Hacker News Reader

Comment by kodis | Hacker News Reader

I really love the work that Tesla is doing in this area, and wish them all the luck in the world, but if the estimates in the article are even close ($57K for a Tesla roof, $41K for a tile roof with a small solar panel, $22K for a conventional asphalt roof) it's hard for me to see this being cost effective.

View on HN

It's like any sort of tech: the first version is too expensive and then the price drops some % every year until we all have "supercomputers" in our pockets.

Plain Solar Panel (non roof) installation has gone from $52k to $20k in the last decade [1] which is craziness.

The other aspect of this is longevity. Setting all solar power generation aspects aside an asphalt roof will generally last 20-25 years. Tesla roof tiles appear to last much longer (infinite warranty, etc.) and are maybe more comparable to a slate roof which would be 10x the cost of an asphalt roof.

As a reference point, I grew up in a house built in the 1920s and just confirmed via Google Streetview that it still has it's original slate roof.

1 - https://news.energysage.com/solar-panel-efficiency-cost-over...

20-25 years is at the limit of what I could imagine staying in one house with any certainty. How does the extra longevity justify the cost unless I plan to never ever move again?

resale value?

So you don't have to replace it again before selling it, or take the hit from someone deducting the cost of a new roof off of an offer, the first is typically better for you as a seller. It also adds value to the house in multiple dimensions: they don't have to replace the roof when they sell it, and a solar roof reduces their electric bill.

It goes to the home's value (aka you'd get more when you sell it). I kind of think of it like brick. Brick has a much longer maintenance cycle than vinyl or wood siding.

The is true in theory, but in practice the housing market isn't 100% efficient.

You'll no doubt recoup some of your value, but not all of it.

Part of our bubble is that at times it's been "more than 100% efficient", so to speak.

Witness dozens of TV shows, "You guys had $50K for your reno budget. Your original value was $250K, and you spent $50K and now your house is worth $350K!"

Your example doesn't show excessive value capture for the upgrades in the home. Rather, for the extra 50k in bank loaned money, the buyer is choosing not to engage in renovation for reasons typically related to: inconvenience, time restrictions, lack of vision, etc.

Moore's law is the exception, not the rule.

Does Tesla have any sort of public lifetime estimates?

They are touting an "infinite warranty" for the integrity of the tiles (which doesn't include the electronics portion).

Does the warranty include labor?

Actually, no. Moore's law is really a general trend that is apples to pretty much everything, just with different constants. As our knowledge and tech advances, everything gets cheaper and easier. This is also known as "Economies of Scale".

No. In basically no other industry does "performance" double every two years. Agricultural output doesn't double every two years, drugs aren't twice as effective every two years, and cars aren't twice as fast every two years. Semiconductor manufacturing is the exception, not the rule.

As for the different constants point -- you can model anything as an exponential function with a small enough coefficient. Moore's law is significant because it doubles every two years.

Economies of scale is in reference to mass production (scale). Making 1000 widgets is cheaper than making 10 widgets on a per widget basis. This is fundamentally different from the predictions made by Gordon Moore.

It's also like to point out that Moore's Law hasn't applied for a while now. Ultimately, we'd be at >5nm, and that's nowhere near ready.

In addition to the other replies, a slate roof is nowhere near ten times the cost of asphalt shingles. It's more like 3x, and that's only if you price the cheapest asphalt shingles.

I had a damaged slate roof. Bids to repair it, replacing most of it, were north of $100k. An asphalt roof with 30 year shingles was under $5k. Ten times isn’t enough.

I have a slate roof now, and pay a few hundred a year for replacement of broken skates. For historical-commission reasons, I’m much more likely to do Tesla-style tiles than anything else... and electricity here is 22¢/kWh.

Average cost to replace a 2,000 sf slate roof is ~$30,000. Someone was likely trying to rip you off.

