On the less glamourous side of green kitchen & bath design, there are the behind-the-scenes considerations of how it all works. Like the magic of hot water.

There has been plenty of debate about going with a tankless hot water heater – that is, one that heats the water as it’s used, not sitting in a big tank being heated even when it’s not being used.

Rinnai has a line of tankless water heaters that can be mounted on the interior or exterior of the home, and take up far less space than a conventional hot water heater tank.

From the Rinnai site: 25% of every household energy dollar is spent producing domestic hot water. Other very useful info on their site under the Tankless 101 link

One caveat: Rinnai only makes LP and natural gas water heaters. Why no electric? Their answer:

Does Rinnai make electric tankless units?

No. There are electric tankless units available, but they have two distinct problems:

First, the cost of electricity is, on average, significantly higher than LP or natural gas. The operating cost of electric tankless units tend to be much higher.

Second, electric tankless water heaters can only produce a relatively small amount of hot water. This is because they require a large amount of electrical current to produce a significant amount of hot water. For example, in order to have the same capacity as our smallest unit you would need to provide about 120 amps of power to an electric tankless unit. This represents well over half the amperage capacity of a typical home and 5 times the amperage of a typical central air conditioning system.