7 Reasons HVAC Installation Must Include a Load Calculation

7 Reasons HVAC Installation Must Include a Load Calculation

A load calculation is an important part of the HVAC installation process. Before scheduling an AC installation or installing a new heater, your local contractor must determine the right-sized system for your home. This means they can choose one based on its square footage and other factors such as climate, the number of windows, insulation, and the structure’s orientation towards the sun. Below, we’ll examine what load is and why it’s important.

What Is Load?

An HVAC system’s load refers to how much heat energy it must remove or add. However, capacity refers to the unit’s cooling or heating power; the two are different. An HVAC unit’s load is expressed in tons. For example, a one-ton unit can remove 12,000 British Thermal Units (BTUs) of heat per hour. Residential ACs range from 1.5 to 5 tons.

A load calculation allows an installer to determine the best air conditioner, furnace, or heat pump suited for your building. Technicians perform a Manual J load calculation to size a system to optimize comfort and efficiency. Other calculations include Manual S for equipment selection and Manual D for duct design. 

Heating and cooling loads can be divided into the following categories:

  • Design Load Calculations: Factor in your home’s location and average temperatures for each season and month of the year.
  • Extreme Load Calculations: Consider only the hottest and coldest temperatures in your area; focusing solely on extreme loads can lead to oversizing a unit.
  • Part Loads: Consider average heating and cooling requirements for an average day since the bulk of a day is not at the highest or lowest temperature.

Manuals for calculating load are published by the Air Conditioning Contractors of America (ACCA). They are complex and require expertise to perform correctly.

Why You Need a Load Calculation

Here are seven reasons every HVAC installation should include a load calculation:

  1. Maintain a Comfortable Temperature
  2. Reduce Energy Consumption
  3. Lower Costs
  4. Identify Areas of Heat Loss and Heat Gain
  5. Control Humidity
  6. Improve Indoor Air Quality
  7. Comply with the Law

1. Maintain a Comfortable Temperature

Unless an AC or heating system is properly sized, it will struggle to maintain the temperature set on the thermostat. It may be unable to reach the set temperature at all. Even if it can, this will take much longer. A load calculation helps increase temperature accuracy so you’re more comfortable and parts of your home aren’t too warm or too cool.

2. Reduce Energy Consumption

A properly sized HVAC system uses less energy to maintain the desired temperature. While this can reduce your carbon footprint, you need a professional to perform the load calculation. Estimating an AC or heating unit’s size and trying to install it yourself can have unintended consequences. If something goes wrong, the system will require costly repairs, and missing any details means you won’t get the most from it.

3. Lower Costs

Not calculating load properly can result in inefficiencies and repairs that may cost more than hiring an HVAC installation professional in the first place. If a unit is too small, it’ll cycle more frequently, consuming more energy and wearing out faster. Corrosion, loose components, and mechanical failures may become more common. 

Poor planning can also result in a shorter equipment lifespan. Between higher energy bills, more frequent breakdowns and repairs, and early replacement, the cost of ownership will be higher. If the unit is too powerful, you’ll also see higher energy costs and increased wear. Therefore, a load calculation can make your investment more worthwhile.

4. Identify Areas of Heat Loss and Heat Gain

A contractor can find areas of heat loss and heat gain in your home. These are often found during a load calculation. Heat loss or gain can occur through window glass, gaps in the sides of windows, or spaces in walls and air ducts. Unless these gaps are closed and other issues addressed, even a new HVAC unit won’t be as efficient.

Additionally, a technician can calculate the load for your current system. Calculations have become more precise, and the equipment in place may have been improperly sized (never use your current system’s specifications to choose a new one). Resolving heat loss or gain can also change your home’s load requirements, so it pays to be as thorough as possible during HVAC installation.

5. Control Humidity

An HVAC system lowers relative humidity aside from controlling temperature. Too small an AC unit won’t remove enough moisture, so your home will feel warmer. Too large a system can remove too much humidity and make the air very dry. Therefore, the unit should have the correct load specifications, even if you install a whole-home humidifier or dehumidifier. 

6. Improve Indoor Air Quality

A load calculation can also lead to improvements in indoor air quality.  By addressing ventilation, airflow, and air leakage issues, an installer can take steps to improve your family’s comfort and health. Improved filtration and humidity control can also aid in improving air quality.  However, your HVAC system must be properly sized for these to be effective. 

7. Comply with the Law

State law may require HVAC professionals to perform load calculations for cooling or heating equipment. That’s because a load calculation can improve your safety. In Texas, heating and cooling appliances are required to be sized using the ACCA’s Manual S, Manual J, and other approved sizing methodologies.

Call Trilogy AC to Schedule HVAC Installation

At Trilogy AC, every HVAC installation begins with a load calculation. Our technicians are NATE-certified and can install any type or brand of AC or heating unit. They’re also familiar with the heating and cooling needs of Texas residents. To schedule an in-home evaluation and estimate, receive expert help with AC or heating installation, and learn about our membership plans and financing options, call (832) 979-9857 today.