EGEE 101
Energy and the Environment

Water Heater

PrintPrint

This is another one of the big energy users (hence expenses) in your home. Generally, water heating will rank third after home heating and cooling. Many of our appliances are now much more efficient than they were 10-12 years ago. I think it might have something to do with efficiency limits mandated by the government for the area in which you live. One of the problems and advantages of the water heater is that she is a hard beast to kill and struggles on for years before the lingering death comes to a halt and your hot water heater fails.

The cheaper options are natural gas (assuming gas prices are not too high), oil, and propane, but since natural gas doesn't come to my house, I use an electric hot water heater which is more expensive.

Of course, the less hot water you use, the lower your electric and water bills will be. We use hot water for things like bathing, cleaning dishes, washing clothes, and, if you have an old house, perhaps even heating your home with a radiator.

The following are some ways to reduce your electric and water bills. Take a shower, rather than a bath. Showers use less hot water than baths. Cold showers are a bit extreme but would save both water and energy! (You could always shower with a friend to conserve.) Washing clothes in an efficient washer also helps. Aerators lower the water flow for washing hands, etc. Turn down the thermostats on your water heater. Water heaters have 2 thermostats, one each for the top and bottom element. Don't leave the tap running too long; insulate your pipes and keep the water heater in a heated part of the house rather than the deepest, darkest spot in the basement. Purchase a new water heater if you are still using an old model. These approaches will also lower your utility bills.

Water quality can also impact the cost of water heating. Hard water can add scale to the pipes and hinder the heat transfer from the element to the water.

Watch this (1:27) movie to see the effect of hard water.

Click Here for a Transcript of the Hard Water video

[Camera is zoomed in on a shower head.] Dr. Mathews: Hard water is certainly a problem in our area. And you can see pretty simply from the shower head that these hard water stains have affected it. One way I can clean it is by soaking it in a weak acid such as vinegar. [Camera shows the shower head in a glass bowl with a bottle of vinegar next to it] Dr. Mathews: By leaving this here for several hours it cleaned up the system quite nicely. Now if you have hard water whenever you are boiling water or say boiling a lot of water in a pan, kettle, or an electric kettle, [Camera zooms into the cleaned shower head.] you are going to start getting this coating in the metal. The hard water stains are going to impact the ability to do heat transfer and increase your heating costs. Now you can use vinegar to clean things like your coffee maker and things of small scale. You certainly wouldn't want to use it in a very large device like your water heater. So there your options are to replace the heating element if it is electric or one of the other things you can do is to prevent the problem from forming in the first place. And that is by taking your incoming street water, municipality water, and treating it to avoid the calcium and magnesium going into the system. There is a variety of techniques from adding salt, to magnetism, to osmosis, to all these other weird and wonderful things. But the bottom line is if you can do this you are going to have a much better heat transfer efficiencies and your hot water heating, which is a significant expense for most houses, will be considerably lowered. [Video ends]

Credit: JPM

Using Solar to Heat Water

 Picture of a pool.  The house behind the pool has solar panel on the roof.
Credit: JPM

This pool owner (one of my friends) uses active solar heat to keep her pool warm in Orlando. The solar panels on the roof warm the pool water which is pumped through the tubes when the thermostat indicates that the water from the solar heater is hotter than the pool (and the pool temperature is below the desired setting). The cage is to keep out the insects. Solar water heating (for pools or home hot water) is perhaps the most economic use of solar energy after passive solar heating.