The Tesla solar roof is building up. CEO Elon Musk shared images on his Twitter page Wednesday of the renewable energy system installed on a house in San Jose, California. The product forms part of Musk’s bold house of the future vision demonstrated in 2016, which included a Tesla Model 3 electric car in the garage and a Powerwall 2 battery storing solar energy for a complete clean energy system.

A Twitter user called “Toblerhaus” shared images of an installation designed to cover her household’s needs, with active panels for about half the roof and the other half dummy tiles to provide 9.9 kilowatt-hours of power. Installation took around three weeks total. Tesla’s calculations place the price of a solar roof at around $21.85 per spare foot, making it an attractive prospect for homeowners looking to jump into solar. The tile glass itself comes with an “infinity” warranty, with the power generation warranty lasting 30 years. The end result is a sleek roof that ditches the add-on panels of yesteryear.

The Tesla Solar Roof installed. Toblerhaus/Twitter

The combination of active versus dummy tiles is key to offering a competitive roof price. Glass tiles without solar elements cost around $11 per square foot and solar tiles cost $42 per square foot. Tesla’s $21.85 figure comes from an assumed rate of 35 percent solar tiles, but it claims most houses will only use about 40 percent solar tiles on their installations.

The company started production of the tiles at its Buffalo factory last November, rolling out initial tiles in January. The textured style pictured above rolled out alongside an alternative smooth style, and the company is expected to launch Tuscan and slate styles further down the line. All four tiles are made of tempered glass three times stronger than slate or asphalt, and anti-ice wires similar to the ones used in windshields defrost the tiles in colder conditions.

With Tesla also ramping up production on the $35,000 Model 3, Musk’s vision of renewable energy at competitive prices is becoming a reality. Over the coming year, Tesla will seek to ramp up production to offer these products with decreasing delivery waits.

While the user is still waiting for clearance from the Pacific Gas and Electric Company to flip the switch, it won’t be the first installation to go live — both Musk and Jeffrey B. Straubel, the company’s chief technology officer, have been using the tiles on their own houses since August 2017.