Air duct cleaning: when it is worth the money

Air duct cleaning is one of the most heavily marketed home services. Whether it is worth paying for depends on the condition of your ducts, not on a flyer in your mailbox.

The short version: for most homes, routine duct cleaning is not needed. Change your furnace filter regularly, and clean the ducts only after renovations, water damage, mould, pests or visible dirt.

What duct cleaning involves

A technician uses a powerful vacuum and brushes or air tools to loosen dust and debris from the supply and return ducts, vents and sometimes the furnace blower. A typical job takes a few hours.

When it can make sense

• After major renovations, when drywall dust and debris got into the system.
• After water damage or mould in or near the ducts.
• If there are pests, such as rodents or insects, in the ductwork.
• If vents are visibly clogged with dust or debris.
• When you move into a home that was neglected or had heavy smoking or pets.

When it is probably not needed

If the system is working well, airflow is normal and there are no signs of mould or pests, there is little evidence that cleaning improves your health or saves money. Dust in ducts does not necessarily end up in the air you breathe. Health Canada does not recommend routine cleaning for homes without a specific problem.

Cheaper steps that matter more

• Change or clean the furnace filter every one to three months, or as the manufacturer advises.
• Vacuum floor and wall vents, and keep them unblocked by furniture.
• Control humidity so that mould has nothing to grow on.
• Have the furnace serviced yearly.

How to avoid bad deals

Be careful with very low advertised prices, which often rise once the technician arrives, and with pressure to add sanitizers or coatings. Ask for a written quote, what is included and whether the company is insured. Ask to see the problem inside the ducts before agreeing to extra work. A reputable company will explain, not scare.

Example

You finish a basement renovation and notice drywall dust on the vents. Cleaning the ducts and replacing the filter afterwards is reasonable. A home with a clean filter and no problems after five years does not need it just because years have passed.

Prices vary by region and home size, so get a few quotes.

Sources: Health Canada: Indoor air quality.