Tankless (instantaneous or on-demand) water heaters

A tankless water heater heats water as you use it. There is no storage tank and no water is heated and stored while you are out of the house or not using hot water. Gas-fired units in particular work well as long as you size the unit properly to your needs — an undersized unit in a household with high hot water demand will produce lukewarm water. If your family tends to have simultaneous showers or you want to be able to shower when the dishwasher is running, you will need a larger unit or you will need to change your practices so that you have only one hot water demand source at a time if you chose a smaller unit.

To work with a solar system, you need a "modulating" on-demand heater that can sense the incoming water temperature and adjust its performance accordingly and that can pass through solar-heated water on hot summer days without activating at all. Make sure your installer understands your plan to use your tankless heater in combination with a solar system and helps you select an appropriate unit.

These units cost in the neighbourhood of $2,000 to $3,000. They can also be rented from a growing number of companies. It is estimated that these units can reduce hot water heating bills by 30-40%.

Incentives

The ecoEnergy program offers two levels of incentives for tankless water heaters.

• EnergyStar qualified units with an efficiency factor of 0.82 or better receive $630 (with matching provincial rebate)
• EnergyStar qualified units with an efficiency factor of 0.90 or better receive $750 (with matching provincial rebate)
• If you are currently serviced by Enbridge Gas, you may also qualify for an additional $300 rebate. This rebate is only available until Sept. 11, 2009.

For more information on tankless heaters and information on the Enbridge rebate, click here.