As winter sets in and we prepare our homes, one question seems top of mind: how do you test for indoor air quality? And do you even need to? With extra time inside this season and more than the usual home upgrades, it’s not unusual to be concerned with the air we breathe inside our homes. We already learned that plants do no help with indoor air quality, but we wanted more help.

So, we brought in an expert to talk about air quality solutions.

indoor air quality testing monitor

There are many reasons Kelson Redding is an expert—he’s worked in HVAC and refrigeration for 6 years, he’s a Professional Engineer in HVAC and refrigeration, and he works on both residential and commercial spaces. But, like anyone who is concerned about indoor air quality, he lives in a home.


What is indoor air quality?

Kelson: Indoor air quality is a self explanatory term – how healthy the air in your home or business is to breathe, considering C02, carbon monoxide, mold, pollen, dander, etc. Sometimes temperature and humidity are considered as well, but those are more primary in terms of space conditioning, everyone is conditioning their air, but few are monitoring indoor air quality. 

A dramatically low percentage of people are monitoring things like particulate levels, C02, and carbon monoxide levels in their house. They have smoke detectors, and sometimes C02 detectors, which are great for emergencies, but not for understanding air quality.


Why is indoor air quality important?

Kelson: Last year I wouldn’t have put a great deal of importance on it. With this year’s events, in a normal home, you can have some issues without realizing it and it can impact your health. It is important, especially if you are making improvements to your home – whether it be windows, or HVAC related – to consider your IAQ and make improvements if you can. There are some non-invasive and relatively inexpensive ways to do that.


How do you test indoor air quality?

Kelson: There are homeowner/residential indoor air quality monitors that you can get for between $50 – $300 that tell you how much C02, carbon monoxide, and particulate you have in your space. That’s a great place to start. Some higher-end options include an app and actually drive action through your HVAC so the monitoring can be integrated with the ventilation system (if you have a ventilation system). Some will also provide data on specific particulates, such as mold and pollen.

You don’t always have to buy a kit to test your home. We have a slang term for utilizing your senses: the sniff test. Particulate issues you will be able to see or smell and it will be causing you irritation. It’s less hidden, whereas C02 and carbon monoxide are colorless, odorless, tasteless, and the effects are less acute. There’s no sneezing or itchy eyes, but you will be groggy and have low energy. It’s a silent killer.

So, why choose a high-end indoor air quality test? It’s a factor of budget and what issues you are concerned about. And also if you just like interesting data and toys.


Can you explain air sealing & ventilation systems and how they work together?

Kelson: Most homes are leaky enough that mechanical outside air ventilation is not needed in order to maintain good indoor air quality because you are getting it every time you open a door or window. There’s enough air exchange in a regular home to make up for C02 buildup from breathing. If you have a C02 monitor, that would alert you of a buildup.

If you installed Indow window inserts and are interested to know if you stopped enough air flow to where you would run into elevated C02, you could take a reading. As long as it’s not over 900 parts per million (PPM), then you don’t need to worry about new fresh air. If it’s over 900 ppm, then supplement by adding outside air ventilation, or cracking a window if the problem is minor and sporadic. In order to maximize energy efficiency however; there are options available for heat recovery ventilation so that you preheat or precool the fresh outside air with the already conditioned air being exhausted from the home. These units come in various sizes and configurations, and of course various cost levels as well.

window insert installed around ac unit as an air quality solution

How do air purifiers work?

Kelson: The HEPA air purification system is just a filter that catches contaminants pulled through a fan. Ionic air purification systems release negatively charged particles which bond to air pollutants that make them heavy and cluster. That causes them to fall out of the air onto whatever surfaces you have in the home, and eventually they are cleaned up with normal cleaning. Ionization systems are better for odor, smoke, and fumes, but they have limited coverage. HEPA filters are better if your main concern is particulate matter, but they have a higher energy penalty because the air is running through a filter or fan. If you can add a HEPA filter to your furnace, it would be very good at cleaning particulates in your home. Some furnaces can take a HEPA filter, but not all, so check before you get one.

how the layers of air filters work as air quality solutions

What if I got an Indow insert in every window, should I be concerned about IAQ?

Kelson: One factor is, consider the amount of people. A typical family of 4 in a 1500 sq ft house is just not typically enough breathing to elevate c02 levels. Based on my experiences, it’s worth the money to check, elevated CO2 could be messing with your energy levels and cognitive function and you wouldn’t even know it. So, you can buy the cheapest C02 monitor you can find, check each room, and that would be enough to see if you are ok. In general, it’s not a giant concern for homes. 

man installing window inserts as air quality solutions

Indoor Air Quality Solutions Depend on Your Situation

In general, if you’re concerned about your home’s indoor air quality, it’s a good idea to invest in a C02 monitor just to check. If you have a smoker in the house, a lot of pets, or have severe allergies, start to invest in a larger investigation. Kelson says, “If you are making significant changes to your building envelope, like Indow inserts or weatherization, get a monitor and then see what you want to do”.

There’s one more thing that Kelson recommends: change your furnace filter on a regular basis. He says it’s maybe the most overlooked thing in indoor air quality solutions. So, if someone in your household is having allergies, start there.

If you want to learn more about energy use in built environments, head over to They are a great team with fantastic resources.

woman replacing air filter as air quality solutions
Download Winterize Your Home Checklist

Get started on making sure your home is ready for the season and has good indoor air quality. Download our winter house maintenance checklist to stay on top of everything your home needs through this season.