The homes actively avoid the direct use of fossil fuels—such as gas for heating—and utilize electric-based systems that enable use of renewables for on-site generation. “We also tend to approach projects with a ‘fabric first’ mentality whereby Koto buildings are designed with high-performance envelopes that limit the amount of energy required for services such as heating, cooling, and lighting,” says Theo.  Photo 9 of 15 in This Prominent U.K. Prefab Builder Is Scaling Up From Cabins to Custom Residences

This Prominent U.K. Prefab Builder Is Scaling Up From Cabins to Custom Residences

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Koto says it designs its home to run on renewables rather than fossil fuels. "We also tend to approach projects with a ‘fabric first’ mentality, creating high-performance envelopes that limit the amount of energy required," says Dales.