I suggest we have a tread for more detailed discussions of the Solar Roof product. TMC discussions have revealed that consumers may have difficulty properly valuing a solar roof. Consequently, Tesla investors may well have difficulty valuing this product line as well. So there is much that needs to be clarified. Here are a few questions to get us started. First question, what is the efficiency of the active portion of a solar roof? The W/sqft = Efficiency*92.9. So 20% implies 18.6 W/sqft. Unfortunately, Tesla's Solar Roof estimation tool does not seem to give solar value numbers compatible with 18.6 W/sqft. Second question, how do we separate the cost of the roof from the cost of solar and the cost of storage? The marginal cost per square foot of solar is $31 = $42 - $11 before ITC, or $18.4 = $42*70% - $11 after 30% ITC. Here we assume the whole roof will be installed with either active or inactive Tesla tiles, so marginal is just the incremental cost of choosing active over inactive. Third question, how does the Solar Roof cost of roof compare with other roofs? Forth question, how does the Solar Roof cost of solar compare with other solar? If the active portion is more that 18.6 W/sqft, then the marginal cost of solar is just $1.67/W before ITC and $0.99/W after 30% ITC. This is highly competitive even with utility scale solar. Too good to be true? Fifth question, how does inclusion of Powerwalls impact the economics of the solar roof and the optimal portion active? What is the value of storage? My utility offers no feed-in-tariff or net energy metering, and the Tesla estimation tool shows that adding Powerwalls is essential to optimizing the value of solar.