How Manuals J and D Help You Get the Right Size HVAC
When HVAC professionals size the cooling and heating system for your home, they use software called Manuals J and D. These software applications eliminate the guesswork involved with HVAC sizing. Manual J covers the size of the equipment, while Manual D addresses the ductwork design and its capacity. The longevity of the system, your energy bills and comfort are driven by the correct size for both.Manual J takes into account the conditioning load of your home, which includes these factors:
Cubic footage
Floorplan layout
Number of windows, their orientation to the sun and efficiency
Insulation levels in the walls and attic
Air infiltration levels
Heat-producing appliances and your lighting types
Preferred indoor temperatures
Number of household members and their ages
Landscaping factors.
Once the contractor completes Manual J, he or she moves onto Manual D to determine the ductwork configuration and size you need. The layout of your home makes a difference in ductwork design, especially if you have an open floorplan or high ceilings. Another benefit of starting the HVAC replacement process with the load calculation using Manual J is seeing how improving insulation levels and sealing air leaks would lower the size of the HVAC system you need.Using Manuals J and D eliminates the risk of installing too large or small a system. When they're too small, they won't be able to keep up with the conditioning load during weather extremes. Systems that are too large short-cycle, which means they run for short periods more frequently.Short-cycling causes higher energy bills and more wear and tear on the system. During the summer, air conditioners that run for brief periods won't remove as much humidity or airborne particulates, like pollen, dust and pet dander. In the winter, the heating system won't run long enough to thoroughly warm solid objects in your home, which causes the furnace to turn on more frequently.If you're searching for a new HVAC system and would like to learn more about Manuals J and D, contact Air Assurance. We've provided HVAC services in the Broken Arrow and Tulsa areas since 1985.Our goal is to help educate our customers in the Tulsa and Broken Arrow, Oklahoma area about energy and home comfort issues (specific to HVAC systems). Image courtesy of Shutterstock