HVAC Placement: What Makes Space, Doesn't Always Make Sense - 4/26/2000 - House Systems HVAC Heating Air Conditioning

HVAC Placement: What Makes Space, Doesn't Always Make Sense

Builders often choose to place HVAC equipment and ductwork in crawlspaces, attics, and garages, since space is a premium for homebuyers. However, placing HVAC within the conditioned space instead can positively impact energy efficiency, comfort, and health.

New houses typically are insulated with R-15 to R-30 or more, but ductwork outside conditioned space usually has only R-4 to R-6 insulation. Ductwork and equipment cabinets are also often leaky, causing between 20 and 35 percent energy loss through air leakage and conduction in unconditioned space.

Potential benefits of conditioned space placement for HVAC include:

• Improved energy efficiency with utility costs reduced up to 35 percent, or $300 per year for a typical home
• Improved comfort due to better control of duct leakage and relative humidity
• Lower initial equipment costs because of downsized system heating and cooling capacities
• Reduced costs for duct insulation

If you install HVAC equipment outside conditioned spaces, consider the following precautions:

• Carefully follow manufacturer's directions for the installation of a gas furnace or heat pump for the climate area of the home.
• Keep ductwork below the insulation, where possible. If this placement is not possible, use duct insulation that is R-6 or better and tightly seal duct seams.
• Install a float switch in the auxiliary drain pan. If the pan fills with water, then the switch will shut off the unit.
• Make sure main and secondary drain lines are independent and protected from foot traffic.
• Make sure main and secondary drain lines are independent and protected from foot traffic.