When the hot summer weather hits Ohio, many homeowners rely on a home air conditioning system to stay comfortable and safe. Whether you’re purchasing your very first AC unit or you need a replacement, sizing is imperative. Below, we’ll provide you with our best tips on how to size an air conditioning unit for your home appropriately.
Why Does Proper Sizing Matter?
When it comes to AC sizing, one of the most common questions homeowners have is why size really matters. There are a couple of different reasons why sizing is essential. If you get an air conditioning unit that’s too small for your home, it won’t consistently cool it. Your cooling system will run constantly, driving up your utility bills. Furthermore, the system won’t last as long due to the constant strain it will be under throughout the entire summer.
On the other end of the spectrum, getting an air conditioning unit that is too large is also problematic. Not only will it cost you more upfront to purchase, but you’re also more likely to experience poor humidity issues. This is because an oversized unit won’t run long enough to remove enough humidity from the air. Even if the thermostat shows a comfortable temperature, high humidity can make your home feel uncomfortable.
Additionally, oversized AC units will short-cycle, which can lead to premature wear and breakdown issues. The key to purchasing an air conditioning unit for your home is ensuring that it’s properly sized to meet your cooling needs. This will provide optimal indoor comfort and overall efficiency.
Understanding AC Sizing
Every air conditioner is built with a specific cooling capacity, which tells you how much heat it can remove from your home. This capacity is measured in British thermal units (BTUs), and most manufacturers also express it in tons. One ton equals 12,000 BTUs per hour, so a three-ton AC system can remove about 36,000 BTUs of heat from your home every hour.
One of the biggest misconceptions out there about proper AC sizing is that it’s based solely on the total square footage of your home. While your home’s size does play a big role in determining the proper size air conditioner, it’s just one of many factors. Some other key factors include your ceiling heights, insulation rating, sun exposure, regional climate, and window orientation.
Quick and Dirty Estimates
If you’re just trying to get a ballpark idea of what size air conditioning unit your home will need, there’s a simple rule you can use. Most HVAC professionals suggest 20 BTUs per square foot of your living space. This means if you have a 1,000-square-foot home, you’ll need a 1.5- to 2-ton air conditioning unit.
If your home is 2,000 square feet, consider going with a 2.5- to 3-ton AC unit. It’s important to know that this rough estimate doesn’t account for insulation, ceiling height, regional weather, and other key factors that can influence AC performance.
Manual J Calculation
When you call one of our professionals for AC installation, you can ensure you’re getting an air conditioning unit that is appropriately sized to meet your cooling demands. Our technicians use the Manual J load calculation to determine the appropriate cooling capacity for your new unit. This is a specific calculation that was developed by the Air Conditioning Contractors of America (ACCA) to ensure proper AC sizing. This calculation includes many key factors.
Square Footage
One of the most obvious factors that’s included in the Manual J load calculation is square footage. The larger your home is, the bigger air conditioning unit you’ll need to keep it nice and cold throughout the summer. Our technicians will add up your home’s square footage for each room of living space.
Ceiling Height
Ceiling height plays a major role in how effectively your air conditioner can cool your home. The higher the ceiling, the more air there is in the room that needs to be cooled. Because cool air naturally sinks and warm air rises, rooms with tall or vaulted ceilings tend to trap more warm air near the top. This requires a cooling system to work harder and run longer to maintain a comfortable temperature at floor level. For this reason, homes with high ceilings often need a system with greater cooling capacity. Our technicians take ceiling height into account when performing load calculations so that your system can cool efficiently without overworking.
Windows
Windows significantly impact how much cooling power your home needs. Older, single-pane windows allow more outdoor heat to enter and more conditioned air to escape. This increases the load on your air conditioner. Modern double-pane windows provide better insulation and reflect more sunlight, helping your home maintain a stable indoor temperature with less strain on your system.
The direction your windows face also matters. South-facing windows receive the most direct sunlight during the day, which can raise indoor temperatures and increase the amount of cooling required. East-facing windows let in morning heat, while north-facing windows typically contribute less to overall heat gain. During an AC installation, our technicians factor in window type, size, and orientation to ensure your system is properly sized.
Insulation
Insulation plays a critical role in determining how much cooling your home needs. It slows the transfer of heat between indoor and outdoor spaces, keeping cool air inside and hot air out. Each type of insulation is rated with an R-value, which measures its resistance to heat flow. The higher the R-value, the better it insulates. Homes with insulation that meets or exceeds local recommendations often require a smaller AC, as less cool air escapes. On the other hand, homes with poor or insufficient insulation require more cooling power to maintain comfortable indoor temperatures.
Ducting
One permanent component of your home air conditioning system you may not take into account, when it comes to sizing, is your ducting. However, it plays a big part in determining how much cool air makes it to the rooms throughout your home. If you have aging ductwork that has various leaks, you may lose up to 30% of your conditioned air. That means your air conditioning system needs to be larger to keep your home comfortable.
Internal Heat Gains
Internal heat gain is another important factor in determining the right size for your air conditioner. This includes heat produced by people, appliances, electronics, and lighting inside your home. Spaces like kitchens, home offices, or entertainment rooms generate extra heat that your AC needs to overcome. Even the type of lighting matters. Incandescent bulbs produce more heat than LEDs, which can increase your cooling requirements. Accounting for these internal heat sources ensures your system maintains a comfortable temperature throughout your home without overworking.
Reliable Air Conditioner Installation Service
Gene’s Refrigeration Heating & Air Conditioning, Plumbing & Electrical offers reliable air conditioner services for the Medina, OH area. Our HVAC technicians can also assist with all your air conditioner repair, replacement, and tune-up needs. Contact us today to schedule an appointment with one of our experienced technicians.
