What is a Load Calculation? And Why Do I Need It?

What is a Load Calculation? And Why Do I Need It?

Load Calculation

You may be planning to get your heating and cooling system replaced. If you are like most customers, you may have a few questions about your project. One question in particular that we get from many of our customers is, “Is my system large enough to take care of my home?” The answer is, well, it depends. There are a lot of factors to properly size your heating and cooling equipment. This article will discuss the basics of a heat gain and heat loss calculation and why it is essential.

a man with a fan Belleville MI

Weather Conditions

Most areas of the world have distinct seasons, and to maintain comfort, businesses and homes alike have heating and cooling systems to offset the effects of the outside weather. The size or capacity of the equipment must be designed and selected to offset the outdoor weather conditions. For a heating and cooling system to operate optimally, it must offset the weather conditions at the proper rate. There are consequences if this is not done correctly. Many people think bigger is better. Even though this works in some areas, grossly oversizing heating and cooling equipment has some severe downfalls. For starters, the equipment will short cycle, which will lead to equipment damage. The increased wear and tear will set you up for large repair bills later down the road.


Additionally, you will not be comfortable. The system will satisfy the needs of the structure relatively quickly, even though you may not be physically comfortable. Heating and Cooling systems are designed to run, and grossly oversizing them will not help maintain comfort. To compensate for the lack of comfort, the end-user will continue to change the setpoint on the thermostat, which will compound the problem. For the trifecta of issues, grossly oversizing will lead to higher utility bills. A final disadvantage specifically to AC systems is that an oversized system will not remove the appropriate amounts of humidity from the structure.

Under sizing

Under sizing, the equipment does not work out too well either. The equipment will have extremely long run times, and energy consumption will increase. During the extreme parts of a heating and cooling season, the system will never keep up, and you will surely be uncomfortable. Excessive run times can also lead to premature equipment failure and hefty repair bills.

Just Right

To avoid trouble, a load calculation should be performed to properly size your heating and cooling system. A load calculation consists of measuring the physical attributes of your structure. We look specifically at things such as wall insulation, attic insulation, construction materials, etc. Additionally, the number of occupants, plants, animals, and appliances is also essential to correctly calculating heating and cooling loads. We even consider factors such as the building’s geological location, the building application, and how tight the building’s construction is. We take this information and input it into an energy modeling software. This software analyses the entered data and gives us the calculated equipment requirements for your heating and cooling system. Finally, we take this information and specify the equipment that will deliver the required comfort levels.

Modulating or Variable Stage Equipment

Heating and cooling systems are sized based on the average weather conditions that a geological region is expected to operate in. However, even a properly sized heating and cooling system will be oversized most of the time during its operating time. Hence, the industry trend is to get modulating or stage equipment that can operate partly loaded. Partly loaded operation for equipment provides the end-user with energy savings and increased comfort due to the equipment capacity closely matching the building’s required load for a particular point in time.

The Air Doctors Heating and Cooling, LLC Difference

Air Doctors Heating and Cooling, LLC are a fully licensed and insured heating and air conditioning company that serves most Southeast Michigan municipalities. Our staff is fully certified and pre-screened to provide our customers with a safe and satisfying experience. With over 100 years of combined industry experience, we take pride in solving all of your comfort needs. We are a family-based business that has been providing quality service to our neighbors for over 40 years. Contact us today to get started.