Air exchanger: A home maintenance guide

How do you clean or replace air exchanger filters?

Filters must be kept clean to allow proper air circulation. The type of filter varies depending on the unit and must be replaced regularly to ensure optimal performance.

Washable filters (metal)

• Remove the filters.
• Vacuum to remove dust.
• Wash with lukewarm water and mild soap.
• Rinse and allow to dry for 24 hours before reinstalling.

Non-washable filters (disposable)

Some disposable filters (cardboard, foam, charcoal, or pleated filters) must be replaced. Consult your unit’s owner’s manual to identify the correct type.

Don’t have the manual anymore?

• Measure the filter (width, length, thickness).
• Consult a specialist to choose the right model.

Important reminders

• Position the filter correctly in its frame; otherwise, air will bypass it around the edges.
• Reset your unit if it has a service indicator light.

How often should you maintain air exchanger filters?

Clean or replace filters every 3 months, especially in spring and fall. Do it more frequently if you:

• have pets (due to pet hair and dander);
• are doing renovation work;
• use a wood-burning stove;
• suffer from allergies or allergic reactions and want to improve indoor air quality; or
• live near a busy road, a dirt road, or an area with high levels of pollen or widespread wood heating.

Dirty or dusty grilles are often a sign that filters need attention. Don’t forget about filters installed on return air duct grilles.

Can I use vinegar to clean the filters?

No. Use mild soap instead to avoid damaging the filters over time.

How do you clean air exchanger grilles and air intakes?

Outdoor air intake

The surface of the outdoor air outlet can become blocked easily. Even a partial obstruction reduces the unit’s performance.

• Regularly remove leaves, grass clippings, snow, ice, and debris.
• Have it professionally cleaned every 6 years, or more frequently following major work.
• Take the opportunity to clean the outdoor air outlet at the same time.

Indoor air intake

• Regularly clean the intake grilles.
• Add a filter to the grille to limit dirt buildup in the ducts.
• Clean this filter frequently to avoid restricting airflow.
• Check with the manufacturer to confirm this option is compatible with your unit.

In the kitchen, the grille must trap cooking grease.

Return air duct grilles must also be maintained to protect the components of the air exchanger and maximize its performance.

How do you keep your air exchanger in good condition?

By cleaning the following components at least once a year:

• Heat recovery core
• Fan
• Drain pan and drainage duct

The air exchanger plays an important role in maintaining good indoor air quality. Maintaining the ventilation system also helps optimize comfort related to your heating system, especially in winter.

Cleaning the heat recovery core

A clean core improves the unit’s energy efficiency. Ideally, clean it in the fall, whether it is made of polypropylene (plastic) or aluminum:

• Carefully remove the core.
• Soak it in warm, soapy water.
• Avoid very hot water and harsh cleaning products.
• Drain and dry it thoroughly before reinstalling.

If you have an energy recovery ventilator (ERV), do not submerge it. Use a vacuum or compressed air instead.

Cleaning the fan

Use a vacuum to clean the fan. If dirt is difficult to remove, call in a specialized contractor. Improper handling or even slight pressure can throw the blades off balance.

Cleaning the drain pan and drain (drainage duct)

Follow these steps:

• Clean the pan and its walls with soapy water.
• Make sure water drains freely through the pipe.
• Add water to the drainage duct as needed.

Do the ducts need to be cleaned?

Yes, but with specialized equipment. Take the following into account:

• The number of occupants in the home.
• The presence of pets or smokers.
• Any recent renovation work.

Check the condition of the ducts by looking inside the unit or at the air diffusers. Flexible ducts that are overstretched must be replaced. Even with regular maintenance, certain signs may point to a problem.

What are the signs of a problem with your air exchanger?

Some indicators may suggest your air exchanger is not functioning properly:

• Listen for unusual noises: An off-balance fan or a motor that needs replacing.
• Watch for condensation in the ducts: An outlet issue or insufficient insulation.
• Pay attention to musty odours: Humidity that is not being properly expelled.
• Inspect for water leaks: Condensation caused by a cold spot in the duct.

If you notice one or more of these signs, check your unit’s operation or call in a specialist.

How do you check air balance?

To ensure good indoor air quality, an air exchanger must bring in and expel the same amount of air.

• Too much pressure → moisture in the walls → mould
• Too little pressure → polluted air or gases being drawn back into the home

Simple bag air test

• Place a bag over the outdoor outlet of the air exchanger.
• Measure the time it takes to fill with air.
• Do the same at the air intake (supply vent).
• Time how long it takes to completely deflate.
• Compare the two times.

If there is a significant difference, consult an HVAC and ventilation specialist. Pricing varies depending on the tools and techniques used. You are not obligated to accept all additional treatments that may be proposed.

What are the right humidity settings to avoid frost in winter?

In winter, aim for 30% to 40% humidity to prevent frost. For more information, read our tip on ideal home humidity levels in summer and winter.

Regular air exchanger maintenance helps maintain good air quality and prevents humidity problems or mould. If in doubt, or if certain components appear to be faulty, it is best to have the unit inspected by a specialist. A timely inspection can prevent more costly repairs down the road.

FAQ – Air exchanger

1. How often should an air exchanger be maintained?

Filters should be cleaned or replaced every 3 months. A more thorough maintenance of the unit is recommended at least once a year.

2. How do you know if an air exchanger is working properly?

A properly functioning unit makes no unusual noises, produces no odours, and does not cause excessive condensation. Pressure or humidity fluctuations may indicate a problem.

3. Can filters be cleaned with vinegar?

No. It is best to use mild soap to avoid damaging the filters over time.

4. Is it necessary to clean the ducts?

Yes, but with specialized equipment. How often depends on factors such as the environment, the number of occupants, and the presence of pets or recent renovation work.

_{With thanks to FixAC, a member of CAA-Quebec’s network of Approved Residential Suppliers, for their contribution to this article.}