This is caused by the squeegee being angled incorrectly forcing the water under the rubber blade out into the dry area of the glass or from solution being pushed up into the top edge of the window.
Although there is a slight difference between our original calculation and Teslaâs new oneâlast fall we built in a cost of $6,500, Teslaâs current cost for a Powerwall as part of a Solar Roof installation is $7,000.
Our analysis was based on the estimated cost of 30 years of electricity, but it didnât factor in the value of any solar incentives or rebates. We estimated that the installed cost of a 3,000-square-foot Solar Roof should be no more than $73,500. In their initial pricing announcement, Tesla said it derived its own cost calculations using CR's methodology, and it beat the upper limit we identified by nearly 11 percent, coming in at $65,550 ($21.85 per square foot) for the same example house.