You and your family depend on optimal air conditioner performance to keep your home cool throughout the year. When you pick the right AC unit size for your space, you can enjoy the benefits of a comfortable living environment, energy efficiency, extended equipment life span and cost savings.
Buying an AC unit is a significant long-term investment. By using this AC size guide for residential homes, you can make an educated purchasing decision that benefits your family and meets your home’s specific needs.
When it comes to choosing an AC unit size, it’s more about cooling capacity than physical size characteristics like length and width. British Thermal Units (BTUs) measure how much energy the air conditioner uses to remove heat, usually within an hour. Cooling capacity is also expressed in tonnage, with AC units ranging from 1.5 to 5 tons. One ton of cooling is equal to 12,000 BTUs per hour.
Knowing how many BTUs or which tonnage you need to cool your space will help you select the best air conditioner size for your home. The BTU rating you’ll need depends on various factors, such as the size of your house and how well it was constructed to maintain consistent indoor temperatures.
Your home’s square footage should be the first factor you consider when determining air conditioner size. It takes about 20 to 30 BTUs to cool 1 square foot, so you can multiply your home’s square footage by 20, 25 or 30 to determine an estimated BTU rating for cooling the entire space. However, keep in mind that many variables come into play when figuring out the right BTU for your home, so a simple calculation may not tell the full story.
Rectangular- and square-shaped rooms are easy to measure, while multidimensional or circular rooms can be a little more complex. When assessing your home’s square footage, you can exclude interior spaces that don’t need to be cooled, like hallways or sunrooms. Think about your home’s layout, such as how many stories it has or if you have an open floor plan, to determine if you need a system with more BTUs. Working with a professional can help you get the most accurate measurements.
In addition to square footage, you should also consider the climate you live in. Houses in a warm and humid climate will need more cooling throughout the year than homes with the same square footage would need in a colder climate. For homeowners throughout Florida and other southeastern states, look for an AC unit with a higher BTU rating to help reduce heat and humidity consistently throughout the day.
While considering environmental circumstances, you should also evaluate your home’s sun exposure. Do you have a lot of trees or shrubs near your property that shade your home from the sun? Do you have south- or west-facing rooms that get intense sunlight throughout the year? The more sunlight your house gets, the more AC power you’ll need to keep the space cool.
Most residential homes have a ceiling height of 8 feet, so AC units are generally designed to cool rooms based on that standard. If your home has higher ceilings, take that into account when selecting an air conditioner. You may need an AC unit with a higher BTU rating to help cool that extra space.
The better the insulation your home has, the better your AC unit can maintain consistent indoor temperatures. If your house has gaps in the attic, ceiling, walls, windows or doors, you may need a bigger air conditioner to keep your home comfortable throughout the year. Some building materials, such as brick, stone or concrete, are better at regulating temperatures than others.
To ensure the best performance, you may want to consider addressing air leaks in your home before deciding on an AC system. If your home has poor insulation, your unit could end up working harder and longer to reach ideal temperatures. Sealing your home against air leaks can bring long-term cost savings.
Your home’s doors and windows can significantly affect your home’s energy efficiency. The higher quality your doors and windows are, the better your AC unit can keep spaces cool with less energy. Using window treatments such as shades or drapes can help block sunlight and heat, helping your AC unit cool spaces more efficiently.
Picking the right AC unit for your home can depend on window and door characteristics such as:
People generate heat, so the more people who regularly occupy a space, the more BTUs you’ll need to keep your home cool. If more than two people regularly spend time in a room, you can add 600 BTUs for each additional occupant. Whether you have a large family or like to host, you may need a larger AC unit to ensure everyone remains comfortable throughout the day.
When contemplating air conditioner size, consider how people will use different spaces in the home. Gathering spaces will be warmer as more people come together. Kitchens will also be warmer, requiring as much as 4,000 more BTUs. Some appliances and electronics can generate heat, and features such as skylights and fireplaces can contribute to heat loss and gain.
If you’re planning to replace an existing central cooling system, make sure the ducts are properly sized for the new system. Undersized and oversized ductwork can lead to inefficient air flow and reduced efficiency.
A professional can assess your existing ductwork to ensure it’s the right size and arrangement for the AC unit’s cooling capacity. They can also check for and repair cracks or gaps that could reduce airflow efficiency, ensuring optimal system performance.
It’s possible to get a rough estimate of the AC size your home needs by measuring square footage and multiplying it by 20. For example, if your home is 2,100 square feet, you’d need an AC unit with at least a 42,000 BTU rating. You may need to add or subtract BTUs for factors like ceiling height, number of occupants, sun exposure, number of windows and insulation quality.
