Green building concepts have come a long way. As architects, designers, and builders gain access to better tools that help push the limits of construction energy efficiency; we see longer strides made towards more mainstream adoption of green building standards. One such standard that is coming of age is passive houses. The concept of passive houses was first mooted in the early eighties when the idea of green building was still in its infancy. Today, the concept is well entrenched with over 25,000 houses and buildings across the world qualifying as passive houses.
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We recently caught up with Toyin-Ann Yerifor, an architectural consultant focused on exploring new and innovative ways to design with reduced impact on the environment to explain what passive houses are and their benefits. She holds an MSc in Architecture (AEES) from the University of East London, an MBA from the University of Northampton and an MSc in Computer Science and Engineering from the Université Grenoble Alpes.
What is a Passive House?
First, what is a passive house? Toyin-Ann explains: A passive house is any building that adheres to rigorous energy efficiency standards. The term passive comes from the fact that the building’s energy efficiency comes from its passive structures, which include the roof, walls, windows, doors, and floor. By radically improving the building’s insulation and energy conservation features, it is possible to reduce its heating requirements by up to ninety percent. As such, passive housing as a standard is focused on helping reduce the energy requirements of buildings through insulation, and by extension, their overall energy footprint.
When you reduce a building’s energy footprint, says Toyin-Ann, several benefits accrue, including environmental, health, and cost efficiency benefits.
Environmental Benefits of Passive Houses
According to the International Energy Agency (IEA), “energy efficiency is the first fuel of a sustainable global energy system. It can mitigate climate change, improve energy security, and grow economies while delivering environmental and social benefits.” Passive houses deliver on this mandate superbly, says Toyin-Ann Yerifor. One of the biggest challenges traditional buildings face is energy loss. When a building easily loses energy in the form of heat, it takes burning more fuel to heat the building. When this happens, overall energy consumption goes up, which is bad for the environment because a major portion of heat generation comes from burning fossil fuels. When buildings are radically energy efficient, on the other hand, less energy is required, and so fewer fossil fuels need to be burned.
While this is the macro view of the environmental benefits of passive houses, are there any micro benefits of investing in this technology? Here are two, says Toyin-Ann Yerifor. First, think of the air quality that comes with less energy consumption. In homes that rely on furnaces, doing away with the furnace improves the air quality in and around the home significantly. Second, sound pollution is eliminated if you no longer need to use a furnace, HVAC units around the home, or any other heat generation and management devices. Essentially, says Toyin-Ann Yerifor, passive houses reduce the need to burden the environment. Through radical energy efficiency and self-sufficiency, passive house buildings become a part of the environment and not just an addition to it.
Health and Comfort Benefits
When most people hear about passive houses, they imagine living in a sealed paper bag. That thought can be quite disheartening because issues of quality of air, air adequacy, and comfort come to mind. Although the idea behind passive houses is energy efficiency through a tightly sealed envelope (building), this does not mean health and comfort are compromised. Take air quality, for instance. Most people consider opening a window the best way to guarantee air quality in a room. Now, passive houses rely on closed windows to ensure no heat escapes, which presents a dilemma. Passive houses address this dilemma well, says Toyin-Ann Yerifor.
Although you can open a window in a passive house, even if you do not, the heat recovery ventilation system ensures there is enough quality air circulating the house. Regarding comfort, passive houses maintain a comfortable temperature regulated by the passive heat sources in the house like appliances, body heat, and lighting. Also, they tend not to have cold spots or hot spots, which is often the case with traditionally heated homes. Through rigorous design standards afforded by tools such as the Passive House Planning Package, homes built on the passive house standard adhere to comfort standards as rigorous as the energy efficiency standards stipulated.
Cost Efficiency Benefits
Cost efficiency is at the heart of the passive house concept. When a building is exceptionally well insulated, it can use as little as 10 percent of its regular heating energy requirements. This, of course, also significantly reduces the costs associated with heating the building. So, how does the passive house concept achieve such a radical reduction in energy needs? The answer is insulation, says Toyin-Ann Yerifor. Passive houses rely on extensive insulation to gain this level of energy efficiency. Why is insulation so effective?
Traditional buildings lose a lot of heat through the roof, walls, floor, doors, and, most of all, windows. With a passive house, each of these structures is carefully designed and built to ensure close to zero loss of heat. When you look at the thermal scan of a passive house next to a traditional house, you’ll notice the passive house is almost entirely blue, meaning there’s close to no energy loss. The other building is close to all red, meaning it is losing a lot of energy. This level of energy conservation and efficiency is what leads to the massive energy savings that make passive houses so cost-efficient.
Passive houses are a concept that is yet to hit mainstream construction. However, this does not mean it is impractical to build passive houses. What it does point to is the need for better awareness of the concept. Toyin-Ann Yerifor recommends anyone interested in the concept to visit a passive house showcase home to experience its benefits firsthand. She says this is the only way to understand and internalize this breakthrough energy efficiency concept.