What to Look for When Choosing an Air Conditioner in Alberta

Don't let summer weather get you hot-headed! Our guide to choosing an air conditioner in Alberta will help you stay cool when the weather gets warm - and without your bottom line turning red.

How an Air Conditioner Works

An air conditioner cools and reduces the humidity in in a room by the process of refrigeration. Air conditioners contain fluids that absorb heat when they evaporate and release heat when they condense. These fluids evaporate when hot air from the room (which is brought into the air conditioner by its fans) passes over coils filled with the fluids. In order to reconvert the refrigerants back to a liquid, the gas is compressed at high pressure, which releases heat that is passed outside by a fan. As the gas cools it converts back to a liquid, allowing the cooling process to continue.

Types of Air Conditioners

There are several different types of air conditioners, but the most common types include:

Window Air Conditioner: also known as a "unitary" air conditioner, this type of air conditioning system is compact and small enough to fit into a window. It ejects cold air at one end and releases heat at the other. Window air conditioners are best when all you need is to cool a room or specific area. These are the most common type of air conditioner, as they are quite affordable and easy to install.

Portable Air Conditioner: portable air conditioners can be placed on the floor of a room and release heat through a hose vent that goes through an exterior wall. A portable air conditioner is also useful when you only need to cool one room, though can be a bit noisier than other types of air conditioning units.

Split Systems: these are used for larger areas, such as an entire house. In the split system the condensation and evaporation functions of the air conditioning unit are split. Central air conditioning is one example of a split air conditioning system. It is usually combined with the furnace system, so that cool air is blown through the ducts. Central air conditioning is best when you want to have your entire home cooled, though it means that you have less control over the temperature of each room individually. 

Mini Split (ductless) Systems: a mini split system air conditioner can cool one or two rooms of a building. These are useful for homes without ductworks and have high energy efficiency, though they are considerably more expensive than window air conditioners.

How to Choose an Air Conditioner

Size and Air Conditioner Type

The first step in choosing an air conditioning unit is to decide what type is best suited to your needs. As stated earlier, window air conditioners are the most common, as they are relatively cheap and easy to install. However, you should make your decision based on what size of area you want to have cooled. If you just want to cool one or two rooms of your house, a window or portable air conditioner should be sufficient. If you want to have air conditioning for your entire house, you may want to consider installing a central air conditioning system, or a mini-split one. 

Size and Air Conditioner Capacity

Your next step in choosing an air conditioner is to determine what size of cooling capacity you need. An air conditioner's cooling capacity is typically expressed in British Thermal Units (Btu). One Btu is equivalent to the amount of heat needed to raise one pound of water by one degree Fahrenheit. Ratings for air conditioners typically range from 5000 to 20 000 Btu. To determine what Btu capacity you need, you will first need to know the square footage of the area you would like cooled. Then, refer to the table below for the capacity needed that corresponds to the size of the area you would like to cool:

Source: Energystar.gov

Adjustments

If the area that you would like to have cooled is very sunny, increase capacity by 10%. If it is heavily shaded, reduce capacity by 10%. Add 600 Btus for every additional person over two who regularly occupy the room. Increase by 4000 Btu if the area is a kitchen. 

Efficiency

An air conditioner's efficiency is measured by its Energy Efficiency Ratio (EER), which is the ratio of the cooling capacity to its wattage. The EER should be marked somewhere on the air conditioning unit. The higher the EER, the more effient the air conditioning unit is. Air conditioning units with an ENERGY STAR rating have achived the highest EERs on the market. Though they may be slightly more expensive to purchase, an air conditioning unit with a higher EER rating will mean reduced operating costs in the long run. 

How to Calculate How Much Energy Your Air Conditioner Uses

To calculate how much energy your air conditioning unit consumes when it is running, first divide its cooling capacity by its EER. This will give you the watt hour (Wh) per hour consumption. For example, if you have an air conditioning unit with 8000 Btu capacity and an EER rating of 10, it consumes 800 Wh per hour, or 0.8 kWh per hour.

How Much Does it Cost to Run Your Air Conditioning Unit?

Multiply the kWh per hour consumption by the number by number of hours that your unit runs per day. This will give you the daily electricity usage in kilowatt hours per day. For example, the above 8000 Btu unit that consumes electricity at a rate of 0.8 kWh per hour will use 8 kWh electricity per day if you use it for 10 hours a day.

To find out how much it costs to run your a/c unit, simply multiply the daily kilowatt hours usage by the electricity rate that you pay. For example, if your electricity costs 20 cents per kWh, and you use 8 kWh electricity in a day to run your a/c unit, it costs you about $1.60 per day to run. In a month this would be about $48.

Central Air Conditioning Systems

Central air conditioning systems are subject to minimum efficiency standards under Canada's Energy Efficiency Regulations. Under these regulations, central air conditioning systems must achieve minimum ratings of 12.0 to 13.0 for the minimum seasonal energy efficiency ratio (SEER). Like the EER, the SEER indicates the relative amount of energy needed to provide a specific cooling output under standard conditions, but takes into account annual consumption.

Calculate Your Annual Energy Consumption

Natural Resources Canada provides the following formulae for calculating the annual energy consumption for air conditioning:

Central Air Conditioning System
Cost of operation = (24 x DDc·18 / TOD - 18) x (CAP (35°C) / SEER) x (Cost/kW/1000)
Where DDc·18 = number of cooling degree-days (base 18°C)
TOD = summer outdoor design temperature (°C) for location
CAP (35°C) = the capacity of the air conditioner (in Btu/h) at an entering air temperature of 35°C
SEER = the rated seasonal energy efficiency ratio (Btu/h/W)
EER = the rated energy efficiency ratio
Cost per kWh = local electricity cost (in $/kWh)

Room Air Conditioning Unit
Cost of operation = (24 x DDc·18 / TOD - 18) x (CAP (35°C) / 0.9 EER) x (Cost/kW/1000)
Where DDc·18 = number of cooling degree-days (base 18°C)
TOD = summer outdoor design temperature (°C) for location
CAP (35°C) = the capacity of the air conditioner (in Btu/h) at an entering air temperature of 35°C
SEER = the rated seasonal energy efficiency ratio (Btu/h/W)
EER = the rated energy efficiency ratio
Cost per kWh = local electricity cost (in $/kWh)

How to Save Money on Your Air Conditioner

Air conditioners are powerful machines, and should be used wisely. While an air conditioner is not likely to hurt you physically, inefficient use of air conditioners can have harmful effects on your wallet! Here are some tips to keep your energy costs to a minimum while benefiting from the comfort of air conditioning

 Make sure that your air conditioning unit is correctly sized. Choosing a unit with a capacity that is too small or too big for the desired size will mean that it won't be able to work as efficiently as it should; a too-large unit will cycle on and off, and one that is too small will not be able to handle particularly hot days.

 Choose the highest EER rating possible. Though ENERGY STAR-rated products may come with a slight premium, their reduced operating costs will make them cheaper in the long run.

 Think about where you are going to install your unit. Try to locate it on the north-facing wall or on a wall that is shaded.

 Set the air conditioning unit to the highest temperature that is comfortable. Natural Resources Canada recommends 25^oC. If the space is going to be unoccupied for more than four hours, 28^oC is recommended.

 Make sure to clean the filters regularly to keep them free from dust and debris

You can also save on the operating costs of your air conditioning unit by taking a look at how much you pay for your energy. In Alberta you have a choice of energy supplier. It may be worth your while to shop around and see how the different retailers in your area compare - you might be able to find a good deal!