Intro to Load Calculations

December 29, 2016

You've probably heard the term "load calculation" used in reference to an HVAC system, but if you're like most homeowners, you may not know exactly what it means. Simply put, load calculations are the process HVAC contractors use to determine the equipment size (or capacity) needed to heat or cool a home.

How Accurate Load Calculations are Performed

In the past, it was a common practice for HVAC contractors to size new equipment using a rule of thumb that was roughly based on a home's square footage. Usually, the installer added some extra square footage to be on the safe side, so the equipment selected was often significantly oversized for the home.

Today, HVAC professionals have a much more accurate tool to help them size equipment: specialized Manual J software that's used to perform a detailed load calculation. The calculation is based on a number of factors, including unique home characteristics entered into the program, such as:

·       Climate region.

·       Square footage and orientation.

·       Insulation R-values.

·       Window sizes, types and location.

·       Air leakage rates.

·       The number of occupants.

·       Homeowner comfort preferences.

·       Lighting and major heat-generating appliances.

Benefits of Correctly Sizing HVAC Equipment

When your HVAC equipment is sized properly based on detailed Manual J load calculations, you can reap a number of benefits including:

Greater efficiency. Accurately-sized equipment is able to heat and cool your home more efficiently using less energy, so you'll save money on operating costs.

More consistent comfort. Equipment that's properly sized provides better temperature and humidity control, so you'll have fewer issues like hot and cold spots or an uncomfortably sticky living environment.

Longer lifespan. Installing HVAC equipment with the right capacity also helps prevent extra wear and tear caused by short cycling, which is a common occurrence with oversized equipment that shortens its service life.

Equipment cost savings. When your new equipment is sized correctly using detailed load calculations, you'll save money because smaller-capacity equipment is less expensive.

To learn more about the role that a load calculation plays in accurately sizing new HVAC equipment for your Des Moines home, contact us today Lozier Heating & Cooling.

Our goal is to help educate our customers in the greater Des Moines, Iowa area about energy and home comfort issues (specific to HVAC systems).

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