The right size air conditioner depends on your home’s size, insulation, windows, sun exposure and airflow. A professional load calculation is the only reliable way to choose the correct unit.
An oversized air conditioner may cool your home quickly but won’t run long enough to remove as much humidity. The result can be a home that feels cool but damp.
What Determines the Right Size?
To recommend the size of air conditioner your home will need, Salmon Plumbing & Heating runs through a series of calculations. Factors that we consider are:
- The size of your home
- Number of windows
- Direction that windows are facing
If it is determined that your home requires a 2½ ton unit to meet design, you can choose anything between 2 ton and 3 ton and still meet code. The 2 ton unit will work fine on mild days, but will not keep up on design or over design days. If we have a stretch of weather over 30°C, or if you want to maintain an indoor temperature of 22°C, you should consider a 3 ton unit.
If your home’s calculated cooling load falls between two standard sizes, there may be advantages to selecting the larger unit. If you prefer cooler indoor temperatures during extended heat waves or your home receives a lot of afternoon sun, the additional capacity may provide greater comfort.
(Air conditioners are rated by their cooling capacity, measured in BTUs (British Thermal Units). HVAC contractors often describe cooling capacity in “tons,” where one ton equals 12,000 BTUs of cooling per hour. A higher BTU rating means the air conditioner can remove more heat from your home.)
There is a price difference when you move up to a higher capacity unit. The price differences are not that great when you consider that you will likely own your unit for 15 years plus.
Bigger isn't always Better
Too Small
- Runs Constantly
- Struggles on Hot Days
- Higher Energy Bills
- More Wear + Tear
Properly Sized
- More Comfortable
- Removes Humidity
- Energy Efficient
- Less Wear + Tear
Too Big
- Short Cycles
- Poor Humidity Control
- Less Energy Efficient
- More Expensive
What if My Air Conditioner isn't Keeping Up?
If you find your current equipment does not keep your home cool enough on very hot days, we have some recommendations:
- Keep your windows closed with your blinds drawn on sunny windows.
- Keep your unit running all the time, do not shut it down.
- Do not open windows on milder days. Your air conditioner is drying the air, which helps make you feel cooler. Opening windows allows humid air back into your home. This makes you feel warmer sooner as the temperature starts to rise again. It makes more work for your air conditioner when you turn it on again, since it has to remove the humidity from the air (again).
- Regular maintenance is required to ensure that your unit operates at maximum efficiency. A poorly maintained unit will not operate at the designed capacity, or run as efficiently.
Can an air conditioner be too large?
Yes. An oversized air conditioner cools the house quickly but doesn’t run long enough to remove humidity. This can leave your home feeling cool but damp while increasing wear on the equipment.
How Does my Furnace Affect my AC?
We have had customers that report their air conditioning worked better after they replaced their furnace. Your furnace fan also impacts your system performance. New furnaces have more efficient fans that move more air.
How Often should my AC be Serviced?
Have us out to maintain your furnace and air conditioner annually. Our technicians can tell you if it looks like you should consider replacing your equipment. If it’s time to look at new equipment, we will visit your house for a no-cost, no-obligation assessment of your home comfort needs.
A new furnace and air conditioner will keep you more comfortable and are more energy efficient than older units. New equipment carries worry-free warranties of up to 12 years.
