In today’s fast-paced world, our home environment significantly impacts our health and wellness. Amid concerns about indoor air quality (IAQ) and the rise of health-related issues, it’s essential to understand the significance of ventilation. We talked to an experienced Aranet4 HOME user and seasoned architect Melvin Lau, who shared valuable insights into the world of IAQ.

Melvin Lau is a practicing architect (AIBC) and a Certified Passive House Designer (CPHD) from Vancouver, BC, Canada. He has a master’s degree in architecture from the University of Manitoba (2013) with experience in mixed-use, residential, high-performance, and passive house projects as well as improving indoor air quality and reducing carbon emissions through design at the moment working for Ryder Architecture.

The Significance of Indoor Air Quality

As someone designing buildings, Melvin has been interested in IAQ for quite a while. Since forest fires in British Columbia have spiked in the last couple of years and the pandemic has added stress about the air quality in relation to health and wellness, that focus has only increased.

Places with high concentrations of CO2 may be a concern for underventilation. As a passive house designer, I know that overventilation can also be an issue with dry air. So I’ve been looking at various metrics: temperature, humidity, CO2, VOCs, and particulate matter (PM),” Melvin elaborates.

Experience With Aranet4 Indoor Air Quality Monitor

Melvin has been using an Aranet4 for about two years to conveniently and portably monitor the air quality around him. “It’s an interesting way of bringing an air quality monitor around and seeing what the air quality levels are because it doesn’t have to be plugged in and has an interface where you can see the CO2 right away,” he comments.

So far, Melvin has used it mainly in transit, especially on buses, and in work environments. “The worst I’ve seen was over 4 000 parts per million on a full bus, even with ventilation on,” he shares.

Photos taken by Melvin Lau

According to his observations, the situation can be better on Vancouver’s SkyTrain, where the CO2 levels average around 1 200 ppm. Standing my the sliding doors opening at regular intervals and the doors being leaky in nature while traveling at higher speeds, in Melvin’s opinion, make a big difference.

Choosing the Right Ventilation System

Ventilation and heating energy is a balance we need to play with,” Melvin stresses. He adds that the problem with modern houses is sometimes prioritizing energy over air quality by simplified energy standards. This might indeed save energy but at the cost of indoor air quality and the occupants’ health and wellness.

So if you’re just hitting the heat demand target and not dealing with ventilation, then that’s the recipe for spoiling the air quality because you have a very airtight building, but you don’t have any fresh air or you’re strictly trying to deal with it through windows or doors,” Melvin explains, adding that a lot of spaces don’t even have cross ventilation options to solve this manually.

In Melvin’s opinion, it’s very important to use a standard that looks at a building holistically when planning, building, or redesigning a space, such as the Passive House standard. That means taking not only energy but also building durability and healthy indoor air quality into account.

Understanding the Passive House Standard

To solve the various challenges a modern living space presents, Melvin specializes in passive house design. This innovative approach revolves around five core principles: insulation, minimizing thermal bridges (like at windows and balconies), airtightness, high-quality windows, and heat recovery ventilation. Melvin emphasizes the critical role of a heat recovery ventilator (HRV) in ensuring energy efficiency and indoor air quality.

In simple terms, the HRV features four outlets that bring in fresh, outdoor, filtered air while efficiently recovering heat from stale indoor air, maintaining a comfortable atmosphere without cross-contamination. This clever, low-maintenance system operates by exchanging heat between indoor and outdoor air, with efficiency rates generally ranging from 50 to 90 %. Forget relying on open windows; HRV systems offer optimal energy efficiency, fresh, filtered, controlled ventilation for your home.

Having a very airtight building is very good. A continuous insulation layer around the building and no thermal bridges means no condensation. And without condensation, you don’t have mold growth. So that takes care of the VOC issue. The HRV then deals with the particle matter and the CO2. So the combination of insulation, airtightness, ventilation and filtration, that is an excellent combination for healthier living,” Melvin summarizes.

Detecting Signs of Poor Air Quality: Expert Tips

When looking for a new living space or evaluating the one you already occupy, there are things we can do to understand and improve how healthy the space is.

In our expert’s opinion, it is important to pick one with airtight construction, tested for unit and building airtightness, and a balanced, mechanical ventilation system. “That would ensure a continuous flow of fresh air, essential for avoiding CO2 buildup. If it isn’t available, consider a low-speed continuous exhaust fan. Even a bathroom fan running at a lower speed could help to deal with the CO2 buildup.

When it comes to warning signs, Melvin stresses discoloration, “It often hints at lurking issues within a building.” If the paint should be white but is yellow or black, especially in odd corners, that could indicate a weak spot in the building with condensation and potential mold growth.

Single-pane, old, metal windows would likely be a source of condensation and mold growth too. Remember that fitting new windows is not always a foolproof solution since the insulation of the walls is important as well. “It might be good to install the window first, but then you’ll need to plan for the future stages so that the window can integrate with other upgrades.

The architect also suggests considering planning and retrofitting to EnerPHit, a standard developed by the Passive House Institute. “Upgrading buildings involves applying principles similar to new constructions adapted to the specific climate and needs. It’s not just about sealing the building. You don’t want an airtight space without proper ventilation, as it leads to stale air buildup over time,” Melvin explains, adding that retrofitting is best done in collaboration with a specialist.

The Aranet team thanks Melvin Lau for offering insights and guidance for healthier indoor spaces. We hope this will help you balance mindful choices and well-ventilated spaces, nurturing not just our homes but our well-being.

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