The long awaited, post-solar water heater installation, electric bill has finally arrived. Unfortunately, Chelco has changed their format on me so I can’t get a really good month to month comparison. Typically, they have a chart that states the temperature highs, lows and averages this month, last month and one year ago. That was the part that was missing. Anyhow, we used 1140 kwh last month compared to 1420 kwh the month before, though last month was for a 29 day period and the previous month was a 31 day period. It appears that the solar water heater may save an estimated $20-30 a month at the current rate of electricity. That’s assuming that August was a hotter month than July, therefore more electric was spent on cooling. Next month’s bill should give me a better idea of how much we are saving. The next goal for the house is to investigate converting my heating and cooling to geothermal or swapping out my 12 seer unit w/ one of the higher 18+ seer units. Ultimately, I’d like to be below (much lower) 800 kwh a month, then a 2-3 kw PV systems would start to look appealling in terms of an altenate energy source.
The system I had installed was a 40 gallon ProgressiveTube passive solar water heater. The cost was $3,500 which included the parts, labor (closest certified contractor was 2 hours away) and crane rental. I’ve applied for a state rebate of $500, which was just signed into law in the state of Florida as of July 1, 2006. At the end of the year, I will receive an additional Federal tax credit (taken from my bottom line taxes due) of $1050 (30% of cost of the system). That leaves a balance of $1950, divided by an average monthly savings of $25, means it will pay for itself in 78 months or 6.5 years. Of course, if the cost per kwh were to double, my savings would double and the time to pay for itself would be cut in half. That’s the break down of my solar water heater experience. Keep in mind, my system was retrofitted. The initial cost may have been less if it had been integrated during construction. Another energy saving option would have been to install a PV powered instantaneous water heater. I opted NOT to rip out my perfectly good water heater, also I was on an extremely tight budget when the house was under construction. And there you have it.