EpiPHany Corner | PH Value Proposition: EnerPHit for Existing Buildings

Passive House California advocates for the awareness, understanding, and application of the Passive House standard.  Most of the time, the focus is on the design and construction of new Passive House buildings (single-family, multifamily, and a wide range of other types). The high-performance of Passive House provides significant benefits in terms of energy efficiency, comfort, indoor air quality, durability, and resilience. Clearly, a smart and responsible choice for owners, occupants, and the planet. However, new buildings constructed each year represent only a small fraction of buildings in use across America.

By any measure, the “unprecedented action” required to limit global warming must include the dramatic reduction of energy use associated with the operation of existing buildings. EnerPHit is the Passive House standard for retrofitting buildings. The chart below is from a case study associated with the retrofit of a 1970s three-unit apartment building in a temperate climate (Winter highs average around 60° Fahrenheit (F) and lows around 30° F, while in Summer, lows average around 70° F and highs can reach 100° F.

(Note: The area is 312 square meters (the building is in Greece) which converts to 3,358 ft2. The case study can be found here).

Three-part EpiPHany: The potential impact of retrofitting existing buildings:

1.     The US has over 100 million buildings and single-family homes represent about 90% of the total number of buildings and 60% of the total square footage. The approximately 1.5 million new buildings completed annually is, as noted above, a small fraction of the total buildings in operation. Addressing energy efficiency in existing buildings offers an exponentially larger scale of impact.

2.     Building to the Passive House standard dramatically reduces operational energy required when compared to new buildings that are simply code compliant. However, existing buildings were constructed to less stringent codes from decades ago. Retrofitting to the EnerPHit standard is likely to yield even more impactful energy reductions.

3.     There is a significant carbon impact to demolishing and disposing of an existing building. The replacement of that building adds the embodied carbon associated with the materials, components, and construction process. Therefore, retrofitting an existing building to EnerPHit standards will nearly always result in a substantially lower carbon impact than removing and replacing that building.
(Note: PHN’s PHribbon (here) enables the calculation and informed decision-making regarding the embodied carbon associated with new construction or a retrofit.)

And a recommendation:

If you are a building industry professional with an interest in high-performance retrofits, I suggest “The Power of Existing Buildings” by Robert Sroufe, Craig Stevenson, and Beth Eckenrode. It is a state-of-the-science book on how to “save money, improve health, and reduce environmental impacts” of existing buildings — and new buildings as well.

Author: Jay Gentry