Authored by Douglas Mefford in Energy, Environment
Published on 04-09-2009
When a lot of the elements that comprise our homes were developed, energy was cheap and the economy was in a constant increase. One example especially is the big tank water heater for keeping a flow of hot water available. Now that the economy has driven fuel and energy prices ever upward, these often energy wasteful units must be rethought and redesigned or replaced with a new technology.
Essentially, the old tanks held a large supply of water and heated it to the selected temperature so it would be ready at a moment’s notice. Despite insulation, the heat would slowly leach off into the air and whenever even a small amount of hot water was taken out, it would be replaced by cold water, which would lower the tank’s temperature. This would then require the heating element to come on and reheat the water to get it back to the selected standby temperature. You can expect to use a fair amount of energy, whether electrical or gas, even if you have actually used no water.
To offset some of the wasted resources of the old-style water heater, the tankless water heater has been developed. This unit is installed directly on a cold water line close to the output source, be it sink or shower. Then when the hot water spigot is turned on the unit heats the water directly in the pipe for delivery. It has been referred to as “hot water on demand”. It does eliminate the extra energy costs associated with the old-style holding tank water heaters that have to be constantly running in order to maintain temperature.
There are some difficulties that must be taken into consideration. A tankless water heater will provide only two to five gallons per minute on average, with the gas powered tankless water heaters being a bit faster than the electrically powered ones. While this may be adequate for a single output area, utilizing multiple faucets or water using appliances at once may require the installation of a second tankless water heater in another area. There is also the issue of some water loss as the unit brings the incoming water up to a usable temperature.
While specific details will vary from month to month and across multiple situations, the Environmental Protection Agency’s analysis and comparison between old-style gas and electric tank water heaters compared to the tankless variety water heaters shows a regular savings in overall energy cost. While a tank hot water heater usually lasts for ten to thirteen years, the average life of a tankless water heater averages twenty years.
It may take twice as much money to install a tankless heater over an old tank water heater. The average energy savings per month covered a range between as little as a 9% savings between an electric tankless over an electric tank water heater to the gas powered tankless water heater averaged as much as a 48% savings over the same electrically operated tank heater.
Since energy costs vary so much and fluctuate constantly, it will be necessary to investigate the actual energy costs between electricity and natural gas in your locality before deciding which route to go. One thing you can be assured of is that in the long run, replacing your old tank water heater with a tankless unit will save you money and hopefully be a bit more friendly to the environment.