Passive House Design: Building for the Future
Sometimes the future we need is already here –
we just need to recognize it, then muster the courage and determination to live it.
Imagine finding yourself in a beautiful and spacious 2,800 sq-ft, 3 bedroom 2 ½ bath custom home that has no air conditioner or furnace, yet is extremely comfortable year-round despite a climate that boasts brutally cold winters and hot humid summers. In addition, the inside environment is continuously bathed in fresh, filtered air, creating a healthy living space for those with allergies or asthma, or living in an area with poor air quality (including the increasing number of regions impacted by wildfire smoke hazards).
Such a house already exists, and for the past 11 years has been home to a family in Cleveland, Ohio. The PNC Smarthome is a stellar example of the ultra-energy efficient built environment we need. Built by the Cleveland Museum of Natural History in 2011, the Smarthome is Ohio’s first certified passive house. Initially serving as an exhibit on ultra-energy efficient design that attracted and engaged a record number of new visitors, it was moved a few months later from the museum grounds to a nearby vacant lot and sold to a family who fell in love with its unique features. Over the past decade the smarthome has performed spectacularly, providing an ideal indoor environment throughout Cleveland’s hot summers and icy cold winters with only a small, energy-efficient electric heat pump on each floor – it has no furnace or air conditioner. The design echoes the architecture of the neighborhood and it’s easy to live in – windows can be opened on nice days, and no special maintenance is required. The house was sold last year by the original buyers for 60% above their purchase price.
As a bonus these buildings also provide healthier indoor spaces for living and working.
Near-zero carbon emission, healthy indoor environment, and excellent investment for only about a 10% premium over the cost of building the same house to current building codes – this is the architecture of the future.
As we struggle to reverse course on climate change and mitigate the disastrous impacts that are already wreaking havoc across the globe as a result of our delay in taking action, we face many difficult decisions that will compel us to make significant lifestyle changes and major financial investments. The built environment is an inspiring exception to this. Using passive house methods, we already have the knowledge and the technology needed to construct buildings that use dramatically less energy, create resiliency against the coming onslaught of heat waves and power outages, and decrease carbon emissions – all at relatively small additional cost and without sacrificing comfort, functionality, or beauty. As a bonus these buildings also provide healthier indoor spaces for living and working.
The key ingredients are the most valuable renewable resources we possess – human creativity and determination, inspired and informed by the wealth of our science and engineering expertise. We simply need to spend more time on smart design before we build and invest 5-10% more (and sometimes less) in energy-efficient and sustainable construction to reap a lifetime of better living.
The essential design principles of a passive house building are relatively simple (although the detailed realization of these principles requires careful planning and execution). The house is essentially an enormous thermos – airtight and super-insulated, with no thermal bridges from the interior to the exterior, keeping the interior at an even temperature. These homes typically have a sophisticated ventilation system that provides a continuous flow of fresh, filtered air while transferring heat between incoming and outgoing air, allowing very little heat loss (or gain) in the process. As for windows, these homes use high-performance windows facing south so that in winter sunlight streams in to warm the interior. In summer when the sun is higher in the sky, small awnings are used to block sunlight to keep the house cooler. Finally, a heat pump gets installed that uses roughly the same energy as a handheld hairdryer to provide a small boost of heating or cooling when needed.
Passive House buildings of every type, from single family homes to office buildings, offer multiple long-term benefits that are especially important in economically challenged urban and rural communities already disproportionately impacted by climate change:
- Economic: A passive house consumes up to 90% less heating and cooling energy than a conventional existing building, and up to 75% less than new construction built to code. Utility bills are greatly reduced, a factor that may become even more important in coming decades, freeing up significant financial resources that residents can invest in other areas such as education, healthcare, debt reduction and savings, opening avenues to wealth creation for families.
- Health: The air ventilation system provides continuous circulation of fresh, filtered air, minimizing allergens and pollutants.
- Climate Change: Residential buildings currently contribute about 20% of total U.S. carbon emissions, primarily through energy use. Passive buildings will help to reduce emissions to reach target levels by lowering the energy demand. Equally important, the ability of passive buildings to maintain comfortable interior temperatures with minimal energy input provides much-needed resiliency in the face of deadly heat waves.
- Net positive energy: With the addition of solar panels, passive buildings can become net producers of energy. Installing battery systems (sometimes aided by forward-thinking energy providers offering financial support) will add further resilience in the face of climate change by providing back-up power during outages, while also contributing energy to the power grid during peak times.
There are now over 60,000 passive house projects worldwide, including high-end custom homes, low-cost affordable housing units, apartment complexes, office buildings, schools, and hospitals. Most are in Europe – but not all. Early examples of superinsulated buildings were pioneered in North America in the 1970’s, with similar projects underway in Europe. German physicist Wolfgang Feist developed the passive house standard in the following decade, and the world’s first official passive house project was built in Darmstadt, Germany in 1991. There are now a growing number of Passive House projects across the globe.
Colorado’s first certified passive house was completed in 2016, and more will follow, but the transition to passive house construction is not happening as quickly as it could.
Within the U.S., knowledge of passive house design and its benefits is limited, and there remain misconceptions regarding the difficulty and costs involved. The relatively small cost premium over traditional building is also a barrier for some.
Passive house construction demonstrates that it is possible to significantly reduce our dependence on generated energy from any source without sacrificing comfort, space, beauty, or livability.
As more passive house buildings are constructed in the U.S., awareness will grow and costs will continue to decrease, hopefully accelerating the pace, but we need to do more. Schools of architecture should make ultra-energy efficient design, including passive house, a core required pillar of their curriculum. Cities and communities should require ultra-energy efficient design for all new construction, especially publicly funded buildings. Architects should present the benefits of these design techniques to all clients, and new home builders should demand them. The cost above traditional construction should be weighed against long-term energy cost savings, health benefits, and environmental impact. Foundations, philanthropists, and government agencies should begin to cover the cost premium for low-income neighborhoods and offer incentives for any passive building project.
Passive house construction demonstrates that it is possible to significantly reduce our dependence on generated energy from any source without sacrificing comfort, space, beauty, or livability. Friends of the museum in Cleveland built their dream house to passive house standards shortly after the PNC Smarthome was completed:
“Building an ultra-energy efficient house 11 years ago was one of the best decisions we have ever made. With battery storage added 3 years ago, we are now a net positive producer of electricity. Of equal importance, the home is incredibly comfortable. In a winter climate, having no cold spots makes our comfort level very high. We also are pleased that we could build a home that was both energy efficient and beautiful. Energy efficiency does not need to come with an appearance that not esthetically pleasing.”
Dr. Steven Nissen and Linda Butler, Cleveland, OH
We can, through smart design, build a better future for all of us.
The Institute for Science & Policy is committed to publishing diverse perspectives in order to advance civil discourse and productive dialogue. Views expressed by contributors do not necessarily reflect those of the Institute, the Denver Museum of Nature & Science, or its affiliates.