!)


Cooling Process in Air-Conditioning

How does it actually work in an air-conditioning unit? Instead of normal air, the process makes use of refrigerants.

In previous air-conditioning models, we have used R-22 (or Freon® 22). But today, Puron® is approved by the EPA to replace R-22 as a much more sustainable option. You’ll see these in the air-conditioners we offer.

We use the exact same process, but it’s a cycle now. We have Compression, Condensation, Expansion, and Evaporation — and it goes full circle.



The compression is the first step of the cooling process. The refrigerant in gas form is at room temperature. The refrigerant enters the compressor — the heart of the air conditioning unit. The compressor squeezes the gas, increasing its pressure. As it increases pressure, it also increases in temperature.

The compressor is dubbed as the heart of the air conditioning unit. That’s because it pumps the refrigerant around the unit. It gives the refrigerant enough mobility to keep moving throughout the rest of the cycle.



The condensation is the second step of the cooling process. The refrigerant in gas form is now pressurized and hot. The refrigerant enters the condenser coil, a metal tube designed to lengthen the refrigerant’s travel distance. The condenser coil gives the hot gas enough time to cool down. As the refrigerant cools down, it turns into a liquid form because the boiling point of refrigerants is so low. That’s why it’s called a condenser.

The condenser coil is located outdoors. The air outside cools down the refrigerant with the assistance of the condenser fan. It works because the refrigerant at this point is hotter than the air outside, even if it’s hot outside — much like how hot coffee still cools down even on a hot summer day. This is why the outdoor units or the back of the window-type air conditioners are hot. Condenser coils are also built with condenser fins to allow for much faster heat exchange.



The expansion is the third step of the cooling process. The refrigerant in liquid form is now at room temperature, but it’s still pressurized. The refrigerant moves through the expansion valve. The expansion valve limits the flow of the liquid refrigerant, causing it to lose pressure. As it drops in pressure, it also drops in temperature. At this point, the refrigerant is now at its coolest point.



The last step of the cooling process is called evaporation. The refrigerant is in liquid form, cold, and unpressurized. It moves through the evaporator coil, a metal tube much like the condenser coil.

A fan sucks the air from your room. The air blows past the evaporator coil filled with the cold refrigerant. The cold evaporator coil absorbs the heat out of the air, cooling it down. The fan blows the cool air right back inside your home. And that’s how you defeat the summer heat.

As the cold refrigerant absorbs the heat, it returns back to gas form at room temperature. This goes back to the compressor, starting the cycle over again.

This is how air conditioning works in a house, whether it’s window-type or central air conditioning. It uses the same principles and processes.


Knowing This Will Help You In The Future

Now that we’ve demystified air conditioners, you might begin to understand your HVAC technician when he tells you that the condenser fan stopped working (and why that’s bad!) But remember, don’t fix anything yourself. Always seek professional help with delicate machinery like your air-conditioner!