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How to make sure the air in your home is healthy and clean

It’s more important than ever to breathe fresh, clear air. Here’s what you need to know.

It’s more important than ever to breathe fresh, clear air. Here’s what you need to know.

Key takeaways

  • COVID-19 has made us all more aware of the air we’re breathing. And there’s a growing body of research suggesting that, in general, poor indoor air quality contributes to a number of major health issues.
  • Why this matters: On average, Americans spend 90% of their lives indoors—and this was before the pandemic. So this is an issue that impacts almost all of us, now more than ever.
  • What you can do: Improving your home’s air filtration and circulation can make life indoors happier and healthier for you and your family.

Common sense tells us that fresh air is good for the body and mind. In the olden days, city-dwellers retreated to the countryside to experience the restorative effects of fresh country air. Even today, when we’re having a hard time focusing or perhaps feeling frustrated, many of us know to step outside for a “breath of fresh air.”

Since the 1960’s, American policymakers have invested a great deal of time and effort to ensure that the air outside remains fresh and clear. But what about the air inside? Americans spend 90% of their lives indoors, but we know far less about the quality of air we breathe in our homes and workplaces.

That’s beginning to change. COVID-19 is making everyone more aware of the air we breathe. And recent studies have shown that the air indoors can play a big role in our health. In one instance, reported by the consulting firm McKinsey, a group of diners in a restaurant contracted COVID when the restaurant’s air conditioning system blew air from an asymptomatic patient to other tables.

Researchers now know that the air quality inside your home can be up to 10X worse than the air outside.

Of course, we don’t spend all of our time in restaurants. So it’s also important to understand the air where many of us are spending most of our time: at home. Until recently, there was very little information on the subject. Researchers at the University of Colorado, however, have for the last several years been leading the first-ever comprehensive study of in-home air quality. Using a research home loaded with sensors and gadgets, the researchers have begun to study the impact of common household activities like cooking and cleaning.

The findings so far have been jarring. Researchers now know that the air quality inside your home can be up to 10X worse than the air outside. While there is still a lot we need to learn about indoor air quality, we do know this much: since we all spend so much time inside, it doesn’t hurt to think about how we can improve the air we breathe.

In this article, we’ll take a closer look at the science of indoor air quality, and show you how you can clear the air at home—without breaking the bank.

What does it mean when we say “poor air quality”?

Typically, air quality is measured by what’s known as a “particulate count”. This is a tally of the very small particles (likely invisible to the eye) floating alongside the air molecules you breathe. The higher the particulate count, the more debris in the air, and the less healthy the air is for you to breathe.

A common measure of outdoor air quality is the Air Quality Index (AQI). You can find AQI readouts in many of the weather apps on your smartphone. The latest research shows that during certain household activities, like cooking a big meal, raises the AQI in your kitchen to the same levels found in the world’s most polluted cities on their smoggiest days.


An induction stove is healthier for your indoor air than a gas stove: a gas stove can produce elevated levels of Nitrogen Dioxide, a toxic gas, which can have particularly harsh impact on children’s health.

What’s the long-term health impact of poor indoor air quality?

Because research on indoor air quality is still in its early stages, scientists have yet to draw many definitive conclusions about its long-term effects.

The good news is that the human respiratory system is extremely resilient. The likelihood of damage from short-term exposure to unhealthy air is very low.

However, prolonged exposure to air with high particulate count has been proven to lead to respiratory issues like sinus infections and asthma attacks. These initial respiratory illnesses can also make us more susceptible to further health issues down the line. The UK estimates that poor indoor air quality is attributable for at least 9,000 deaths a year. And the World Health Organization estimates that 5% of lung cancer deaths can be attributed to airborne particulates.

By taking a few smart steps, the negative impact of these activities can often be mitigated altogether.

What causes poor indoor air quality?

First, the bad news:

Many daily activities can have a short-term negative impact on your home’s air quality:

  • Cooking: As mentioned above, cooking can dramatically alter the air quality in your kitchen. In one recent experiment, researchers at the University of Colorado tracked the air quality in a kitchen while cooking a traditional Thanksgiving meal. They determined that the indoor air quality had deteriorated significantly enough to qualify as an “airborne toxic event.”
  • Household cleaners and even personal beauty products: Many everyday products—for instance, hair spray, or the products you use to wipe down surfaces in your kitchen and bathroom—emit fumes that radically alter the quality of air in your home. In one study, mopping with bleach after cooking with a gas burner triggered a chemical reaction that produced nitryl chloride, a chemical known to create coastal smog.
  • Heating and cooling your home is another big culprit. Fuel oil-fired heating appliances give off health related air pollutants like sulfur at about 130x that of natural gas heaters [Brookhaven National Laboratory, US Department of Energy], and can also become a source of carbon monoxide emissions. Fireplaces and woodburning stoves put even more particulates into the air. Burning wood inside the home is also a known cause of problems for people with allergies.

