This story is paired with a related story about Moab’s first passive house.
The passive building standard is about minimizing the need for energy as opposed to counting how many solar panels or wind turbines a house has.
Passive houses achieve low energy needs primarily by focusing on the airtightness of buildings, which can significantly reduce a building’s need for artificial heating or cooling.
What makes the idealized passive house “passive” is that it can hold heat efficiently enough that the occupants of the house are the only heating elements needed. In reality, passive house certifications are less exacting, though only slightly; passive houses consume 75% to 95% less energy than typical houses.
Although it might seem contradictory that an airtight building would also be well-ventilated, passive houses do achieve both. They do this typically using ventilation technology known as energy recovery ventilation; these systems circulate air from indoors to outdoors, swapping the temperatures of the two in the process.
In cold months, this process warms the outdoor air as it flows inside, refreshing the indoor air quality in the process, and in hot months, it cools the outdoor air.
The result is housing that, as its name suggests, exists passively in its environment, drawing little to no energy for climate control, producing zero emissions from natural gas or other fossil-fuel heating, constantly providing fresh air and heating occupants in cold months the same way a sweater would: By insulating body heat.
How is ‘passive’ different from ‘net-zero’?
A building considered passive requires little or no energy to maintain an acceptable climate inside; it is a standard that considers energy needs. On the other hand, net-zero buildings generate as much energy as they consume, for example, using solar panels, geothermal heating and other alternative energy sources; it is a standard that compares energy needs to on-site energy production.
The two standards exist symbiotically. A passive house of the same size as a non-passive house would, for example, require fewer solar panels to be net-zero compared to its non-passive counterpart.