Understanding The Tension Between Indoor Air Quality And Energy Efficiency
Posted on: 22 August 2022
If you're an energy-conscious homeowner, you've probably come across the concept of a building envelope before. While this term can sound technical, it simply describes the imaginary barrier between your indoor air and the outside environment. Your home's envelope includes everything from insulation to windows and walls.
A more energy-efficient home will have a more tightly-sealed envelope. Since there's less ability for air and energy to travel across this barrier, your conditioned air will remain at a comfortable temperature for longer. Unfortunately, a tightly-sealed building envelope is often at odds with the concept of good indoor air quality.
The Relationship Between Efficiency and Indoor Air Quality
A key concept for indoor air quality is the air change rate, often expressed as air changes per hour or ACH. Your home's ACH is the number of times your HVAC system refreshes your home's air every hour. For example, an ACH of 6 indicates six changes per hour or one complete air change every ten minutes. A higher ACH generally provides better indoor air quality.
Older, poorly-sealed homes often have a higher air change rate than newer homes with better construction and insulation. Since these homes have a weaker envelope, the overall structure is "leakier." As a result, there's a greater exchange rate with the outside air. This situation is bad for efficiency but can lead to fresher indoor air.
While newer homes are more efficient, their tighter envelope can result in a lower overall air change rate. Instead of drawing in outside air, these homes primarily rely on the HVAC blower to circulate air and pass it through a filter. This improved design can have serious implications for your home's indoor air quality.
Evaluating Your Home's Air Quality
Improving the air quality in your home can be challenging, and it requires understanding factors such as your air change rate. You may need to rely on different methods to improve air quality in older homes than you would in newer, more tightly insulated structures. For example, newer homes may require a whole-house ventilation system to maintain an adequate air change rate.
An indoor air quality (IAQ) evaluation is the best way to collect this information so you can make an informed decision about future improvements. Many IAQ evaluations include ventilation tests, giving you a reasonable estimate of your home's air change rate. You can also learn about the specific pollutants and contaminants impacting your air quality.
If you're serious about getting fresher, cleaner air into your home, this information is crucial to making effective and budget-friendly choices. An air quality evaluation report, combined with a little knowledge about how the design of your home affects its air quality, will allow you to choose the best options to ensure your whole home can breathe a little easier. For more information on indoor air quality evaluation, contact a company near you.
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