Passive House: Is it Worth the Upfront Cost?
Passive House-certified projects have grown in popularity in recent years, but do the benefits outweigh the additional costs?
When building a new home, the material selection and design will impact the energy bills, house durability, and indoor air quality for many decades. Going beyond code requirements for home insulation, air sealing, and heat recovery ventilation saves energy and enhances occupant comfort.
Unfortunately, these features can also increase the project cost. Although there are many advantages to building to the Passive House standard, is it worth the additional upfront cost?
What is Passive House?
Passive House is a rigorous German building standard for energy efficiency and includes criteria for energy demand and airtightness. Passive House–certified projects are up to 80 percent more efficient to heat and cool than projects built to the minimum code requirements. Passive House–certified components, including windows and heat recovery ventilation systems, help builders and designers meet the Passive House standard.
Certified Passive House buildings now account for 2 million square feet of building space in North America, representing a threefold increase over 2015, according to a study by the Pembina Institute. Several jurisdictions have policies that support Passive House and other high-performance construction methods, and a growing body of professionals have been trained in Passive House design and construction.
Does it add to construction costs?
Because Passive House construction typically requires triple-pane windows, generous amounts of insulation, and heat recovery ventilation, there is often an increased cost associated with constructing the home, especially in cold climates. Keep in mind that building codes vary by location, so it is difficult to anticipate the exact price premium. Also, consider that the load requirements for the heating and cooling system are greatly reduced or possibly eliminated, cutting some costs.
For example, Belfast Cohousing & Ecovillage in Midcoast Maine features 36 units built to the Passive House standard. Despite its location in a cold climate, the homes feature a modest electric baseboard heating system and Zehnder heat recovery ventilation system.
Most new homes in the area require a far more extensive heating system yet contain less expensive insulation, windows, and doors. Alan Gibson, a principal of GO Logic, the firm that designed and constructed the homes, estimates that making these homes satisfy the Passive House standard added 7% to the project cost.
There are, however, examples of homes built to the Passive House standard that don’t have a higher upfront cost, such as this home in Ireland. Although the construction costs may be higher, the heating and cooling costs are 40%–90% less, resulting in decades of cost savings.
What are the benefits of Passive House?
Although the energy costs associated with a Passive House are significantly lower, many of the other benefits are harder to quantify. Heat recovery and energy recovery ventilation systems promote indoor air quality by continuously supplying fresh, filtered air to the living spaces while exhausting stale, contaminated air from the bathrooms and kitchen.
Heat is transferred from the exhaust air to the intake air, lowering energy bills.
By contrast, most conventional homes rely on gaps and cracks for ventilation, but heat isn’t captured before the air leaks out of the home, and it is difficult to control the quality of the incoming air. For example, contaminants can enter the home through an attached garage or from a musty basement.
“Indoor air quality is an important part of the equation [when deciding to build to the Passive House standard],” says John Rockwell, a technical sales engineer for Zehnder America. “If a family has a child with respiratory issues, of course, it is well worth it.”
Zehnder heat recovery ventilation systems are Passive House certified and have filters that can remove pollen, dust mites, mold spores, and even bacteria. The systems also remove excess humidity, which can prevent mold growth.
Simple decisions at the beginning of a project will impact the comfort, air quality, and energy bills for years to come. Health, environmental, and comfort advantages are hard to quantify but can are priceless to many families.
Image credit: Jeffrey Mabee of Belfast Cohousing & Ecovillage