Homes Are Airtight yet Dynamic
With a focus on energy efficiency and comfort, today’s homes are becoming more and more airtight. The trade-off for energy savings and efficient insulation is that these homes now trap contaminants and chemicals inside the building. For this reason, IAQ (indoor air quality) requires attention.
Most people believe that homes and their interior conditions are static, but that is the opposite of the truth. The interior of a home is dynamic, with ever-changing conditions based on the residents and the outdoor climate. Acts like cooking, showering, heat adjustments, number of guests, warm spells, cold spells, and more affect the conditions in the home..
Pro Tip: Richard Trethewey, This Old House’s expert on indoor air quality, puts it in vivid terms: “When the building was nothing but plaster, you could boil spaghetti all day long, you could take a shower all day long. But the modern home—the home built from 1975 on—is a tight thermos bottle. Whatever humidity we create can’t escape. That’s why the mold problems tend to come.”
Why Dynamic Home Interiors Require Monitoring
Since the interior of the home is prone to change, it requires monitoring to ensure that the air quality is healthy and safe. Indoor air quality tests check for proxies like temperature, humidity, CO2, Radon, particulate matter, pressure, and volatile organic compounds. Monitoring helps detail the conditions inside the home.
These readings are important because they can change dramatically over time. For example, a home might pass a Radon test when new or uninhabited, but with dynamic changes due to occupancy or changing conditions, Radon can reach unsafe levels. Monitoring can catch this.
Pro Tip: Ross Trethewey, This Old House home technology expert, emphasizes the importance of monitoring: “Knowledge is power. A monitor will let you know if your air quality is not that great, so you can do something about it.”
How to Monitor IAQ Levels Yourself
There are devices that homeowners can purchase to monitor the IAQ levels. These devices are about the size of a standard thermostat and can measure all of the necessary indicators. This data then translates to a computer or tablet for easy tracking over time.
While these devices don’t help the homeowner pinpoint the causes of the issue, they can indicate when the homeowner should call an expert for testing.
While most IAQ monitors use carbon dioxide (CO2) as a general indicator of air quality, few track carbon monoxide (CO) or radon. According to This Old House Magazine, carbon monoxide is the leading cause of accidental poisoning deaths in the U.S., and all homes should have a CO detector installed on each level. Radon, a carcinogenic gas, can be detected with an at-home test kit; if levels are high, a dedicated mitigation system that vents the gas outside should be installed.
Pro Tip: To understand how dramatically things have changed, consider the numbers: Ross Trethewey noted on This Old House that older homes breathed at a rate of 10 to 12 air changes per hour—meaning all the air in the house was completely replaced every five to six minutes. Today, new construction in Massachusetts is down to just three air changes per hour, thanks to spray foam and modern air barriers. That’s a massive reduction in natural ventilation, and it’s exactly why monitoring indoor air quality has become so important.
Resources
With an air quality monitor, Ross demonstrates how a few simple changes can change the air
quality in a home. If interested in testing your home’s air quality, Ross suggests selecting a
monitor with multiple sensors. Some of the most common proxies tracked for indoor air quality
include carbon monoxide, carbon dioxide, Total VOCs (volatile organic compounds), particulate
matter, temperature, humidity, and radon.
Pro Tip: As custom-home builder Jerry Effren explained in This Old House Magazine: “The goal was always to build homes that would stay comfortable, while expending less energy and costing less to keep them that way. You’d achieve that with things like adding insulation inside the walls, replacing drafty windows—pretty much anything to keep the warm air in and the cold air out. But all of that insulating meant that little to no air was escaping, and no fresh air was getting in.”
