Passive House: An Aggressive Standard to Reduce Energy Consumption
“If we want to achieve the 80 by 2050 goal set by Major de Blasio under OneNYC, we need to do more than talking. We need to start increasing the energy efficiency of our buildings,” states Maya Ezzeddine, manager of New York Passive House. “The passive house standard is one method to aggressively meet the climate crisis carbon initiative while maintaining a comfortable and affordable built environment.”
Passive House philosophy was first developed by the Passive House Institute (PHI) in Germany around 1990. It has since become an international building strategy, now used in the design of numerous New York buildings. Its strict performance requirements aim to reduce the ecological footprint of buildings. If followed throughly, up to 90% of the energy used to heat and cool buildings can be reduced. This number is significant in the discussion of climate change, especially when 75% of New York City’s greenhouse gas emissions come from its buildings.
What is it that makes passive house so efficient? Building orientation, massing, insulation and heat recovery are important design variables taken into consideration. Incorporating these strategies in the original design process allows for the return of maximum energy and economic benefits. However, passive house becomes extremely useful because it can also be adapted to retrofit existing buildings. Due to the large existing building stock in cities like New York, retrofitting may be a considerable option.
A building designed to passive house standards utilizes an airtight envelope and a mechanical air ventilation system to control the influx of filtered fresh air in its living spaces. This methodology eliminates the need for large heating and cooling systems, using less than a quarter of the energy of a traditional building. Aside from environmental benefits, the comfortable and healthy living conditions provided by passive house are often advertised. Its insulation techniques allow a constant interior temperature to be maintained, an important capacity for areas of extreme climate, while simultaneously eliminating all exterior noise.
“You feel the difference of a passive house as soon as you walk through the front door, especially in a noisy city like New York,” highlights Ezzeddine. “All exterior elements are removed to provide an ideal interior environment.” It’s important to note that while the term may be passive house, this design standard is not limited to residential structures. House is merely a metaphor for any building type.
Surprisingly, the comfort and low energy bill provided by passive house does not come at a high cost. It is affordable in both construction and maintenance during occupancy. The estimate additional cost is at most around 5% to 10% of the cost of a traditional building. However, the reduced energy usage allows a return in investment over a short period of time. The long life span and lower energy costs make passive houses affordable in the long term.
Unlike other sustainable design standards like LEED, the goal of Passive House is to have a high performing building. The buildings’ energy balance is calculated through the Passive House Planning Package. Calculating the heat losses and gains enables its energy levels to be kept within the passive house standards. This is a necessary criteria to earn the the Passive House certification provided by PHI.
“Once the energy usage of buildings have been reduced, renewable energy sources can now be utilized to work towards net zero energy,” points out Ezzeddine, highlighting the inefficiency of using renewable energy sources on buildings with high energy consumption and carbon emissions. In a traditional building, the benefits provided by renewable energy sources are instantly eliminated by its operation. However, renewable requirements become more affordable and achievable when a building’s energy demand is minimized through the passive house strategy.
“We’re attending community board meetings to pass a policy on Passive House standards. Imagine if more buildings in New York were using 90% less energy. Meeting the new 80 by 2050 goal would become realistic and achievable.”
