When you head to the grocery store to pick up lettuce for your family of four for dinner tonight, you don’t plan on purchasing a head of lettuce for each family member. That would be excessive and wasteful! The same concept applies when you purchase an HVAC unit. Buying too large of a unit as well as too small of a unit can be expensive and inefficient. Additionally, certain heating and cooling issues in your office or home could be related to having the wrong size HVAC.

Importance of Knowing Size of Air Conditioning Unit for Home
There are a large variety of HVAC equipment sizes and models and selecting the right one can be confusing. This is why qualified technicians conduct load calculations before outfitting spaces with HVAC systems. A load calculation takes into consideration the specifics of your home or office to guarantee you purchase the right size unit. If your HVAC is too small, it can overwork by attempting to heat areas that it was not designed to heat. This can strain the system and cause the unit to have a shorter life span while causing expensive bills. Having too large a HVAC system can mean that you overspend on initial purchase of the unit as well as your monthly bill will be higher than necessary to efficiently cool and heat your home. Oversized systems also are unable to properly dehumidify your home, leading to poor air quality. If your home is clammy and humid, it could be a sign that your HVAC is not the right size. The increased humidity levels of the air us a sign that your system is too large, as the unit cannot remove the latent heat in your home or office. When your system is too large, you might notice hot and cool spots throughout your home or office. If your system is too small, you may notice that you are unable to get the temperature of your home to stay consistent, and your home will difficult to cool on the warmest days of the year and heat during the winter.

How Do I Determine the Right Size HVAC for My Needs?
Knowing load calculation helps ensure that your home or office remains cool during summertime months and stays warm during winter. Load calculation measurements are performed by qualified technicians to determine what size HVAC unit would work best in your home. Historically, these load calculations were based upon guesses. An installer would look at the square footage of your home, and then suggest a unit that was much larger than necessary. Bigger is better was the assumption here. Often companies did this as it was better to err on the side of larger than smaller. Later, engineers stepped in offering paper, pen, and slide rule calculations to determine the load an HVAC could handle in your home. This method was incredibly time consuming.. After the Air Conditioning Contractors of America (ACCA) was formed over 40 years ago, a methodology using computer programs to calculate accurate load handling by an HVAC was created and is still used today.

A load is calculated using software perfected by the ACCA, and is referred to by experts as a Manual J HVAC load calculation. Data needed to perform the calculation includes types of windows in your home or office, area of all surfaces that lose or gain cool/hot air, insulation levels, orientation of the home, and other details. Once these numbers are entered in the program, the calculated output is the determining factor, in British Thermal Units (BTU) that your home needs per hour for each zone, room, and the house as a whole. From here, the measurement is used to select the equipment and design for duct work that your home or office needs. This will ensure that your space is generating the right amount of cool air, efficiently and accurately.

You can conduct measurements yourself to determine the size HVAC needed. Determining base BTUs will help, and in order to do that, start by calculating square footage. If you do not know this number, use a tape measure to determine length times width of the floor space, then multiply these numbers together. This is the square footage of the first room. Repeat this process for each room you are considering and then add these numbers together. The result is the entire square footage the HVAC will need to cover. The next step is to determine your base BTU calculation. To do this, multiply the square footage of your home by 25. If you have ceilings higher than 8 feet tall, multiply your number from the BTU calculation by 25%. This resulting number is the number of BTUs and assists with determining size of HVAC for your office or home.

Choose the Right Size HVAC in Knoxville, TN with City Heat and Air
The formula above is a great way to begin the selection process on a new HVAC selection process. It would be wise to confirm your measurements are correct by reaching out to a certified technician. Prices on HVAC units are not cheap, and it would be a terrible waste to purchase a unit poorly suited for your environment. Whether you are looking to update your existing unit, you are building a new home, or your environment is not cool enough for the rising summer heat, knowing what size unit you need can save you from purchasing the wrong size unit and from other problems. At City Heat and Air, we can save you the headache of calculations and the concern of choosing the wrong size HVAC. In fact, we have been doing this for over 50 years. Reach out today to speak with one of our certified technicians regarding your next HVAC purchase.