Constant Hot Water Is a Good Luxury   Leave a comment

Last week we got a new water heater, and all-in-all that should be a very good thing for our comfort, our wallet, and our carbon footprint.

When we moved into this house, we found that we had to keep resetting the water heater (electric) every day or two, because it would short out and we’d stop getting hot water. Luckily the home inspector had figured out the problem and showed me the (temporary) solution. We figured that we would give it a couple of months just in case constant use would make the problem go away after it had sat unused for 2 years. That was not the case. Then at the beginning of winter I started doing a survey of energy vampires around the house and discovered that the water heater was probably being a ridiculous energy hog. I tested the temperature of the water at the kitchen sink and found that it was over 150 degrees F! That confirmed the palpable fear of scalding that I had felt nearly every time I used the hot water in that sink. So I started adjusting the temperature setting down and checking it every couple of days. There was no change. I got down to the “vacation” setting and still measured the temperature at the sink as 150 degrees. At least that explained why the thing kept shorting out: it was essentially a fully open circuit. We figured that soon it would go kaput and we’d replace it. Until the plumber pointed it out, the thought that it was a fire hazard hadn’t occurred to us.

When we finally got a plumber out to the house for the kitchen faucet problem, he was also able to do the water heater replacement. I had done no research on water heaters, though, and all of a sudden I had to decide on replacing the water heater in a couple of hours time. I wanted tankless, he said that wasn’t possible. I said OK, then I panicked and called him back asking for tankless. He checked with the supplier at the warehouse and told me that wasn’t possible, they don’t make electric tankless water heaters. I didn’t believe him so I looked online. Well apparently he was correct. There are plenty of options for point-of-use electric tankless water heaters, but not for whole-house electric water heaters. When I looked further on webpages advertising whole-house electric tankless water heaters, all I found were point-of-use electric tankless water heaters. As well as I can piece together, whole-house electric tankless water heaters were inefficient and extremely expensive so manufacturers stopped making them. Since our entire neighborhood is electric-only houses, we’re stuck with a tank water heater. I’m very disappointed.

On the bright side, though, we should save soooo much energy with this new water heater:

  1. It’s a working water heater, not a fully open electric circuit, so it will only draw as much electricity as it actually needs.
  2. It’s a working water heater with temperature controls. Instead of using all that extra energy to heat the water to 150 degrees, we’ll be heating the water to only 120 degrees (as measured at the kitchen sink/dishwasher; slightly higher at the water heater to account for temperature loss in the piping).
  3. It’s sized to code. For whatever reason, previous homeowners decided to install a 75 gallon water heater. I knew it looked large, but I didn’t realize just how large. Code dictates 50 gallons for our size house. An oversized water heater just means extra energy needed to heat/keep heated that much more water. The codes take into account how much hot water will typically be used by house size, and honestly if you need more hot water than that it’s probably past time to consider using less hot water.

There’s a reason for the 120 degree temperature setting. That’s the temperature at which water scalds skin, which is generally considered something to be avoided. So for health and safety, there is no reason to risk injury at the faucet by having the water heater set higher than that. If you have a dishwasher, though, you need really hot water, so setting the temperature to 120 degrees is a good compromise. If you don’t have a dishwasher you could probably turn your water heater down even lower to save money/energy. Many water heaters have a temperature setting dial that gives numerical values, but personally I like to do a double check at the point of use. To check the water temperature, turn on the hot water in the kitchen sink or the sink nearest to the water heater (depending on whether you have a dishwasher or are just checking for health/comfort) and let it run for a few minutes. You want to get the pipes up to the same temperature as the water to minimize energy loss through the pipe walls during transport and check the maximum water temperature at the point of use. Keep in mind that the effective hot water temperature will be lower at more distant points-of-use because of heat loss through the pipes. Eventually the temperature would probably reach the same maximum, but it might take longer than the duration of water use.

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Posted January 16, 2011 by mayakey in energy use, home

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