Rethinking ventilation systems to create healthier homes
Every so often, one might feel the need to step outside or crack open a window to get some much-needed fresh air after spending an extended period of time indoors. After worldwide shelter-in-place orders confined many people to their homes, some may have felt this urge even more so. Prior to the COVID-19 pandemic, the majority of people spent 90 per cent of their time indoors. Although outdoor pollution is generally the first thing to come to mind when we think of air quality, according to experts, indoor air is more contaminated than what we encounter outdoors, which makes our need to step outside or open a window to breathe fresher air all the more understandable and harder to ignore.
We live in environments where pollutants in the home are two to five times higher than outdoor levels when our homes are unable to properly exchange old air with fresh air. According to the Environmental Protection Agency, a six-room home collects an average of 40 pounds of dust containing up to 45 toxic chemicals in a single year. With multi-residential or multi-use buildings (MURBs) there are even more air quality considerations with the need to factor in indoor common areas such as hallways, staircases, lobby’s and elevators, leading to compounding indoor pollutants.
Buildings that breathe
As buildings are made to be more energy efficient and “leak proof” they are also making the air we breathe everyday less healthy. Airtight buildings that keep heat and cool air inside may lower energy bills, but they also keep out fresh air. The key to a healthy home is ensuring there is proper ventilation, which functions much like a set of healthy lungs that keep the good stuff (cool and clean air) in, and move the bad stuff (heat, moisture and indoor air pollution) out. Without that air exchange, moisture can breed mould and mildew, allow dust mites to flourish and can even lead to a greater risk of health issues.
As explained by Canadian environmental doctor Dr. John Molot and author of 12,000 Canaries Can’t be Wrong (2013), “The air that we breathe is the largest source of pollutant assaults that our bodies have to deal with. What may come as a surprise is that indoor air is more contaminated than outdoor air and the tighter the building is, the more responsibility the ventilation has for ‘breathing for us’: it must bring in the oxygen and exhaust the carbon dioxide. If the ventilation is inadequate, the carbon dioxide levels indoors will increase.”
Even to those astute to indoor air quality, there are several factors that can reduce the quality of the air we breathe indoors. Certain building materials like wood and carpets as well as finishes in our homes can exude pollutants that are invisible to the naked eye and harmful to our health. Particulates from cleaning products, smoking and cooking can affect our health as well. In a less than ideal environment, VOCs, CO2, moulds, allergens and other pollutants can accumulate, creating the potential for serious health issues to manifest. Certain biological pollutants that are not properly filtered out of indoor air have been linked to the onset of asthma, headaches and concentration problems, which make it difficult to sleep, study and work.
The roles of ventilation systems
Presently, there is no recommended response for buildings to change building ventilation in response to the COVID-19 pandemic. However, as the role of aerosol transmission is hotly debated, it is important that building systems are functioning as intended to prevent potential ventilation problems that could worsen airborne transmission.
To better understand how we can create healthier homes to protect ourselves for current times and the future, we first need to understand the three types of ventilation systems that can be used separately or together. Each system has its own unique benefits towards the goal of obtaining healthy indoor air quality that are important to recognize and use.
Natural ventilation, as the name implies, is the natural movement of air currents and flows through a home independent from technology. Natural ventilation is located wherever openings in the building envelope are located. Wind ventilation is commonly used in homes and is nothing more than opening windows and doors to allow unfiltered outside air to circulate throughout the rooms. Every time we open a window or a door to get some fresh air, we are practicing natural ventilation. It can also take place through a process called infiltration, where fresh air sneaks in through leaks and cracks in the home itself.
A spot ventilation system uses technology to provide ventilation to very specific spots throughout the home. Most often, these forms of ventilation are located in basements, attics, and other moisture-prone areas of a home. In multi-residential buildings, spot ventilation is most commonly found in the form of exhaust fans, often found in kitchens and bathrooms, as they quickly remove polluted air from their isolated location.
Individual room fans are another example of spot ventilation. Portable models can be placed on the floor or on a table, and mountable units can be permanently installed on a wall or ceiling to circulate the air in a particular spot or room. Spot ventilation, while effective as a short-term solution, is rarely the sole form of ventilation in a dwelling and is best used as a supplement to additional ventilation systems that will filter the air. Further, spot ventilation may require a significant use of electricity to run constantly.
Whole-home ventilation systems are the most common form of ventilation found in modern housing that use a series of exhaust ducts and vents throughout the home to provide man-made, deliberate ventilation and circulated air flow. These ventilation systems boast the ability to be managed, controlled, and modified entirely by the homeowner, building manager, tenant, or a licensed contractor. Types of whole-home ventilation include exhaust, supply, balanced, Heat Recovery Ventilation (HRV) and Energy Recovery Ventilation (ERV).
In recent years, HRVs and ERVs have become more popular, especially in new builds and for renovations, allowing for proper ventilation without sacrificing efficiency. HRVs recover heat as they ventilate the air. Their primary purpose is to save energy through tempering the air being returned back into the home by using the heat extracted from the air that is exhausted. Ideal for some dwellings, an HRV system does not recover energy in the cooling season, and also extracts but does not recover moisture, therefore drying the air and requiring a humidifier to replace the lost moisture in addition to a condensate drain, and in some cases, a condensate pump. Because of this, HRV systems are often not the best option for multi-residential buildings which would benefit more from an ERV solution. ERVs recover both heat and cooling energy, tempering with heat in the winter and cold in the summer while also capturing moisture and helping to maintain comfortable relative humidity in the units. ERVs are a year-round stand-alone solution and comfort enhancer ideal for MURBs. With proper ventilation in and out of the home, you can expect the indoor air quality to improve and residents will be able to breathe and feel better.
ERVs and HRVs can also be uniquely beneficial to the geography of the dwelling. For example, Panasonic’s Intelli-Balance ERV is specially engineered for use in any North American and cold climate zone, providing a tempered air supply, humidity control, and a balanced amount of exhaust to help maintain balanced, positive or negative pressure throughout the home.
The foundation of a healthy home
The importance of indoor air quality on overall wellbeing cannot be stressed enough. The quality of the air inside our homes and other buildings often gets overlooked – you can’t see the problem so why look into a solution? However, the benefits of ensuring a dwelling has the best indoor air quality can vastly improve the health of the inhabitants and stop potential side-affects associated with poor air quality. With technological advancements in the ventilation space, we are able to change the standard of indoor air quality for future generations to build healthy home and MURB environments regardless of budget or dwelling type.
About the author
Kevin Smith is the General Manager of Panasonic Canada’s Life & Device Solutions Division. For more information, visit: https://na.panasonic.com/ca/home-building-solutions/ventilation-indoor-air-quality/.