We all take hot water for granted. We turn a knob, wait a few seconds (hopefully very few) and it's there. No one wants to give it up because cold showers are not fun. But can we use less energy to get the same amount of hot water? Definitely.

I've got water heaters on the brain because earlier this week I submitted NRDC's comments to DOE's residential water heater and direct heater rulemaking, currently in its preliminary stages. This rulemaking is one of the big ones; possibly saving consumers as much as $40 billion, but it is still early in the process. How we heat our water could change drastically in the next few years, as this area has great potential for efficiency advances.

Water heaters generally are pretty boring. You've got a burner to heat the water and a tank to store it in until you want it. Hopefully you have a good deal of insulation to keep the heat from leaking out. But things are changing. Tank-less water heaters have entered the fray and advanced technologies are just over the horizon for the old stand-bys.

Like in lighting, where the industry is focused on getting to LEDs, the water heater industry knows what the next generation of more efficient products look like and how they will work. But how do we make it cost effective and how do we do it quickly? How do we transform an industry? This rulemaking will have a lot to do with how soon we can get to where we want to go.

The Water Heater of the Future

The water heater of the future will use a lot less energy to give you a hot shower. For tank water heaters that use gas, an Energy Factor (EF) above 0.77 requires "condensing" technology. Energy Star requires 0.80 while efficient traditional designs get 0.64 to 0.67. The difference is that instead of heating the water with a gas burner and then sending the exhaust up the chimney vent, the gases are actually re-routed so that they continue to transfer heat to the water. Eventually, the water vapor in the exhaust condenses and goes out a drain. The same technology is used in boilers and furnaces.

On the electric tank side, the next wave is heat pump water heaters. These work just like the heat pumps that folks use to cool their homes in that they take heat from one place and "pump" it to where you want it to go. For your home, you usually pump heat in from outside in the winter, and out in the summer. In the case of a water heater, the heat pump removes heat from the room it is installed in and "pumps" it into the water in the tank. A heat pump water heater would have an EF of at least 1.7. Energy Star criteria is set at 2.0 while traditional electric water heaters come in somewhere slightly below 1.0.

You could go out and buy one of these types of water heaters now, but it will cost you. This is where we have the vicious cycle of market transformation. The prices are high, but they could be lower if the manufacturers could produce them in larger volumes. But the manufacturers can't produce them in larger volumes until people buy more of them.

There are also concerns about reliability. But small scale production doesn't benefit from the quality control that large scale production can provide. We also don't know how the average consumer will react to them, but we will never know until they become affordable. No easy answers.

The tiny decisions that DOE makes in this rule will have an impact on when and how these advanced technologies become more common. If the Department does all that it can to make sure that these technologies are required where and when they are cost effective, then maybe the "water heater of the future" will be in your price range the next time you're in the market.