Improving Indoor Air Quality in Energy-Efficient Home

In May 2023, a Respira biofilter living wall was installed in a residential home in Ontario, Canada. The homeowner recognized the importance of maintaining high standards of indoor air quality (IAQ), as it is a critical aspect of indoor environmental quality (IEQ), impacting the health, comfort, and well-being of occupants. This decision came with impeccable timing as 2023 became one of the worst years in Ontario for air quality ratings.

The homeowner’s decision to install the Respira biofilter living wall was driven by a desire to improve indoor air quality without relying on increased ventilation, which can lead to higher energy consumption. The living wall provides a natural and sustainable method of air purification for the home, using plants to filter out toxins and pollutants from the indoor air. By improving indoor air quality in a sustainable manner, the Respira living wall offers a solution that promotes a healthier home for occupants and the planet.

BACKGROUND

The home was built in 2015 by Chatsworth Fine Homes. The 14,000-square-foot residence is situated in East Oakville’s lakeside residential area near Toronto and combines advanced building science with thoughtful design. In 2017, the home earned the BILD Custom Home of the Year Award and is described as being super-engineered, socially responsible, and aesthetically pleasing.

Some of the home’s energy-saving features include home automation, triple-glazed windows, an insulated concrete shell, a rainwater cistern for landscape irrigation, and 20-kilowatt solar panels. “The owner prioritized energy efficiency and environmentally responsible materials,” notes Chris Sliskovic, president of Life Drywall Systems, Ltd., who possessed the framing, drywall and finishing contract during the construction phase of the build. The homeowner sought out the best of the best, recognizing the value in using superior products for their home. However, these new homes that are constructed with increasingly tighter building envelopes to improve energy efficiency inadvertently have an impact on indoor air quality. The enhanced seal, meant to keep heat in and reduce energy costs, also traps indoor air, leading to reduced circulation, stagnation, and – consequently – a decline in indoor air quality. This scenario necessitates modern solutions to ensure that while homes remain energy-efficient, they also maintain a healthy indoor environment through improved ventilation and air purification technologies.

In 2023, the homeowner faced the challenge of maintaining clean indoor air without sacrificing the energy efficiency of his home. Traditional methods of improving indoor air quality often rely on increased ventilation to dilute pollutants and improve air circulation. While effective, these methods are energy inefficient. Increased ventilation requires more energy to heat or cool the incoming air and increased treatment of the air to ensure it is filtered before it enters the indoor environment, all of which leads to inevitably higher energy consumption and costs.

AIR QUALITY:

A recent survey revealed a significant shift in public concern towards air quality, with 68% of Canadians now expressing concern over outdoor air quality, marking a notable increase from previous years. This growing awareness underscores the importance of addressing indoor air quality as well, as individuals become more conscious of the air they breathe both outside and inside their living and working spaces.

Outdoor air quality plays a crucial role in determining the quality of air indoors. Events such as wildfires, industrial pollution, and vehicular emissions can introduce pollutants into the outdoor air, which can infiltrate indoor spaces through ventilation systems, open windows, and other pathways. For example, the wildfires that swept across Ontario during the summer of 2023 led to a decline in outdoor air quality, greatly affecting indoor environments as well.

OBJECTIVES:

The homeowner’s objective was to find a solution that would effectively purify the air inside his home and provide humidity regulation without increasing ventilation and sacrificing the home’s energy efficiency.

CHALLENGES:

The installation was relatively seamless. The space was designed with the intention of having the biofilter installed, so there was easy access to a water hookup, drain and sloped floor, plugs on the ceiling for grow lights, and access to the back side of the wall for easier installation.

SOLUTION

The Respira biofilter living wall was proposed as a solution. The biofilter living wall is designed to act as a natural air purifier, using plants to filter out toxins and pollutants from the air.

Although many people believe that plants clean the air on their own, research conducted by Toronto Metropolitan University, the University of Guelph, and the National Research Council of Canada indicates that the root zone of plants can have a symbiotic population of beneficial microbes that break down and permanently destroy airborne pollutants. This process is known as biofiltration. The Respira biofilter has integrated fans that actively circulate the air past the plant’s roots, which are planted hydroponically (i.e. without soil). This air circulation method allows the beneficial microbial communities to remove toxins from the contaminated air.

An additional benefit of the Respira biofilter is that it offers humidity regulation; achieved through the onboard fans which were scheduled on interval timers.

By actively circulating the air in the indoor environment, the requirement for ventilation does not need to increase and can, in fact, decrease the number of air change cycles. As such, the Respira biofilter emerged as the perfect solution for this homeowner’s requirements.

IMPLEMENTATION

The installation of the Respira living wall began with careful planning and design. In this stage, we worked closely with the client to ensure the installation was aligned with their vision. The living wall was integrated with the existing ventilation system so it could effectively purify the air throughout the entire home. The installation of the 11ft by 9ft biofilter took around two days to complete.

The living wall is equipped with an automated irrigation system to provide the plants with the water they need to thrive. The automated irrigation system was designed to deliver water to the plants at regular intervals, ensuring they received the right amount of water without overwatering. Since the system is hydroponic, this watering cycle is vital as it is also how the plants receive their nutrients. Building the system in this way allows for more control over the growing environment, making certain that the plants receive the right amount of nutrients and water to support healthy growth.

Regular maintenance visits were scheduled to check the health of the plants and make any necessary adjustments to ensure optimal performance.

RESULTS

Since the installation of the Respira biofilter living wall, the homeowner has noticed a substantial improvement in their indoor air quality. With the biofilter system in full effect, the living wall has effectively removed toxins and pollutants from the air, creating a cleaner and healthier indoor environment. The data tracking the air quality of the home since the installation of the Respira biofilter shows a general demonstration of excellent air quality post-installation.

One of the most notable aspects of the living wall’s performance was its resilience during external events, such as the wildfires that swept across Ontario during the summer of 2023. Despite the plummeting outdoor air quality due to the wildfires, the data collected from the indoor residential environment remained unaffected, showcasing the effectiveness of the living wall in maintaining clean air indoors.

Another significant benefit the client experienced was the added humidity within the home. Regulated humidity levels are crucial for maintaining healthy indoor air quality. Maintaining humidity within a recommended range (typically 30-50%) can deter the proliferation of dust mites and other allergens. Additionally, regulated humidity levels can enhance occupant comfort by preventing air that is too dry, which can irritate the skin, eyes, and respiratory system. Notably, the Respira system was able to keep humidity at or over 35% throughout the dry winter months, even when the outdoor temperature dropped below -10°C.

The homeowner also mentioned that, with the addition of the Respira biofilter in their home, they were able to keep their humidifiers and their energy recovery ventilator (ERV) off all winter. A total of four steam humidifiers and four ERVs were completely shut down, saving significant power.

CONCLUSION

The installation of the Respira biofilter living wall in this Ontario home has proven to be a successful solution for improving indoor air quality in a sustainable manner. The living wall’s ability to effectively purify the indoor air, regulate humidity, and remain resilient during external events without relying on increased ventilation makes it an ideal choice for homeowners looking to maintain clean air indoors.

Overall, the Respira biofilter living wall has provided the homeowner with a cleaner and healthier indoor environment, showcasing its value as a sustainable and effective air purification system.