No PV at this time

Here's why not:

• PV technology is improving rather drastically these days. A system like this might cost a lot less in a few years.
  
• Our actual energy cost is about 12¢ per kWh right now, making this system take practically forever to pay off unless we start consuming lots more energy. A similar argument explains why I don't grow corn.
  
• The vendor/installer is unclear how many roof membrane penetrations it'd take to install the array on our flat roof, but it's a whole lot. This will invite leaks and make future roof replacement much more complicated.