With rising summer temperatures, more and more homeowners are considering air conditioning installation in Edmonton. As they start shopping for a new unit, there’s typically one question on their mind: What is the right size AC for my home?
Most online guides provide a general rule of thumb for AC sizing based on your home’s square footage. While it can be a useful starting point, a simple BTU-to-square-footage calculation isn’t enough. Much like furnace sizing, proper AC sizing relies on numerous factors like insulation, ductwork, local climate, and more. In this blog post, we’ll explain how air conditioner sizing works, what factors are important, and why partnering with an experienced HVAC professional is non-negotiable.
Understanding Air Conditioner Ratings
If you’ve been researching your new air conditioner online, you’ve probably encountered tons of technical jargon like BTUs, SEER, and cooling efficiency. While it might seem confusing, understanding these terms can actually help you in the long run. Let’s review some key definitions:
Cooling Efficiency (BTUs and Tons)
When it comes to sizing, the most important detail about your air conditioner is how much heat it can remove from your home. This is your system’s “cooling capacity” and is typically measured in BTUh (British Thermal Units per Hour) or tons. Here’s the important part: one ton is equal to 12,000 BTUs per hour. For example, a 3-ton air conditioner can remove about 36,000 BTUs of heat per hour. Residential air conditioners range from 1.5 to 5 tons.
Energy Efficiency (SEER and SEER2)
You may also encounter the terms SEER or SEER2 when researching air conditioners. These ratings measure energy efficiency, or how efficiently the system converts electricity into cooling.
SEER stands for Seasonal Energy Efficiency Ratio, and higher SEER ratings generally indicate a more energy-efficient system. In recent years, the HVAC industry has transitioned to a new standard, SEER2, which uses a stricter testing protocol.
While efficiency ratings are important when choosing a new air conditioner, they don’t determine the size of the system you need. Instead, SEER ratings can help you compare how much energy different AC units will use to cool your home.
How to Choose the Proper AC Size
If you search online, you’ll often see simple “rules of thumb” for central air conditioner sizing. According to these guidelines, choosing your AC size works like this:
- 1 ton of cooling capacity per 400–600 square feet.
While this conversion can sometimes give you a rough guideline, here is the important part: This rule of thumb is not a safe way to actually choose a central air conditioner for your Edmonton home.
Proper AC sizing depends on numerous factors beyond the square footage. For example, older Edmonton homes with leaky windows and dated insulation might need a more powerful model than a brand new, airtight townhome. An AC sizing calculator fails to account for these details.
Another factor that can impact your air conditioning installation is your home’s ductwork. In Edmonton, many homes have ductwork that was originally sized for heating systems, not modern central air conditioning. As such, these smaller ducts can only accommodate a certain amount of airflow. In other words, a square footage calculation could tell you that you need a 3‑ton air conditioner, but your existing ducts can only handle a 2–2.5 ton unit.
Why Professional Sizing is Important
If rules of thumb aren’t enough, what should you rely on instead? The answer is simple: proper capacity calculations performed by an HVAC expert who understands the homes and climate of Edmonton. Rather than guessing from a chart, a qualified contractor will look at your insulation levels, window size and orientation, air leakage, ductwork, and how you actually use the space. Then, they’ll use a recognized sizing method, like the CSA-F280 method recommended by Natural Resources Canada, to accurately calculate your home’s true cooling load.
Contact Weiss-Johnson for Air Conditioner Installation in Edmonton
If you’re unsure what size air conditioner your Edmonton home really needs, the best next step is a professional in‑home assessment. The team at Weiss‑Johnson can evaluate your home and ductwork, perform proper sizing calculations, and recommend air conditioning options that are the right fit for your space and budget. Contact us today to take the first step towards a cooler home!
