In slightly more than a week, a clever kit of parts can transform an old rental house into a net-zero energy home—one that creates as much renewable energy as it uses in a year—at no extra cost to tenants or building owners.
Net-zero homes are the kind of project that usually cost so much that only the richest, most environment-obsessed homeowners attempt it. But in the Netherlands, a group of innovators figured out how to create a system that could be used on the country’s huge inventory of low-income housing.
The mid-century rental houses, built in townhouse-like rows, all have a similar layout, so construction companies were able to design a system of prefab parts that pop easily on existing properties. A roof covered in solar panels can go directly on top of an old roof, minus tiles. New facades cover the old walls without any demolition. In the backyard, a new cube-shaped energy module holds everything needed for sustainable heat, hot water, power, and ventilation. It just needs to be plugged into the house.