Lifespan is kind of a leading question as many buildings simply are not going to last. Still, the high end for slate is very high. "There is a chapel in England, built during the 8th century, which has one of the oldest slate roofs known. After 1,200 years of service, the moss-covered roof is still in good condition, demonstrating the permanence of the material."

Is slate particularly popular in the US?

In the UK most tiles are made of clay which are cheap and pretty durable. My neighbourhood is Victorian and I guarantee some of the houses here still have their original tiles. Some towns have slate roofs (e.g. the Lake District), but it's more expensive and a local aesthetic/tradition, more than anything else.

Virtually nobody uses shingle roofs. To give an idea of the historic distribution, which is still pretty accurate: http://www.buildingconservation.com/articles/claytile/pic_12...

Replacement prices, for example: https://local.which.co.uk/advice/cost-price-information-roof...

An entire slate roof on a big house is around £12k max. I'm surprised that the difference isn't that much compared to clay, but I imagine most of the cost is labour.

Depends on the style of home (Spanish, traditional, modern, etc). I see clay tile, slate, and asphalt mixed in the same neighborhood pretty frequently. Of course, the higher the home value the less likely it's going to have asphalt (or at least asphalt that looks like asphalt).

They're already backordered. If they lowered the price, they would be even more backordered, but have less money. We won't know what the non-early-adopter price is until a few years from now.

Well, roof work is an endless source of work .. and an endless source of material (before Elon). The material gets better every year .. its the workmanship that doesn't unfortunately, nor do the hazards associated with roof work. At any price, solar still remains a "cut the wire" thing, and the more wires you cut to the house eventually the more "free" you live. That said, it does not surprise me that Elon has this problem .. no matter what his reputation is .. because he delivers on the workmanship.

The idea is that the energy generated makes up for the added cost, so cost of roof - energy savings = less than standard roof.

"A plain-old asphalt roof with panels would run about $22,000"

That's with panels to give equivalent power output. You're essentially paying a $35k premium for a sleeker install.

And what would the effect on property value be for an asphalt roof with garish panels vs. the Tesla option?

Probably depends on the home. I don't think it would add $35k worth of value over the other installation to a home (especially for a typical $200k home). Also, who cares about property value? If you're selling anytime soon after installing either system, you're going to be taking a significant loss because I doubt you'll make it back in added property value. Especially for the Tesla system. Hard to justify to folks, "Yeah, my otherwise standard $200k home has a fancy $57k roof."

Maybe for the bay area where homes are often over $2mm and the desire for such a roof is plausibly high.

Sounds like you figured out what their target market looks like then.

It's definitely an item for the 1% class. I'm not surprised it's "backordered" because it's going to be extremely low supply to begin with.

The roof tiles they use are supposedly 'indestructible' and have a longer life than asphalt shingles.

That being said, I'm skeptical of their claim. Not many things are indestructible when a large hailstorm rolls through.

Don't they have a lifetime warranty? They're at least putting their money where their mouth is.

The drop test shown in the announcement is impressive to me.

This is like the Apple iPhone of solar panel solutions. It looks better than regular solar panels, so those who can afford them, will get them.

I thought they were making this "competitive" with other kinds of tile roofs. Going up against asphalt shingles is pretty ambitious.

Prices will come down as a result of scale and tech advances. And it has been coming down substantially every year

I thought you had to be wrong until I read the article. If people found solar panels garish, unsightly, this would sell like hotcakes. But just the oposite: people will put panels towards the street even when that's not the best angle or side. Like buying Prius over Honda's hybrid because the Toyota is distinctive, people want to flaunt their green.

Maybe this will appeal to people who are green-minded, but live in a conservative area and are ashamed about it.

Being conservative has nothing to do with it. The area of NY I live in right now is extremely conservative and there are dozens of solar panel installations from Apex Solar on homes and businesses.

That means they’ll help to create a new industry, increase competition, drive down prices, but won’t save as much money.

Aren’t we still better off?

Reply on news.ycombinator.com