The HVAC industry describes the amount of conditioning homes need as heating and cooling loads. The load refers to the amount of work any system must do to keep the structure comfortable. HVAC professionals base the size of the systems they install on their capacity to satisfy three different kinds of loads.
The most influential load HVAC engineers consider is the design load of structures. This load includes the layout of the building, its overall energy efficiency and orientation to the sun. Homes that have adequate insulation, thermal windows and little air infiltration have lower design loads. Two-story homes have different conditioning loads than single-story homes.
The extreme load refers to the hottest and coldest temperatures any given place experiences. Unlike the design load, this load carries little weight when HVAC contractors calculate the size HVAC equipment needs to be. Extreme weather conditions seldom last long enough to have a measurable impact on the overall performance or comfort of a properly sized HVAC system.
The part load, combined with the design load, weighs heavily on calculating the heating and cooling loads in terms of its capacity, along with the type of system selected. In our region, humidity factors into the part load, and in the cooling mode, humidity makes a difference.
Humidity adds to the amount of work an air conditioner or heat pump has to do to cool the air. Besides calculating the cooling load for homes, HVAC pros use software tools to evaluate the suitability of a system to manage the latent heat load, which describes heat plus humidity. The sensible heat load is the air temperature only.
Florida has a high latent heat load. When upgrading your HVAC system, insist that the HVAC contractor calculate the heating and cooling load using software called Manual J for sizing it and Manual S to make the best system selection for the unique attributes of this climate.
To learn more about heating and cooling loads, contact Rinaldi’s Energy Solutions, providing outstanding HVAC services for Orlando area homeowners since 1969.
Our goal is to help educate our customers in Orlando, Florida and surrounding areas about energy and home comfort issues (specific to HVAC systems). For more information about heating and cooling loads and other HVAC topics, download our free Home Comfort Resource guide.
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