A few weeks ago, my Lovely Wife said to me one of those things a husband hates to hear: "The water in the shower doesn't seem to be as hot as it used to be." I hadn't really noticed, but the next few times I showered, I checked, and sure enough, while the shower handle used to point to about eleven-thirty o'clock, it was now pointing to something like ten o'clock, or earlier. Maybe it was just because the weather is colder now, and so the water coming into the house is a little colder, requiring a higher mix of hot water. But She wasn't buying it.
I am cheap, so one weekend morning a few days later, I started searching the Web for how to check out what, if anything, might be wrong with our electric water heater. There wasn't as much out there as I would like, but I checked the resistance of the single element, and it seemed to be good. The thermostat was more problematic. Bob Vila's web site was said that I should be getting infinity or zero from the thermostat, and I was getting something in the middle of the scale. (I have an old-fashioned multitester.) I tried draining some of the water from the tank, but that didn't help.
The next step was to consult that other fount of free advice, my buddies. One asked me how old the water heater was.
"It's been in the house since we moved in," I said.
"How long have you lived there?" he asked.
"Get a new one. Anything you buy will be more efficient than what you have."
I looked at the labels on the side of our old water heater. It was made in 1983. If ten years is borrowed time for a water heater, then what is 25 years?
Next, I turned to my friend who works at the EPA, who is probably the only person in my circle who is more radical about saving energy than I am. (But he's not the cheapest.) He said that I couldn't beat solar hot water, and he directed me to several links at the Department of Energy. (I have since lost them.) There, I read that electric storage tanks like what I have are the worst there is for energy consumption. I read about tankless hot water systems, but they all seemed to be fueled by gas. And the more I considered solar hot water, the less sense it seemed to make for our situation.
The problem with solar water heating, I think, is that our heaviest use of hot water is for showering, which generally occurs before or just after sunrise. If we used a solar heater to pre-heat the water going into an electric storage tank, there would be no sun to pre-heat the water, and so electricity would be used to do it instead. I decided I'd rather save my limited roof space for photovoltaics.
As I started searching for water heaters, I came across a really cool tankless water heater made by Bosch, but there were problems for our situation. The thing requires 120 amperes at 240 volts, and they recommend putting the heater as close as possible to the electrical panel. In my house, the run would be something like 25 feet. Then I read a bunch of complaints on Amazon's web site: most plumbers don't know how to work on it; the computerized flow mechanisms have broken; one guy found that when his heat kicked in while he was showering, the power went out to the entire house, which had the recommended 200 ampere service; and one poor fellow got a good scalding from the hot water when the device's regulating devices failed. So, storage it would be.
I checked the Lowe's, Home Depot, and Sears web sites for what is available. Sears provided the most complete information, including the U.S. government-mandated Energy Guide information that estimates how many kilowatt-hours the appliance will consume during the year. The web site, however, did not identify the source of that number. Lowe's and Home Depot provided some sort of efficiency coefficient but no information on where that came from.
Visiting the stores was no more helpful. Sears had several units on display, but the salesman said they were old models. He provided me with a brochure that gave all the same information that was on the web site. Home Depot had no electric water heaters on display, and none of the cartons containing the electric water heaters had Energy Guide info on the outside. That bright yellow label isn't much good for consumers when it's hidden away in the box. And none of the Home Depot sales people could find the information, either, even though they were trying to be helpful. Lowe's managed to tick me off the most. They had one electric water heater on display, but a magnetic sign covered the Energy Guide label. The salesman didn't know what I was talking about when I asked him, and he didn't much seem to care. But he did at least remove the magnetic sign, which revealed the yellow sticker.
Back at home, I went to the manufacturer web sites for the Home Depot and Lowe's water heaters and eventually found the Energy Guide information. One of the companies had images of the labels but couldn't be bothered to put the kilowatt-hour rating on the web page in searchable text.
Whatever, I crunched the numbers in a spreadsheet and talked things over with my wife. We ultimately settled on a Sears Kenmore water heater; three of their models turned out to cost the least over a span of nine years.
One thing I found in doing all of this research was that even the cheapest, least efficient electric water heater was going to use only 4,822 KWH per year, while our old tank was rated for 6,042 KWH per year. At $0.0782/KHW, that's a savings of $95 per year. Friend #1 was right. The model we ultimately chose is rated for 4,622 KWH per year, which will save us $111 per year. It will pay for itself (including installation -- I'm not that cheap) in six years. I know water heaters are not as sexy as energy saving computer power supplies and the like, but the energy I will save works out to about 3.9 KWH per day, which is enough to run a desktop computer 24 hours a day. That's something, anyway.