Air quality is a huge factor in you and your family’s health. With most Americans spending the majority of their time indoors, indoor air quality (IAQ) is an enormously important consideration. You want to be able to protect yourself and your loved ones from the worst effects of exposure to outdoor pollutants, and the windows you have in your home are a major part of your home’s protection.
What are the risks of poor indoor air quality? How do windows affect IAQ? What other steps should you take to improve air quality in your home?
The Potential Hazards of Low Indoor Air Quality
The specific hazards associated with low indoor air quality can vary depending on the specific pollutants involved. However, some short and long-term health impacts noted by organizations like Johns Hopkins Medicine include:
- Coughing/wheezing
- More frequent/severe asthma attacks
- Irritation of the eyes and throat
- Chest discomfort (burning sensations)
- Reduced lung function
- Chronic Obstructive Pulmonary Disease (COPD) or emphysema
- Breast cancer
- Non-Hodgkin lymphoma
- Lung cancer
- Chronic inflammation & cardiovascular disease
- Heart attack
According to the National Institute of Environmental Health Sciences (NIH), “Air pollution, in all forms, is responsible for more than 6.5 million deaths each year globally.”
Who’s at the Most Risk from Poor Indoor Air Quality?
So, who is at the most risk of what the medical professionals call “adverse health effects” when indoor air is poor quality? The people most at risk include:
- Children (particularly infants)
- Adults over the age of 65
- Anyone with asthma
- Pregnant women
- Anyone with other respiratory conditions (lung disease, COPD, emphysema, etc.)
- People with heart disease
Children, in particular, are vulnerable to neurological conditions following prolonged exposure to severe air pollution over a long period of time (Source: John Hopkins Medicine).
Top Air Quality Hazards to Avoid
The big air quality risks can be divided into environmental, biological, and chemical categories.
- Environmental Air Quality Factors: This includes things like humidity (which can promote mold and mildew growth in the home) as well as ‘stale air’ and high carbon dioxide levels. When a home is kept sealed, air can actually stagnate and carbon dioxide accumulates faster than fresh oxygen can be cycled into the home.
- Biological Air Quality Factors: This includes things like pollen and other common animal-borne allergens (like animal fur or dandruff) which can cause an allergic reaction or trigger an asthma attack.
- Chemical Contamination Air Quality Factors. Many man-made sources of air pollution fall in this category, which includes smoke, smog, paint fumes, certain cleaning solutions, and more. In high concentrations, some chemical compounds can cause long-term harm.
What Role Do Windows Play in Managing Indoor Air Quality?
Windows (and doors) play an enormous role in helping you control your home’s indoor air quality. Every window or door with a National Fenestration Rating Council (NFRC) label will have a rating for something called ‘air leakage.’
This is a measurement of the rate at which air will flow through a window or door when it’s shut, expressed in cubic feet per minute per square foot of window. For example, if a window has an air leakage rating of 0.25 cfm/ft2, then a window with a total area of four square feet would leak 1 cubic foot of air per minute.
The smaller the number for the air leakage value, the less air can pass through the closed window or door. A low air leakage value is great for promoting energy efficiency and keeping your home cool when it’s hot out or warm when it’s cold out. This has led some to question if too tight a seal can be bad for your health.
Can a Too Tight Seal Really Pose an Air Quality Hazard?
In the previous section, we mentioned several external environmental factors and pollutants that can cause poor IAQ. Blocking these pollutants from getting into your home is good for maintaining a high indoor air quality.
However, keeping your home near-hermetically-sealed can mean that not enough oxygen passes into your home to replace the air you breathe, leading to a buildup of CO2 that is harmful.
Important note: it takes a long time for a single adult to cause enough of an increase in carbon dioxide to reach unsafe levels. The average adult exhales about a kilogram of CO2 per day (Source: BBC Science Focus), or about 41.6 grams per hour. A kilogram of carbon dioxide takes up about 0.547 cubic meters (1.7 cubic feet) of space at room temperature. So, an hour’s worth of CO2 would be about 0.023 cubic meters (rounding up).
The average bedroom’s dimensions are about 132 square feet, or 40.2 meters, with a ceiling height of 8 ft (2.43 cubic meters), for a total of 1,056 cubic feet (321.86 cubic meters). Carbon dioxide is considered dangerous once it exceeds 1,000 parts per million (ppm) of indoor air.
An hour’s worth of a single adult’s exhalations would increase the ambient CO2 by about 1/13,994, or 74.1 ppm. In a perfectly-sealed room, to get to unsafe levels (assuming a baseline of 400 ppm to start with), it would take a little over 8 hours to get past 1,000 ppm of carbon dioxide.
Meanwhile, in reality, even an incredibly well-sealing window or door might have an air leakage rating between 0.2 cfm/ft2 and 0.3 cfm/ft2. That’s between 12 and 18 cubic feet of air being transferred per square foot of window or door in the room per hour. Far more than enough to offset the 1.7 cubic feet of carbon dioxide a single adult breathes in or out.
So, while it’s technically possible, it’s highly unlikely that keeping your windows shut will be a significant IAQ risk… so long as human CO2 emissions are the only emissions you have to worry about, and not too many people are all occupying the same room for prolonged periods of time.
This isn’t even accounting for the air moved into a room by your HVAC system.
Unless your windows are achieving a perfectly hermetical seal, then this isn’t a huge problem.
Can Windows Protect Me from Poor-Quality Outdoor Air?
Keeping your windows shut can help limit how much smog, pollen, or other outdoor pollutants make it into your home, but it won’t stop them completely. There will almost always be some rate of transfer between your home and the outdoors, so even the best windows won’t block 100% of all pollutants… But they will significantly reduce your exposure when closed.
The best practice for maximizing indoor air quality is to check the prevailing conditions in your area, then deciding whether to open or close your windows. You can usually get a simple air quality rating from the weather app on your phone or online via sites like AccuWeather.
If air quality is good, you can open up your windows and let in some fresh breezes to air out your home. If air quality is poor outside, you can keep your windows shut until conditions improve.
What Other Indoor Air Quality Precautions Should Homeowners Take?
Windows are far from the only thing to consider when it comes to indoor air quality.
For example, the Florida Department of Environmental Protection strongly recommends taking precautionary measures like:
- Proactively maintaining your HVAC system to prevent mold/mildew growth.
- Setting up dehumidifiers in rooms with excess moisture.
- Checking the venting for any exhaust fans to ensure they vent outside rather than inside.
- Avoid paints, finishes, and cleaning supplies with volatile organic compounds (VOCs).
- Properly storing and disposing of any chemical compounds away from occupied rooms or rooms connected to your home’s air ducts.
- Not smoking indoors (tobacco smoke can be carried into air ducts and redistributed throughout the home, leading to health issues for other occupants).
These are just a few of the precautions that homeowners can take to improve indoor air quality so they and their families can lead healthier lives.
Get Windows That Seal Tight to Preserve Indoor Air Quality!
Need help finding the best windows to improve indoor air quality for your home? Reach out to Karoly Windows & Doors today to get a free in-home consultation.
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