On Sunday, September 13, 2015 at 9:15:16 AM UTC-5, taxed and spent wrote:

Your first mistake was buying your home without knowing what the deal is.

Your second mistake was agreeing to anything with your neighbor.

Your third mistake was not checking your property records to see what the
deal is, hopefully there is something documented.

Your fifth mistake is not taking a mathematical approach to this.

Your sixth mistake is thinking some sort of measurement to figure out actual
costs.

Your seventh mistake is not considering maintenance costs in addition to
electric costs.

....your 1st mistake...not having a 4th!