I've been working for some time to reduce my electric bill and concluded that the main driver was my very old (5+ years) water heater. I explored several options for hot water (gas, solar, etc.) and finally concluded that from a payback/ROI standpoint a heat pump based hot water heater was best.
Earlier this week I went ahead with the installation and after only 24 hours I have the first data showing my actual savings.
Rather than waiting until the end of the month, I can now (thanks to the new GMP smart meters), go into my GMP account and see my electricity consumption on an hourly basis - all the way up to this morning.
After signing into my account I was able to export my data into an excel spreadsheet and generate a chart showing my hourly kWh consumption for the past few days - and then compare my "old water heater" usage patterns to my "new water heater" pattern.
The resulting chart looked like this:
|Hourly Electric Consumption (click to enlarge)|
The blue line was the day before installation the red line was the day of installation and the green line is today. You can see a dramatic decrease in my base level of consumption.
To calculate my ROI on the water heater I calculated my % savings and was astonished to see that I was saving an average of 80%!
Assuming that this continues, in 1 year i was save $1538 - for a total investment of $1500 (not counting the $300 tax incentive).
My payback period? 1 year, maybe less. The official GE website puts my total savings at only $300 per year, but this wasn't taking into consideration the age and efficiency of my very old electric water heater.
My conclusion? Take a hard look at your water heater and then shop around for the most efficient solution you can find - you may be surprised at how much you can save.