• Tesla continues beta-testing on live homeowners, moves to fifth version of integrated solar roof
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Clean energy journalism for a cooler tomorrow

Tesla continues beta-testing on live homeowners, moves to fifth version of integrated solar roof

Elon Musk promised that 2019 was going to be the year of the solar roof. It was not. Neither was 2020, and 2021 doesn’t appear too promising.
By Eric Wesoff

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Building and installing a residential roof with integrated solar is really difficult. Photovoltaic panels and roofing play very different roles, and combining the two typically compromises both — and at a premium cost. Tesla has demonstrated this in the false starts it has made with its still-in-development solar roof product, now on its fifth major design revision since its 2016 introduction.

The memo below went out late last month to contracted Tesla solar roof customers. It details a design change replacing the non-solar roof tiles (historically made of glass) with a steel roof tile on an [expanded polystyrene] support,” according to a source familiar with the matter. The source suggests that this will make it difficult to create a seamless aesthetic integration when new and under long-term weather exposure.” The source attests that other serious design changes” have also been made.

Your humble narrator has seen enough Tesla solar roof tile installations on houses around Silicon Valley to make some observations:

  • A standard shingle roof remove-and-install process typically takes eight hours over two days. The Tesla installs I’ve tracked were running ten days to two weeks and requiring a team of five to six people, with additional personnel brought in to install storage and electric. Perhaps the metal tiles will help improve installation time.
  • The Tesla solar roofs are subjectively better-looking than the composite shingles they are replacing. In some cases, they are better-looking than the house they are installed on. Mismatched metal tiles might change that.
  • Tesla has been targeting simple shed or gable roofs with minimal roof features or other protrusions. The metal tiles might expand the pool of eligible homes.
  • No microinverters or optimizers are being used.

Weddle & Sons Roofing completed and filmed a 40-square (4,000-square-foot), 15-kilowatt Tesla solar roof installation near Topeka, Kansas last year. The time-lapse video covers four days of installing the PV tiles, glass tiles and flashings. The tear-off of the existing roof and dry-in with double-layer Firestone underlayment took one day and is not recorded.

The photo below shows a Version 3 install that was documented by the owner, along with real-time solar output and specs. This installation includes two Tesla battery units and three inverters, according to the homeowners. The garage is also equipped with tiles.

While U.S. residential solar installations doubled from 2014 to 2020’s 3 gigawatts, Tesla’s residential solar deployments have tumbled by half in that same time period. Tesla’s fourth-quarter 2020 solar deployments did show some signs of life with 86 megawatts deployed, but by any measure, the company is no longer a leading player in residential solar.

The actual number of Tesla roof tile installations is well under 1,000, according to our sources, and far below Elon Musk’s aspirations. We would reach out to Tesla’s public relations group in the U.S. to confirm solar-roof volumes and ramp-up timing — if Tesla had a communications group in the U.S.

There are a number of experienced building-integrated photovoltaic designers and installers operating today, such as GAF Energy, CertainTeed, ArteZanos and Forward, but BIPV remains a niche market for custom roof designs on expensive homes in regions with generous solar subsidies.

Article image credit: Manny Becerra

Eric Wesoff is the executive director at Canary Media.