A tankless water heater is a European standard which is only slowly coming across the ocean to North America.

The basic concept is that a section of water pipe is insulted and heated, such that when the hot water is turned on anywhere, the heater engages and the water, by the time it travels through the heated section of pipe, is hot when it emerges. This can result in *huge* energy savings, since a large quantity of water isn’t sitting with heat constantly being pumped into it. The downside most common cited is that it takes a short period of time before the hot water actually arrives *hot*… the volume of water that is already in the pipes when the tap is turned on will only be slightly warmed (water must travel the entire length of the pipe to arrive at the proper temperature, so water which is already part way down the pipe will only be partially heated).

However, there are several easy fixes for this problem. The simplest (and most common) is to leave the hot water running for a few seconds before using it. Turn on the shower, brush your teeth, and by the time you’re done more…