Beware of the tankless water heater and the believed savings in owning one. First of all, the cost to purchase and install is nearly twice that of a direct vented water heater. Most consumers have little knowledge of the maintenance that these types of water heaters require. A yearly flushing of the heat exchanger is required to remove scale build up on the inside tubes of the heat exchanger. This is a time consuming process and therefore a costly service call.
Most tankless systems come from outside North America, and have very very poor technical support. They also have poor parts networks set up in North America, which makes getting service parts difficult and time consuming. North Americans are familiar with that big old tank that sat down in the basement giving them nice hot water for many years, with virtually no maintenance. Think twice before purchasing a tankless system.