There are a variety of factors you need to consider when installing a new air conditioning system to ensure that you get the right system for your house. This includes things like SEER ratings and how many speeds the compressor has. Even more critical is making sure that the system is the correct size for your house. Installing an undersized or oversized AC is a major waste of money and will lead to you encountering issues like higher energy bills, more frequent repairs and the system having a shorter lifespan. In this article, we’ll examine the various factors to consider when sizing an AC system and the process professionals use to accurately determine the optimal system size for a house.
Average Cooling Requirements Per Square Foot
There are general recommendations on the number of BTUs of cooling required per square foot for an AC system to operate effectively, and these recommendations are based on the local climate. The basic recommendation is that you need a minimum of 20 BTUs per square foot, but this doesn’t really apply in overly hot and humid places like southern Florida. In our area, you’re usually better off with at least 25 BTUs per square foot to ensure your AC system can still work effectively on the hottest, most humid days. The average home in Florida is around 1,7000 square feet, and a house this size would usually require around a 42,000-BTU AC system.
One important thing to note is that you also need to factor in ceiling height when estimating your cooling requirements, as the general recommendations are for houses with standard-height ceilings. If you have high ceilings, you’ll need a larger AC than you would for the same-sized house with standard ceilings. That’s just because high ceilings mean that there is a greater volume of air that the system needs to cool.
Understanding AC Tonnage
The size/cooling capacity of AC condenser units is measured in tons, and each AC ton is the equivalent of 12,000 BTUs. Residential AC units range in size from 1 to 5 tons (12,000 to 60,000 BTUs) and are available in half-ton increments. If you estimate your home’s cooling needs to be 42,000 BTUs, it means you’d want to choose at least a 3.5-ton AC. If your BTU requirements fall in between two sizes, you always want to round up and choose the larger of the two options. The fact that 5 tons is the largest residential AC unit available means that you will often need to install two units if you have a larger house.
How Professionals Size an AC System
Professional HVAC technicians use a specialized formula known as a Manual J load calculation, which allows them to size an AC system much more accurately than you could on your own. While the formula takes into account square footage and climate, numerous other factors can influence how hot a house gets and how large the AC system needs to be to keep it cool effectively. This includes things like the color of the roof, how much direct sunlight the house gets, the number of windows, skylights, exterior doors and building occupancy, among others.
If much of the house is shaded during the hottest part of the day, your cooling needs will be lower than they would be if your home is constantly in direct sunlight. Windows, skylights and exterior doors tend to be the biggest sources of heat gain. That means the more of them you have, the bigger your AC system needs to be. Specifically, the Manual J calculation factors in an additional 500 BTUs for every window, skylight and exterior door. It also states you need to add another 500 BTUs for every person living in the house.
Another essential factor is the age of the house. Older houses are typically less well-insulated and have more gaps in their exterior, allowing hot air to seep in from outside, resulting in them heating up faster. If you have a new house that’s properly insulated and mostly airtight, it will stay cooler and require less air conditioning capacity than an older home would.
KOZAK Air Conditioning & Refrigeration is the company to depend on for professional cooling services in the Naples, FL area. We offer expert AC installation services and carry equipment from industry-leading brands. Our process always starts with evaluating the house and assessing its cooling needs. From there, we’ll provide you with a range of options and a comprehensive quote, allowing you to select the best solution within your price range. We also install ductless mini-splits!
We pride ourselves on providing exceptional customer service and will ensure you receive a new AC system that meets your needs. To schedule a consultation or a service call, contact KOZAK Air Conditioning & Refrigeration today.
