Tankless water heaters, a familiar sight in Europe and other places, have a reputation for energy efficiency, which translates into more money in your pocket and less strain on the environment.

If you are in the market for an upgrade do a little research of your own. Most websites have helpful information to make decision making easier.

Finding the right tankless hot water heater is simple to do. The rate of flow is determined by the difference between winter ground water temperature and what’s called for at the showerhead. Another factor is the more faucets running at one time the greater the flow, which means the higher energy use. Like this:

temperature rise x flow rate = energy

Energy is measured in British thermal units (Btu) for gas water heaters and kilowatt hours (KWH) or amps for electric. Manufacturer’s websites have tables to help you with this.

Basically there are three things to consider when picking the tankless unit right for your needs:

Energy rise

Faucets running simultaneously

Hours of hot water consumed per day

Since gas is the most efficient of the two energy sources, higher numbers in these three points above would recommend gas as the best choice. Remember propane is an alternative. Lower numbers makes electric units more competitive. Gas or electric, either will gain you energy savings.

Considering the three points mentioned, it is estimated that cost savings could be anywhere from 20 to 80 percent.

Gas tankless water heaters are more expensive to install. Most warranties require installation by a technician. Outdoor models could require protection against freezing with heating and draining devices, supplied by the manufacturer. Interior models should also be safe from sub freezing temperatures. They also require special venting - some with a combined fresh air pipe and exhaust system. A unit can usually be installed in a day.