Heat Pumps, Central Air, and Your Ducts: A Virginia Homeowner's Guide

One duct system, two seasons

NOAA describes Virginia's climate as humid, with very warm summers and moderately cold winters, and DOE's Building America guide places the state in its Mixed-Humid climate region. In EIA's 2020 survey, about 27% of Virginia homes heated mainly with a central heat pump and about 56% with a furnace, and about 83% used central air conditioning.

DOE notes that air-source heat pumps combine heating and cooling. In those homes, the same air handler, filter, and ducts are in use during both seasons.

Sources: NOAA NCEI, State Climate Summaries 2022: Virginia; U.S. DOE Building America / PNNL, Guide to Determining Climate Regions by County (2015); U.S. EIA, 2020 RECS: Highlights for space heating in U.S. homes by state; U.S. EIA, 2020 RECS: Highlights for air conditioning in U.S. homes by state; U.S. DOE Energy Saver, Consumer Guide to Home Heating and Cooling

Filters and registers come first

Most day-to-day duct care is simple and doesn't require a service visit.

• Clean or replace the filter monthly during seasons of peak use, as DOE recommends, or on the schedule your equipment manufacturer gives.
• Use the highest-efficiency filter your system's manufacturer recommends, as EPA advises.
• Keep air vents clean and unblocked; move furniture, rugs, and curtains off supply registers and return grilles.
• Note rooms that are hard to heat or cool; ENERGY STAR lists this among the signs of possible duct problems.

Sources: U.S. DOE Energy Saver, Consumer Guide to Home Heating and Cooling; U.S. EPA, Should You Have the Air Ducts in Your Home Cleaned?; ENERGY STAR, Duct Sealing

When duct cleaning is worth considering

EPA suggests considering duct cleaning when ducts are clogged with excessive amounts of dust and debris, infested with vermin, or show substantial visible mold growth inside hard-surface ducts. EPA does not recommend that ducts be cleaned routinely, only as needed, and it says duct cleaning has never been shown to actually prevent health problems.

EPA also says that before any cleaning, the causes of mold growth must be corrected or the problem will likely recur, and it calls controlling moisture the most effective way to prevent biological growth in ducts. We don't diagnose or remediate mold; if we see suspected growth, we'll point it out so you can consult a qualified specialist.

Source: U.S. EPA, Should You Have the Air Ducts in Your Home Cleaned?

What cleaning doesn't fix

ENERGY STAR estimates that in a typical house about 20 to 30 percent of the air moving through the duct system is lost to leaks, holes, and poorly connected ducts, and it recommends sealing with mastic or metal tape rather than duct tape. DOE advises checking for disconnected or crushed ductwork, which can keep warmed or cooled air from reaching its destination.

Leak sealing, duct repair, refrigerant work, and equipment service are jobs for an HVAC contractor. Duct cleaning removes dust and debris; it doesn't change how tight or well insulated the ducts are.

Sources: ENERGY STAR, Duct Sealing; U.S. DOE Energy Saver, Consumer Guide to Home Heating and Cooling