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“The connection between health and dwelling is one of the most important that exists.” - Florence Nightingale

The discussion about indoor air quality (IAQ) and healthy homes has been around for decades. But in the past few years, homeowner interest has grown significantly. People spend approximately 90 percent of their time indoors. According to the Shelton Group’s pre-pandemic polling, 72 percent of Americans understood their homes have an impact on their health, and 60 percent were concerned about indoor air quality. In other words, it’s likely that most of your customers were already seeking advice about how to improve their home’s indoor air quality, even before COVID-19 and wildfires became headline news.

Increased awareness of how a home’s air quality impacts health cuts both ways. On the one hand, that awareness can empower a qualified contractor to offer the right solutions to customers. For example, they can explain how high quality HVAC equipment and proper air sealing saves money, increases comfort, andenhances IAQ. On the other hand, that increased attention can result in a lot of noise and distrust. Your customers may have heard about a lot different solutions online, from neighbors, or from other contractors. Many people come to believe a single technology can be a silver bullet. So when you offer your solution, you have to be careful not to be perceived as selling snake oil.

When discussing indoor air quality with homeowners, Pearl emphasizes four key elements:

  1. Prevention / Source Control - Stop pollutants from entering the home.
  2. Ventilation - Bring in fresh air to dilute pollutants, and remove stale air.
  3. Filtration - Filter your home’s air to complement your home’s ventilation system.
  4. Controls and Monitoring - Monitor, measure, and take action, as needed.

Let’s look into these in more detail.

1. Prevention / Source control

Keeping pollutants from entering the home will often be outside of contractors’ control. Recommending that your customer should quit smoking, improve their cleaning practices, or get rid of the family dog is probably not a winning strategy (although recognizing that these sources exist is important for your recommendations). But the following sources of pollutants are things contractors can help homeowners address:

  • Air leakage. Holes in a home’s shell exist in the attic, walls, windows, or foundation. Air sealing can reduce radon and other soil gases, outdoor pollutants including wildfire smoke, pests, and humidity (a common, serious and often underestimated problem).
  • Atmospherically drafted combustion appliances. Furnaces, boilers, and water heaters can spill carbon monoxide and other combustion pollutants into the home.
  • Leakage in ductwork. Improperly sealed return ductwork can draw contaminant-filled air from crawl spaces, attics, and other unconditioned spaces.
  • Improperly balanced forced-air systems. Over-pressurized rooms can lead to condensation that results in mold and mildew within the wall cavities. Under-pressurized rooms can do the same — as well as draw in contaminant-filled air from crawl spaces, attics, and other unconditioned spaces.
  • Bacterial growth on the indoor coil. Fungi and other bacteria can flourish in wet, cold places. UV lights can mitigate that contaminate source — as long as they do not generate ozone, which just adds another pollutant to the home.

2. Ventilation

Breathing, cooking, taking showers, opening doors, and simply using homes introduces contaminants into the indoor air. There is no perfect source control, but consistent with ASHRAE 62.2, Pearl encourages:

  • Spot (local) ventilation in rooms where activities introduce contaminants. Full bathrooms and kitchens need to have properly exhausted fans to remove excessive humidity. Cooking also introduces small particles, known carcinogens, smoke and odors. If the kitchen has a gas oven or range, byproducts of combustion gas are also introduced. Workshops and even garages also benefit from depressurization.
  • Whole-home ventilation. Delivering fresh air and removing stale air with a balanced ventilation system throughout the entire home is your best option. Even carbon dioxide is a pollution at high levels that causes fatigue and headaches. Whole-home ventilation mitigates the presence of virtually all pollutants (assuming the system is properly designed, installed and maintained). While not as ideal as a balanced system, supply-only or exhaust-only whole-home ventilation strategies are effective and less costly solutions to deliver whole-home ventilation.

3. Filtration

Filtration also plays an important role in protecting a home’s air quality. MERV-rated filters and electronic air cleaners filter out particles and, in some cases, even viruses. For example, MERV 13+ filters have appeared to be effective in filtering the coronavirus. As with all IAQ solutions, proper design, installation, and maintenance is crucial. Proper airflow must be maintained, and a professional should measure static pressure drops to ensure the HVAC system’s health isn’t compromised due to a mismatch with the filter type.

4. Monitoring and Control

A home is a very dynamic environment. External factors like temperature, humidity, direct exposure to solar, and the composition of soil gases and ambient air pollutants (pollen, smoke, etc.) can introduce pollutants into the home. Occupants use the home in a variety of ways that can also add contaminants. And a home’s materials and mechanical systems can either help or hurt indoor air quality.

So what’s a homeowner to do? 

Well, knowledge is power. The ability to measure and control humidity might be the most important IAQ factor to know and address. Humidity is a little like Goldilocks — too little is bad and too much is bad. You have to get it just right. The Sterling Chart is a tool that demonstrates the importance of keeping to the middle of the relative humidity spectrum.

But humidity is far from the only indoor air concern that can be monitored and controlled. With smart home technologies, homeowners can better understand the air quality in their home and take appropriate actions. Indoor air quality monitors can be placed in kitchens and alert homeowners to turn on the exhaust fan.

How Does Pearl Incorporate IAQ?

Broadly speaking, Pearl incorporates indoor air quality into its certification system in three areas:

  • Pearl Certification Points. Pearl points are awarded for a variety of features that contribute to source control, ventilation, filtration, or monitoring and controls.
  • Pearl Certification Levels. Understanding how well a home’s shell controls movement of air through the building is critical. Performing a blower door test is a requirement for any home to reach Pearl Certified Gold and Platinum levels. The test results should be used whether the homeowner is considering envelope upgrades or a new HVAC system. For Platinum, a home must have a whole-home ventilation system (balanced or not) and the HVAC system must be properly designed and installed. This requirement is less about energy, and more about recognizing how important a home’s mechanical systems are to indoor air quality.
  • Education, awareness, and recommendations. Pearl is a trusted third-party source of information on high-performing homes. And our new Green Door app is a great tool for homeowners to learn all about their home’s performance. The discussion of indoor air quality is complicated. The home is a dynamic system of systems. Pearl helps homeowners understand indoor air quality, and rewards them when they make investments in improving their home’s IAQ. While each home is different when it comes to IAQ needs, here are some general recommendations that apply across the board:
    • A well-qualified contractor is the best source for addressing IAQ problems in your home. Pearl’s recommendations represent best practices and are broadly applicable to many homes. But a well-qualified professional’s recommendations are the most appropriate source for specific solutions based on the specific issues and needs of a particular home and homeowner..
    • Choose 2-stage, multi-stage and variable capacity heating and cooling systems. Focus less on SEER and AFUE, and more on the ability of the appliance to perform well in a dynamic environment. The ability of a home’s heating and cooling system to regulate based on changing demand is as important for IAQ as it is for comfort and energy savings.
      • The flip side of this recommendation is to generally avoid single stage equipment. However, if single stage equipment is selected, Pearl strongly recommends that blower door test results are factored into a full load calculation for the home. Improperly sized and selected single stage equipment can result in a variety of comfort, indoor air, and energy problems and shorten its lifespan. Single stage systems can be an affordable and appropriate solution when properly installed.
    • Knowledge is power. Test, measure, and maintain. Point-in-time testing of a home’s air leakage and HVAC system are important pieces of the IAQ puzzle. Enhance point-in-time testing with real-time monitoring of the air and the systems in the home that impact the indoor environment.

Do you have more recommendations that Pearl should consider? Or do you take issue with any of the items mentioned above? Please contact us to discuss — we value your feedback!

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