Some people believe in the slow, steady approach to change. Others say “go big”! Zero energy retrofits may require the latter. Making a dozen small improvements over time may be less practical than taking one large leap. This is the idea behind Energiesprong, literally “energy leap.” Originated in the Netherlands, the idea is gaining traction in the United Kingdom, France, Germany and now the U.S.
The big leap takes cold, uncomfortable, mid-20th Century townhomes and completely converts them into zero energy homes in as little as one week. Prefabrication is a key element of the process. Wall panels are made offsite and craned into place. Old windows are replaced. A modular mechanical pod containing space and water heating equipment attaches to an outside wall. In this video, notice the thick panels, external utility enclosure and the pre-installed PV mounts. The resulting transformation was both rapid and profound.
In Europe construction efficiency is increased because much of the housing is two-story rowhouses. This common housing design allows standardized components to be made off-site using industrial methods. Most of the work is done from the outside of the building. Even the window replacement requires only that furniture be moved a few feet out of the way. The occupants remain in their homes throughout the process.
Energiesprong also exhibits an interesting business model. Even though the package contains many different components from wall and roof panels to high-efficiency water heaters and solar panels, one provider is responsible for the whole retrofit. In the same way that consumers buy a computer or automobile from a single “manufacturer,” customers buy a package of materials and labor from a single business entity. That single provider also provides maintenance and warranty service.
The improvements are free to occupants. Instead of paying $2200 each year for energy bills, they pay exactly the same amount to their landlord, a social housing corporation. This reliable cash flow facilitates a large up-front investment by the housing agency with little risk.
The model has also been successful in driving down the price. Largely the result of experience and large volume, the price for Dutch projects that has dropped by roughly 40% since the program started. So far, 1000 units have been completed toward a goal of 111,000. EnergieSprong UK recently announced a $3.9 million grant from the European Commission for development of a British version, which hopefully will not be hampered by Brexit.
The Rocky Mountain Institute brought the idea to the U.S. and would like to serve as a service integrator in collaboration with the Net Zero Energy Coalition. The Carbon Neutral Cities Alliance organized a meeting this month to investigate ways to modify the Energiesprong concept to U.S. market conditions, climates and energy prices. These groups will bring together manufacturers of energy efficient HVAC equipment, solar devices, windows, and insulation along with large scale contractors, real estate developers, housing agencies and big-city governments. According to Martha Campbell, a manager at RMI, the meeting revealed deep interest and set the stage to develop the idea further.
“We are more focused on the process rather than on a specific solution,” said Campbell. “RMI in partnership with the Net Zero Energy Coalition has been asked by industry and various other stakeholders to serve an organizing role in the value chain. This involves coordinating the i key players and elements necessary to assemble an integrated offering, including the envelope, mechanical, financing, and a performance guarantee.” After developing and documenting the process, it can be applied to other locations and situations.
On the technical solution side the key is combining a wide range of energy saving measures into a single package, so that the interactive effects of various measures are captured. Bundling also allows measures with higher financial returns to support those with lower returns at the same time squeezing more efficiency out of the building. Bundling is a function of an integrator who applies industrial methods that increase scale and efficiency, much like an auto manufacturer merges thousands of components into a sophisticated machine. To support this integration manufacturers will have to develop products targeted for the performance and price-point needed to make the project work. An integrated package of economically-attractive, high-performance measures compels building owners to strive for a higher level of overall performance.
“Solar is a game changer, specifically when you consider its interactive effects with an electrified solution (i.e. electric hot water, heating and cooling)” said Campbell. “ Air source heat pumps are also extremely economically attractive when combined with solar.”
While the housing institutions and business practices may differ from the U.S., the Energiesprong approach offers an attractive model for large-scale, full-speed-ahead zero energy retrofits. With a can-do American attitude, these large leaps are possible and on the verge of being available from a contractor near you!