I can now quantitatively recommend the excellently placed investment in the installation of an electric timer for your electric hot water heater. First let's get a baseline of data to support this statement.
Below is a table of data, the same used in previous charts graphing our electric bills for the past year. I've added a column showing the kWh (kilo-Watt-hour) utilization and a cost in pennies per each.
|Statement Dt||Cost||kWh||Cost / kWh|
As you can see, the cost per kWh has been creeping up. Notice that this is for the past year back into 2009. My wife found a note she'd made in 2004 when we were paying .09 per kWh. That was way back before we used a lot of CFLs, timers, had better windows and power hungry CRTs everywhere and the average monthly bill was right around $100.
Notice the last two rows in the table above. The October bill represents our first month of automatic switching of power. The month preceding that we did our best to manually turn it on and off as we remembered, which was nearly every day but not as precise. The automatic timer is set up to give us morning and evening hot water in enough abundance that we are fine with confining our showers to evening time and getting our wash done during the day. Sometimes these switch where wash is done at night and showers in the morning. No great discomfort is felt on our part.
So, an updated version of our chart (now rendered by Open Office on Mac OSX) looks like this.
Now that, my friends, is quantitative evidence of a money saving trend, which justifies both the cost and effort to install as well as the mild inconvenience of scheduling your major consumption periods of hot water. I should add, we are not without hot water during the day. Our tank is a 75 gallon model and we often have enough hot water throughout the day for washing hands and the like.
Updated 12/22/2010 (I finally charged my old camera phone) Here's what the installation looks like. The Orange wire is 12 gage 2-wire. This is attached right next to our breaker box.