Anyone with a forced air heating or cooling system in their home has air ducts throughout the residence. These are openings in each room of the house that lead downstairs to your furnace and also outside to the air conditioning unit if you have one. If air is being transported through your home through these ducts, it stands to reason that cleaning these ducts would make your breathing cleaner, right?
While duct cleaning makes sense when you have construction or other environmental contaminants and debris in your ducts, changing your home air filter regularly is a cheaper and easier way to keep the air clean in your home especially if you choose a high quality filter.
Let’s talk about the use of duct cleaning but also about the ongoing importance of replacing furnace filters regularly and their place in keeping the air that you breathe clean within your home.
Is duct cleaning necessary?
Duct cleaning involves a duct cleaning company using a powerful truck-operated vacuum connected to your furnace to suck dirt and debris out from your air ducts. Depending on how big your home is and how many ducts you have the entire process from start to finish including set up and tear down may take a 60 – 90 minutes, give or take.
Your furnace has a filter that you should change regularly as it helps to remove particles and dirt from the air. So in that regard, if you are already using a fresh, high quality furnace filter every 3 months or as instructed, you are already doing what you need to do to ensure that your air is clean and ducts are kept clean.
Duct cleaning: Two differing views
The National Air Duct Cleaner’s Association (NADCA
) claims that the average 6-room home produces around 40 lbs of dust each year through normal living. Much of that will (should) be removed through regular vacuuming and cleaning. They also suggest that dirty air ducts can increase energy costs, put more strain on your heating and cooling system and offer less healthy breathing inside the home.
The Environmental Protection Agency (EPA) refers to the fact that duct cleaning hasn’t been shown to prevent health problems nor have studies shown that dust in the ducts actually enters the air we breath. Dust often adheres to walls of the ducts and stays in place. It’s also likely that many other sources of dust and pollutants enter the air that have nothing to do with ducts ie. they enter through doors and windows, on clothing, from cooking, etc. Duct cleaning certainly doesn’t remove any of that and it’s already in the air and on the ground of the home.
Which stance is correct? Or are they both somewhat right?
How do I know if my air ducts need to be cleaned?
In all likelihood, they don’t. There are some times when having your ducts cleaned may make sense, however and even the EPA would agree. They are:
- New home: When a home is newly built, building debris and dust may be in the ducts and air returns. This is a great time to consider duct cleaning upon taking possession of the home.
- Renovations: After you’ve had messy renovations done in the home such as an additional room or hardwood flooring that may produce dust.
- Bad smell: If you smell something coming from the air returns or ducts themselves. It might be a dead animal.
- Mold: Mold and mildew in the air ducts or a musty, damp smell that won’t go away may require duct cleaning.
- Dirt: If you see evidence of dust or debris around the return air ducts, the ducts may be dirty to the point of needing to be cleaned.
- Illnesses: If you find that a member of your home is getting sick or suffers from allergies, a duct cleaning might be in order.
- Fire: If you have a fire in your home, it’s possible that soot and debris ended up in your ducts and air registers and should be removed.
We had ducts cleaned when an air return in the living room had a dead animal smell but the duct cleaners didn’t actually find evidence of a carcass in the cleaning bag when they finished the work. The smell disappeared after duct cleaning though so it’s possible the body had disintegrated because there was certainly something dead down there.
Is sanitizing air ducts worth it?
While air duct cleaning generally involves a powerful vacuuming of your air ducts and air return registers, some air duct cleaners additionally offer sanitizing and sterilization services as part of the duct cleaning regimen. Specifically, a chemical biocide or ozone application are often used inside the ducts to further clean and sterilize the duct work and to eliminate and prevent mold and fungus from growing.
Currently, the EPA refers to the little research that has been done on this subject. Specifically, they question the introduction of liquid chemicals into the ducts and the actual necessity to do so in the first place. Chemicals in your ducts can make it into the air you breath which might have an adverse effect on people in the home who are sensitive to chemical inhalation.
Unless your duct cleaning provider can provide proof of bacterial growth in your duct work, it’s probably better to avoid paying for this type of service and stick with regular duct cleaning if you’re having it done.
Is duct cleaning a waste of money?
An occasional duct cleaning due to a specific reason(s) mentioned above is likely not a waste of money and may be beneficial but is certainly not regarded as something to do regularly or without reason.
Ducts will get dirt in them, this is normal and expected. Dirt will often stick to the ducts and not actually leave. If the duct cleaning work is done incorrectly it may actually loosen the dirt and bring it into the rest of home after the cleaning, the exact opposite of what you want.
Issues can arise if you choose the wrong company to do the duct cleaning and they damage your furnace system. Often the company needs to cut an access hole in your furnace to install the vacuum and they may incorrectly seal this opening when the work is completed. They can also damage other parts of your HVAC system.
How often is duct cleaning necessary?
Unless you have any of the concerns or instances mentioned above, you might not need duct cleaning at all. It certainly isn’t something you need to schedule every year or anything close to that.
You’re better off vacuuming and cleaning your home regularly and spending money on a high quality furnace air filter. You can buy many expensive top brand air filters for one duct cleaning visit. More on air filters below.
How much should duct cleaning cost?
Duct cleaning is usually priced by the number of vents in your home to be cleaned. Expect to pay around $35/vent. For an average home you may pay $300 – $500 in total.
