Looking to heat water and space with a single system?
Some homes simply need less heating. They may have excellent insulation, low air leakage and make efficient use of space. Or they may be located in an area with a milder climate.
In these types of homes, a single appliance can do double duty as a water heater and a space heater: a combination system.
This type of system usually consists of a fan coil installed with ductwork, and a small pump that circulates water from the water heater through the fan coil. Heated water can also be circulated through in-floor piping to provide floor and radiant heating.
Some combination systems use boilers in place of water heaters.
Combination systems are not currently regulated under Canada’s Energy Efficiency Regulations. However, look for a system that has been rated as a system using the new Canadian Standards Association standard CSA P.9—Test method for determining the performance of combined space and water heating systems (combos). This test method yields a “thermal performance factor” that consolidates measures for both space heating and water heating.
If the system has an energy factor (EF) rating for the water heater only, the energy performance picture is incomplete. The water heater will perform differently when it is in space heating mode.
When buying a combination system verify that your contractor or designer has the credentials to do the job properly. For example, the Heating, Refrigeration and Air Conditioning Institute of Canada (HRAI) offers a certification in combination systems
For related information, take a look at the Heating section of this Web site.
For a practical overview of water heaters, read our Water Heater Guide [PDF - 2.8 MB].