Cool roof, bro. I say that any time I see Tesla’s , which enjoys prominent placing alongside the carmaker’s EVs on its . It really is a cool roof, intended to pair perfectly with the in your driveway. But and homeowners are running into installation costs much higher than those quoted by Tesla, reports.

We briefly covered this in , but the problem has since received more coverage, and I think it sheds light on the most important part of this latest wrinkle in the Tesla fabric. Namely, Tesla knows it has seriously underestimated the cost of its Solar Roof installations, and it’s passing that cost on to homeowners who were at some point entranced by the slick marketing.

Musk ceded that the company has failed to accurately account for the cost of installing its Solar Roofs during an earnings call this week, as goes on to explain:

It would later be revealed that the company had underestimated the complexity of some of the roofs. Tesla CEO Elon Musk admitted as much in an earnings call on April 26th, saying that the company had made “significant mistakes” in how it calculates the installation costs. Tesla tried to soften the blow by offering some aggrieved customers free Powerwall home batteries if they renewed their orders.

Those “significant mistakes” Musk admitted to ran up to five figures in some cases, such as that of one Texas homeowner spoke to who was initially quoted $69,000 for a Solar Roof from Tesla, only to see the price increase by $35,000 to a grand total of $104,000. He canceled the roof.

And while many homeowners expected some price increase going into this — insert obligatory joke about flakey contractors here — not too many people expected the final cost to be a full third or even one half as much on top of their initial quote.

To ameliorate the price increases, Tesla offered “free” to some folks. These are optional batteries that store energy gathered during daylight hours, increasing the efficiency of homes with Solar Roofs and providing back-up power during outages. I’ve put the word free in quotation marks here, because the cost of the Powerwalls may as well be included in the highly adjusted prices the homeowners are seeing.

Powerwalls, Solar Roofs, Solar Panels. All of these are incredibly cool ways that Tesla uses to deliver on the promise of its environmental ambitions alongside its successful EVs. Still, these unwelcome price hikes are some Tesla drivers and confirm to others that Tesla, on average, is not bringing EVs and renewables to the massesbut mostly to “those who don’t count their money.”