Constructing new sustainable projects is all well and good, but there are still many drafty old buildings in use throughout the United States. With this in mind, Snøhetta has teamed up with Harvard's Green Buildings and Cities (CGBC) to create HouseZero. The project involved renovating a pre-1940s building into a new energy-positive office and aims to offer ideas for making old inefficient buildings energy-efficient.

HouseZero also involved Skanska Teknikk Norway and was created as a kind of working laboratory. The idea is that it will be used daily as CGBC's headquarters while being monitored for its efficiency and eventually produce more energy over its lifetime than was used to renovate it.

To bring this about, the once inefficient office space has been retrofitted with a lot of sustainable technology and design. For example, its original HVAC (heating, ventilation and air-conditioning) unit was replaced with a ground-source heat pump, while triple-glazed windows open and shut automatically to help maintain a comfortable temperature.

No artificial lighting whatsoever is used during daylight hours thanks to the carefully-placed glazing and skylights. Additionally, the windows sport sculpted surrounds that offer shading during summer months. The building is topped by a roof-based solar panel array too.

Hundreds of sensors have been installed in the building to track its energy usage and the team will closely monitor its performance year-round.

"The building will adjust itself seasonally, and even daily, to reach thermal comfort targets for its occupants," says Snøhetta. "285 sensors embedded within the building collect almost 17 million data points each day. This data infrastructure enables the building to immediately self-adjust in response to both internal and external variables such as outdoor air temperature or rain, and indoor CO2 levels and air temperature."

It's early days yet and there's still a lot to learn, though the team hopes the project will ultimately demonstrate that an energy-efficient renovation can be preferable to knocking a building down and starting again.

"We hope to prove that HouseZero's approach is replicable," says Harvard's CGBC. "Some of HouseZero's upgrades are solely required to transform the building into a functional office for up to 20 researchers and staff, but most enhancements to the existing building are viewed through the lens of the renovation market. The CGBC believes that the best ideas should be transferable to other building owners as a recipe for significant energy and carbon use improvements to their existing structures without costly or wasteful tear-downs.

"While a building owner may not be able to implement every aspect of HouseZero, applying one or more of its components could positively impact its environment, the health of its occupants, and building operating costs."

Sources: CGBC, Snøhetta

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