How AC Works / Air Conditioning Basics
Air Conditioning Basics
What are the different efficiency ratings?
SEER (Seasonal Energy Efficiency Ratio)
- Measure of efficiency by which the cooling process is rated
- Represents the expected overall performance for a typical year's weather
- Higher SEER = Greater Efficiency = Greater Savings
- Applies to Conventional (Air Source) systems
- SEER ratings range from 13 to 23
- The SEER rating is shown on the EnergyGuide sticker which should be attached to the outside of a conventional system

EER (Energy Efficiency Ratio)
Measure of Efficiency of a Cooling System based on specific temperature levels
Generally calculated using a 95° outside temp
Higher EER = Greater Efficiency = Greater Savings
Applies to Geothermal (Ground Source) systems
Conventional Air Conditioning System
There are a range of efficient systems
- Select a SEER rating that works within your budget
- Any increase in SEER rating from your current system WILL save you money
How it works
A conventional system uses a system of:
- Ducts, Supply & Return Vents and Thermostats
- Indoor Air Handler
- Outdoor Compressor
The system uses outdoor air to remove heat & humidity from within house in hot weather
Or
Add heat to the house in cold weather
The Heat Pump
A Heat Pump works like an air conditioner, but it also has a heating mode
Liquid refrigerant is used to carry the heat
In hot weather, the heat pump removes hot air from inside the building and sends it outside
In heating mode, the refrigerant flow is reversed in order to get heat from the outside air to bring into the building.
The Split System
Inside and Outside Components
- The outdoor unit contains a compressor which controls the pressure applied to the refrigerant
- Also contains a condensor coil that converts the refrigerant from a gas to a liquid, and sends heat carried by the refrigerant outside.
- The Indoor Unit contains the Evaporator Coil
- This part cools and dehumidifies the air
- It converts the liquid refrigerant into a gas (or vice-versa)
- A blower motor then moves air over the coil to either heat or cool