|Estimation and Extrapolation
||[Jan. 16th, 2012|02:52 pm]
Home Effinomics, or Effin' Around the House
Just a couple of days ago, I shared a few bill and usage graphs I was goofing with. After posting, I started poking about on the utility's web site to find what the future might bring. I found a study on proposed rate changes (NB: PDF file) that gives the proposed rate increases for the next three years. It turns out the Seattle Public Utilities District has a bunch of capital improvements to make, and needs the rate to hike to pay for them. They're pretty substantial, these increases.
Just for kicks, I entered these new rates into the spreadsheet I used for the area graph of the billing over time. For use information, I just extracted the use for the last four years as a block. This is also the highest use period in my data, so I'm aiming high. I then gave the unknown rate increases of sewer and garbage an annual 10% increase. It may seem high, but over time it's about average of the increases we've been historically experiencing. Here's the result:
What's missing is the known history to which it should really be compared. I recalibrated the scale on the first area graph to fit this one, and sized them to match. Without the redundant dollar scale, here's what they look like side-by-side:
These future bills strike me as tracking well ahead of inflation, especially the anemic real-world wage inflation The Wife™ and I have experienced recently. It's time to compensate.
One element is out of the estimated data. We've already reduced the level of garbage service, opting for the smallest yard waste can available. So far, so good. Once yard waste starts accumulating, we may rethink this decision. This should reduce the garbage portion of the bill to about $8/bill or more depending on future rate hikes.
As to what to do to drop the rest of the climbing charges, or at least arrest their ascent, I see every penny above the recent past trends as a budget to use as a benchmark. If I can do something to bring the estimated 2014 bill even with the actual 2010 bill, every penny difference and a bit more should go toward that effort. This gives me several hundred bucks to play with.