Now, the good news:

Many of these effects are only temporary. And by taking a few smart steps, the negative impact of these activities can often be mitigated altogether.

How do you know if you have poor indoor air quality?

If you want to assess your home’s air quality, you have a few different options:

Test your air quality: First, you can go the high-tech route. An article from Wired last year reviews one of a growing number of home air quality test units. These machines can be pricey, and while they may be good at identifying unhealthy air, they’re not great at showing you how to clean it up.

Use your eyes: Luckily, you don’t need an expensive monitor to see unhealthy airflow. You can identify many problems with the naked eye. Mold buildup inside the house can indicate that the airflow is off; it’s also a frequent contributor to health issues. Steamy windows, uneven temperature zones, and even excessive buildups of ice on your roof can also be signs that the airflow in your house is off.

What are the easy fixes for poor indoor air quality?

If you’re noticing unhealthy air, or the symptoms of poor airflow in your house, there are a few easy ways of addressing the problem.

  1. Open the windows: It may sound like a no-brainer, but opening the windows will often make an immediate difference. For instance, if you’re cooking a big meal, getting the windows open is a great way to help keep the air in the kitchen healthy. There is one big caveat here: to get healthy air inside, the air outside must be healthy. So if you live near a busy road, or if it’s a smoggy day outside, you may want to consider other options.
  2. Improve your kitchen ventilation: A hood fan can get funky air out of the house in a hurry, or filter it before returning it to the kitchen. And switching from a gas range to an induction stovetop has also been shown to make a big difference.
  3. Say so long to your fireplace: That roaring fire may look nice, but bringing wood into the house and burning it for fire can really impact people with allergies and asthma.
  4. In-room air purifiers: In-room air purifiers are useful, but they often cover only a single room, so you would need to get units for all rooms where you spend significant time to realize the full benefit. Individually they can be expensive, and the cost of operation (electricity and filter replacements) can add up in a hurry.
  5. Sound the alarm: A carbon monoxide alarm is an essential, affordable tool for preventing dangerous air inside the home.

Do plants improve indoor air quality?

Everyone knows that plants are one of nature’s best air purifiers. But the truth is you’ll need a lot of them to improve the air quality indoors. To be specific, you’d need about 80 plants per room, according to Wired. So buy as many ferns and ficuses as you like. But just know they won’t do much to filter your great indoors.

Making a bigger difference

If you want a big, lasting difference in your home, you’ll need to improve two things: your home’s ability to control airflow, and its ability to clean the air. This is exactly the work Sealed has performed for hundreds of homeowners over the years. Here’s how we do it:

Regulating airflow

Air sealing and insulation form a 1-2 punch that helps regulate airflow inside the home. Insulation regulates temperature, which keeps the heat inside in the winter, and outside in the summer. And air sealing prevents unwanted air from getting into the house—most homes have 3-4 times more airflow than is necessary.

Proper air sealing and insulation is critical to keeping particulates outside of the air your breathe inside your home.

It’s important to note that both air sealing and insulation work should only be done by qualified professionals. Getting the airflow right in your house is a delicate balance. Too much air sealing might lead to the problem of “overtightening,” which can contribute to stuffiness. And too much insulation can actually be counterproductive, and limit your home’s ability to regulate temperature.

To learn more about how Sealed gets this important work right, read our guides to air sealing and insulation.

Insulation regulates temperature, which keeps the heat inside in the winter, and outside in the summer.

Whole-home air filtering

In its report, “Can HVAC systems help prevent transmission of COVID-19,” the consulting firm McKinsey highlights different methods for cleaning the air throughout indoor spaces. Of the four methods reported—irradiation, thermal, filtration, and air ionization—filtration was shown to be most effective. Not only is it the cheapest to implement, it also works best by placing a physical barrier between particulate matter and the air you breathe. (This is also why masks have been an effective tool in limiting the spread of COVID in public spaces.)

There are a number of ways to apply whole home air filtration. At Sealed, we recommend a whole-home heating and cooling system run with heat pump technology.

Heat pumps are a marvel of modern HVAC. They heat and cool your whole home—but they’re up to 3X more efficient than traditional heating and cooling systems. They constantly recirculate the air inside to keep it fresh. And they have built-in filters that filter everything that comes into your home.

Improving your home’s air quality can get expensive, but we don’t think you should have to put a price on your family’s health. That’s why we cover the upfront costs of the work: you only pay us back if you save energy afterwards (learn more about payments with Sealed).

For more information, read the Sealed guide to heat pumps, or check out our Climate Control plan.

September 8, 2020