Be careful when considering cheap $199 duct cleaning offers or similar as it’s often a tactic to get the company in your door before they try to upsell you on more expensive cleaning options. They may suggest that you have mold or some other problem. For that low price, you can’t be sure it’s even a legit business. Mold is also something that must be diagnosed by a Certified Mold Inspector. Yes, you can eyeball mold and see it visually but even home inspectors are supposed to be certified to diagnose it as different types of mold exist.
You’re better off finding a reputable duct cleaning company with good online reviews. Find a company certified by a recognized body that is known in your local area or ask your network for a referral.
What should I look for when buying a furnace filter? Filter buying guide
Whether you choose to get duct cleaning done or not, you can make your home safer and cleaner by choosing a good quality air filter and replacing it regularly as per manufacturer instructions. Here are some tips in that regard:
Filter brand
There are plenty of air filter brands to choose from but the best brands in terms of quality include Honeywell, Filtrete, AIRx, Nordic Pure, FilterBuy, Rheem and Flanders.
Filter size
Check your furnace label for the correct filter size you require. You can also take the current filter out and check the size on it and assuming it is the correct size, replace is accordingly. The sizing for filters has three numbers representing the length x width x depth. Common sizes include 16″ x 20″ x 1″, 20″ x 25″ x 1″ and 16″ x 25″ x 1″. Filters are often cut nominally which means the actual filter size may be 1/2″ smaller to allow it to easily slide into the filter holder.
Ensure you pay attention to the air flow arrow and install the filter in the correct direction. How can you be sure? When your furnace is running, the filter will be pushed hard against the filter bracket in the direction of air flow. That’s how you can be sure you put the filter in correctly.
Pleated vs Non-pleated
Pleated air filters and the most common ones available. The filters are wavy so they’re easily distinguishable from non-pleated flat filters. Pleated air filters are generally regarded as more efficient and last longer than non-pleated ones. Pleated filters have more surface area due to the wavy design and thus are better able to catch contaminants and debris.
Fiberglass air filters
Non-pleated fiberglass air filters were the original ones widely sold. They are made with spun fiberglass and are flat rather than pleated. While they are safe to use, they have less surface area and tend not to trap as many particles as higher quality pleated filters. They also don’t last as long (perhaps only 1 month) so they need to be replaced more frequently.
Washable filters
Washable reusable electrostatic filters are just that: Filters that every few weeks can be removed from the furnace, washed out and then put back in again. It’s typically recommended that you use a garden hose to clean the filter by hosing it out on the clean side ie. on the side that is opposite of the filter’s air flow arrows to push the dirt back out in the opposite direction of which it entered the filter.
Filter MERV efficiency rating
MERV stands for Minimum Efficiency Reporting Value and represents a scale from 1 -20 where 20 is the best and highest rating and filters out the most and the smallest of particles. MERV 1 – 16 is generally used by residential and commercial customers whereas MERV 17 – 20 is generally used in applications requiring complete cleanliness such as surgical operating rooms and clean rooms. So the higher a filter’s MERV rating, the better the filter.
Having said that, you should follow your furnace manufacturer instructions as some furnaces may only accommodate a certain maximum MERV rating. Using the wrong one may damage your furnace in some cases. The higher the MERV rating, the greater the restriction of air flow. This means your furnace has to work harder to push air through the filter.
A regular house will normally use a MERV 10 rated air filter with success. If you have allergies, asthma, pets or a dusty environment, look for a filter with MERV 12 or greater assuming your furnace allows it.
Allergen air filters
Regular furnace filters actually exist to filter out dust and debris to protect the furnace, not you! Debris can clog and damage the furnace so regular air filters exist to protect the furnace. Some air filters from various manufacturers are specifically designed for allergy sufferers in mind. While regular paper air filters will trap dirt and dust, they don’t do a good job of removing smaller particles like mold spores, bacteria and various pollen, all of which we can breathe in.
A High Efficiency Particulate Filter (HEPA) with a decent MERV rating of 12+ can help to remove allergens that negatively impact allergy sufferers particularly during pollen season. Look for filters that meet your needs: Quality filters in the MERV 12 range list ratings on the packaging that specify their protection level against household dust, dust mite debris, lint, pollen, pet dander, smog, mold spores. The next level of filter at MERV 13 adds cough/sneeze debris and odor protection among others. The next level of filter at MERV 14 adds viruses, candle soot and car exhaust protection among others.
Replacement frequency
Check the manufacturer instructions but replacing your furnace filter once every 3 months is standard. If you remove the filter and it’s gray (filters are white when new) and looks like it’s wearing a fur coat, it’s time to change it.
Washable reusable filters will suggest the washing frequency. In my experience when you hose out a washable filter, the initial water that comes out is somewhat gray and goes clear when the filter is clean again.
Protecting against COVID-19
The best way to protect against a pandemic like COVID-19 in your home is to use a high quality furnace filter that is replaced regularly on schedule with at least MERV 13 rating if possible. This is according to the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).
You may also add portable air filters or cleaners within the home with HEPA or high MERV filters. Also control your humidity as this may reduce the transmission of some airborne pathogens. The ideal range usually quoted is 40% – 60% humidity.