Duct Cleaning in an Older Pennsylvania Home: What to Check First

Why older homes deserve a closer look

Census Bureau survey data put Pennsylvania's median year built at 1966, fifteen years older than the national median of 1981, and about one in four Pennsylvania homes was built in 1939 or earlier. In a house that old, the ductwork there today may have been added, extended, or replaced over the years.

That history is why a quick look at your system before cleaning is worthwhile: it shows what's there, how to reach it, and whether anything should be left undisturbed.

Sources: U.S. Census Bureau: ACS 2024 1-year, Table B25035 (Median Year Structure Built); U.S. Census Bureau: ACS 2024 1-year, Table B25034 (Year Structure Built)

Start by identifying what you have

In the 2020 Residential Energy Consumption Survey, about 19% of Pennsylvania homes used a steam or hot-water boiler as their main heating equipment, compared with 8% nationally, and about 54% used central air conditioning. A boiler home may have no heating ducts at all, while its central air, if it has any, may run on separate ductwork.

• Main heating equipment: furnace, boiler, or heat pump.
• Cooling: central air, window units, or ductless units.
• Where the ducts run: basement, attic, walls, or finished ceilings.
• Roughly how many supply registers and return grilles the home has.
• Any past renovations that moved or added ductwork.

Sources: 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

Old insulation, tape, and register boots

EPA's duct cleaning guidance says to inspect the system before cleaning to be sure there are no asbestos-containing materials, such as insulation or register boots, in the heating and cooling system, and that such materials should not be disturbed or removed except by specially trained and equipped contractors. EPA's asbestos pages list oil and coal furnaces and door gaskets, and hot water and steam pipes covered with an asbestos blanket or tape, among the places asbestos may be found.

EPA also notes that asbestos-containing material in good condition that won't be disturbed generally won't release fibers, and that samples should be taken by a trained and accredited asbestos professional rather than by the homeowner. Pennsylvania's Department of Labor & Industry states that individuals who perform asbestos removal must work for a contractor holding current certification from the department.

• Don't sand, scrape, or tear suspect wrap, tape, or insulation.
• Mention any old-looking duct insulation when you request an estimate.
• If testing is needed, use a trained and accredited asbestos professional.

Sources: U.S. EPA: Should You Have the Air Ducts in Your Home Cleaned?; U.S. EPA: Learn About Asbestos; U.S. EPA: Protect Your Family from Exposures to Asbestos; Pennsylvania Department of Labor & Industry: Asbestos Occupations

Rowhomes, finished basements, and access

About 19% of Pennsylvania housing units are one-unit attached homes such as rowhomes, compared with about 6% nationally. In attached and older homes, ducts can be tucked into narrow chases or behind finished ceilings, so access can matter as much as square footage in how long a visit takes.

EPA's list of what to expect from a duct cleaning service provider includes protecting the ductwork and sealing and re-insulating any access holes so they are airtight.

Sources: U.S. Census Bureau: ACS 2024 1-year, Table B25024 (Units in Structure); U.S. EPA: Should You Have the Air Ducts in Your Home Cleaned?

What cleaning will and won't do

EPA does not recommend routine duct cleaning, only cleaning as needed, and notes that duct cleaning has never been shown to prevent health problems. Much of the dirt in ducts sticks to duct surfaces and does not necessarily enter the living space. EPA also reports little evidence that cleaning only the ducts improves a system's efficiency.

Cleaning removes accumulated dust and debris from the parts in scope. It does not include asbestos testing or removal, mold diagnosis or remediation, routine chemical treatments, or repairs to the heating system.

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