Performing these calculations on your own can help you get an idea of what you might need, but it’s not a comprehensive evaluation. A Manual J load calculation is required to get an accurate analysis of your home’s requirements. Through a Manual J calculation, an AC professional will evaluate all the important factors and give you the proper AC unit size for your home.
Another factor to consider when choosing AC size is the kind of maintenance the model will require. Regular maintenance is key to protecting equipment life span and ensuring optimal performance. If your AC unit is the wrong size for your home, it may experience unnecessary wear and tear from underperforming or overworking, leading to higher maintenance requirements and costs.
Most AC units require maintenance such as:
Choosing the wrong AC unit size can lead to increased costs, energy waste and premature system failure. Avoid these common mistakes when selecting an air conditioner to ensure you get the right size for your specific space.
An air conditioner that’s too small for your space will run constantly to maintain desired temperatures. Even though it runs often, it may fail to cool your home sufficiently and lead to uneven cooling throughout different rooms. The unit will quickly become overworked, all while raising your utility bills.
An oversized air conditioner is susceptible to short cycling. By reaching indoor temperatures too quickly, it’ll turn on and off frequently and cause excess wear and tear. It may have a shortened life span, consume more energy than needed and increase your energy costs.
AC units that are too large can also cause humidity levels to fluctuate. These oversized units may cool a space quickly, but they don’t run long enough to extract the humidity from the air. If humidity levels are too high, you could have increased risks of mold and mildew growth.
Failing to account for all the factors that affect your home’s interior temperature can lead to picking the wrong AC unit size. If you only rely on square footage, you may end up with a unit that doesn’t have enough cooling power. Climate, insulation quality, ceiling height, number of windows and number of occupants all affect indoor temperatures and play a role in determining an air conditioner size for your home.
While your budget is an important consideration, choosing an air conditioner based on the initial price alone can be a mistake. A cheaper unit may be too small for your home, leading to more spending in the long run through increased energy bills and a shortened equipment life span. Choosing a unit that matches your home’s specific needs will be a valuable investment.
AC units have a Seasonal Energy Efficiency Ratio (SEER), which describes their energy efficiency. While a higher SEER can indicate higher upfront costs, it also equates to greater energy efficiency and long-term savings.
The best way to determine the right size of air conditioner for your home is to consult with a cooling system expert. Purchasing an AC unit is a significant investment — you want to ensure you’re getting an air conditioner that will last your home for years. When you turn to professionals for help, you can trust them to educate and guide you in making the best decision for your space.
Professionals have extensive experience evaluating homes of all types and sizes. They thoroughly understand the important factors that affect indoor temperatures, and they know how to accurately assess your space to determine your specific needs. Local experts will also know the right AC unit size based on your climate.
When you consult with experts, they can recommend specific AC brands and models that meet your budget requirements and preferences. They can help you select a unit that optimizes efficiency, system life span and your family’s comfort. Professionals can also explain additional features, such as smart thermostats, to help you maximize your air conditioner investment.
When you need to replace your air conditioning system, turn to Strada Air Conditioning & Heating. Our expert technicians have extensive experience and training in evaluating your home’s unique cooling needs. We can assess your house and advise you on the right system capacity for your space and area — we have 41 locations throughout the Southeast, so we know what it takes to live comfortably in your local climate.
We also sell and service all major air conditioner brands, giving you the options you need to find the right size and model for your home. Once you’ve selected an air conditioner, you can trust our team to remove your old system and install your new one quickly and efficiently. We’ll test it to confirm it works properly and provide guidance on how to operate it so you can feel confident.
With the right air conditioning system for your home, you can enjoy energy efficiency and cost savings. Our optional 10-year warranty for new cooling and heating systems offers even greater peace of mind. Contact us today to learn what size AC you need to keep your home comfortable.
Joe Strada, owner of Strada Electric, Security & Air Conditioning, started working at the young age of 14. He’s never attended college, but he has spent his life dedicating his time and energy to his trade and providing high-quality services to his customers. At 19, Joe started working at a well-known air conditioning company and developing his commitment to excellence. He has state certifications in electric, plumbing, air conditioning, residential building and general contracting. During his years of training and experience, Joe noticed a sincere need for a dependable electrical contractor in Florida who embodied the same dedication to customer service in which he believed. In 2003, Joe co-founded Strada Electric, Security & Air Conditioning. Since then, the company has been in the business of providing peace of mind to customers. We offer expert electric, security and air conditioning solutions for homes and businesses, leveraging our experience to deliver professional and responsive service with reliability and respect.
