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Building to Code Doesn’t Guarantee a Healthy Home

Poor air quality in your home can impact your health

By Bill Hayward

Have you ever wondered if your home is impacting your health?  Surprisingly, over 60% of Americans ask themselves this question. After my whole family got sick in a newly remodeled home, I set out to make the answer to that question accessible to all for free.  

The Hayward Score team combined the best available building science, medical science and field experience into a set of complex algorithms to calculate a home score. The lower the score, the more likely your home is impacting your health. We then recommend house interventions along with habit changes to make a home or rental healthier. 50% of Hayward Score users report feeling better after making the recommended changes. So far, we’ve scored 88,000 dwellings resulting in 44,000 households feeling better! It’s a start.

To calculate a score ( we ask approximately 50 questions about your home, proximity to outdoor pollutants and habits like running bath fans and chemical storage. We use your zip code to make the calculations and recommendations appropriate to your climate. People self-report on 23 different medical symptoms commonly associated with unhealthy homes. This is now the largest database correlating health, homes and occupant habits in existence.

The lower the Hayward Score the more symptoms people report and the more often they report their symptoms go away when they leave the house only to experience them again when they return. Conversely, in high scoring homes with properly installed energy recovery ventilation (ERV) people report very few symptoms along with very little internal dust and unpleasant odors and smells. The Hayward Score database now provides us a data driven definition of a healthy home by climate. It also demonstrates through our follow-up studies that symptoms disappear when people improve their homes and habits.

Designing a new home or remodel? Take 10 minutes to run it through the Hayward Score. Follow the design recommendation provided to upgrade the new project to be healthier.  Amazingly, building to code doesn’t guarantee a healthy home. Codes are written by committees and tend to be 10 years behind our national best practices. Green builders know this because they are often exceeding code to achieve sustainability goals.  

I often ask audiences this question. “When all the doors and windows are closed, where does the air you breathe come from?”  After some moments the answer “seeps” in.  Air leaks in through the cracks, crawl space, attic and walls carrying with it dust, dirt, mold spores and outdoor pollutants that concentrate indoors leading to unhealthy homes. The first step is to stop the air leakage and fill the house full of filtered, fresh air using an ERV. Specifically, build to an airtightness of 1-2 ACH @ 50pascal (code is 3-5 ACH based on climate zone) and use an ERV to provide approximately one air change every 2 hours and at least 20 CFM per person occupying a bedroom.

Green builders are accustomed to systems thinking. When you build to an airtightness of 1-2 ACH, upgrade your windows to a thermally broken, high performance U-Factor and add a high efficiency ERV magic happens. You can reliably predict the home’s thermal performance which means downsizing the HVAC system and reducing the ducting requirements in the range of 50%. The savings makes this move to health affordable. Equally importantly, you can now market the benefits of your healthy home in our rapidly growing wellness real estate market while reducing callback risk.

Covid propelled us into the “Age of Air” where people care about the air they share. Homes that augment our health instead of degrading our health are what the market wants. Healthy homes are peacefully quiet, pest free and have very little dust thanks to the airtightness and filtered ventilation. These values capture consumer attention and compete favorably with granite counters, fancy appliances and walk-in closets. You will find health a more powerful driver to motivate buyers to build healthy, durable and energy efficient.

Although I spent the last 30 years running lumber yards in the construction business, my 7-year 

journey to invent the Hayward Score and my immersion with the national researchers on healthy homes has taught me we are all now in the healthcare business. “Our homes have more to do with our long-term health and wellness than our doctor.”  

Bill Hayward is the CEO of Hayward Lumber and Founder of He can be reached at