<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>kcorbitt</author><text>Energy prices have been mostly flat relative to inflation for 40 years, and there&amp;#x27;s a reasonably good chance that they will start dropping appreciably (at least during peak daylight hours) as solar continues to make major inroads.</text><parent_chain><item><author>Reason077</author><text>Energy prices, and thus savings, are certain to increase over that 30 years too. Quite likely at a rate exceeding inflation.</text></item><item><author>pedrocr</author><text>&amp;gt;If I put that same $40,000 in an index fund that got the stock market&amp;#x27;s historical 7% average, and waited 30 years, I&amp;#x27;d have $308,000.&lt;p&gt;Are you doing the math all in present dollars? Because the return is 7% after inflation but &amp;gt;10% before. So you&amp;#x27;d have &amp;gt;500.000 in 2047 dollars. In this case it&amp;#x27;s important to do that adjustment because you&amp;#x27;re doing an investment upfront for payoffs over 30 years so the value of money adjustment is extremely important. It should only make your case stronger though if you haven&amp;#x27;t done that yet.</text></item><item><author>atourgates</author><text>I don&amp;#x27;t really see the selling point, or value here.&lt;p&gt;Tesla&amp;#x27;s calculator estimates $40,500 for a roof that generates half our power needs, and should provide $20,400 worth of energy over 30-years.&lt;p&gt;Add in a PowerWall and federal tax credit, and I&amp;#x27;m still losing $15,400 over 30-years.&lt;p&gt;If I put that same $40,000 in an index fund that got the stock market&amp;#x27;s historical 7% average, and waited 30 years, I&amp;#x27;d have $308,000.&lt;p&gt;To put it in another perspective, the last estimates I got for a solar system that covered 100% of our average power needs came in at $32,000 installed, before the same $11K tax credit that Tesla includes in their calculations.&lt;p&gt;So, I could pay under $20,000 for a &amp;quot;traditional&amp;quot; solar system that covered 100% of our energy bills, or $40,000 for a Tesla solar roof that covered 50% of our energy bills.&lt;p&gt;That&amp;#x27;s quite literally half the value, at twice the price.&lt;p&gt;If I put in a traditional solar system tomorrow, it would pay for itself in year 9.  If I put in a Tesla solar roof tomorrow, I&amp;#x27;d still be out $15K at year 30.</text></item><item><author>blakesterz</author><text>Yikes. I just signed a contract for a new roof here last month, it&amp;#x27;s going to cost about $12k. Just did the estimate for the Tesla Solar roof... $80,300, so $87k if I want the battery too. I can barely afford the $12 right now, the $80 is just so far over it&amp;#x27;s not even close, even with how much I save over the years in electricity.&lt;p&gt;That being said, I love these things, so hoping it gets cheaper in the coming years.</text></item></parent_chain></comment><story><title>Solar Roof</title><url>https://www.tesla.com/blog/solar-roof</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>SystemOut</author><text>Solar leases use the 2% inflation rate too as a way to make them look more attractive (as does the solar roof calculator) but in reality electricity hasn&amp;#x27;t been getting more expensive at that rate.</text><parent_chain><item><author>Reason077</author><text>Energy prices, and thus savings, are certain to increase over that 30 years too. Quite likely at a rate exceeding inflation.</text></item><item><author>pedrocr</author><text>&amp;gt;If I put that same $40,000 in an index fund that got the stock market&amp;#x27;s historical 7% average, and waited 30 years, I&amp;#x27;d have $308,000.&lt;p&gt;Are you doing the math all in present dollars? Because the return is 7% after inflation but &amp;gt;10% before. So you&amp;#x27;d have &amp;gt;500.000 in 2047 dollars. In this case it&amp;#x27;s important to do that adjustment because you&amp;#x27;re doing an investment upfront for payoffs over 30 years so the value of money adjustment is extremely important. It should only make your case stronger though if you haven&amp;#x27;t done that yet.</text></item><item><author>atourgates</author><text>I don&amp;#x27;t really see the selling point, or value here.&lt;p&gt;Tesla&amp;#x27;s calculator estimates $40,500 for a roof that generates half our power needs, and should provide $20,400 worth of energy over 30-years.&lt;p&gt;Add in a PowerWall and federal tax credit, and I&amp;#x27;m still losing $15,400 over 30-years.&lt;p&gt;If I put that same $40,000 in an index fund that got the stock market&amp;#x27;s historical 7% average, and waited 30 years, I&amp;#x27;d have $308,000.&lt;p&gt;To put it in another perspective, the last estimates I got for a solar system that covered 100% of our average power needs came in at $32,000 installed, before the same $11K tax credit that Tesla includes in their calculations.&lt;p&gt;So, I could pay under $20,000 for a &amp;quot;traditional&amp;quot; solar system that covered 100% of our energy bills, or $40,000 for a Tesla solar roof that covered 50% of our energy bills.&lt;p&gt;That&amp;#x27;s quite literally half the value, at twice the price.&lt;p&gt;If I put in a traditional solar system tomorrow, it would pay for itself in year 9.  If I put in a Tesla solar roof tomorrow, I&amp;#x27;d still be out $15K at year 30.</text></item><item><author>blakesterz</author><text>Yikes. I just signed a contract for a new roof here last month, it&amp;#x27;s going to cost about $12k. Just did the estimate for the Tesla Solar roof... $80,300, so $87k if I want the battery too. I can barely afford the $12 right now, the $80 is just so far over it&amp;#x27;s not even close, even with how much I save over the years in electricity.&lt;p&gt;That being said, I love these things, so hoping it gets cheaper in the coming years.</text></item></parent_chain></comment><story><title>Solar Roof</title><url>https://www.tesla.com/blog/solar-roof</url></story>