Natural Gas Water Heater
Product Overview

Natural gas water heaters offer two distinct choices in style (storage tank and tankless) and three choices for venting (conventional, direct vent, power vent). Additionally, you may be able to combine your water heating with home heating.

Storage Tank Water Heaters
A storage tank water heater is the most common type of water heater in Canada. It consists of a gas burner and a steel cylinder storage tank with capacities ranging from 30 to 100 gallons.

How storage tank water heaters work:

Cold water is drawn into the bottom of the tank where it is quickly heated by a gas burner. Hot water rises to the top of the tank. As the hot water is used, it is replaced at the bottom with cold water. 

A thermostat controls the heat of the water both when it is leaving the tank to your taps and when it is on “stand by”, waiting in the tank to be used. The more efficient a water heater has the less heat is lost when the unit is on “stand by”.

Tankless Water Heater (Demand or Instantaneous Water Heaters)
A tankless water heater has no tank and stores no hot water. When hot water is needed, the water is heated on demand. When the hot water tap is turned on it triggers a flow switch that sends cold water into the unit at the same time the burner is activated. The water is rapidly heated to the desired temperature. This continues for as long as the hot water tap remains in the ‘on’ position. When the tap is turned ‘off’ the system shuts down resulting in substantial energy savings over units that have hot water stored in the tank on ‘stand-by’.

A tankless water heater can save space and offer flexibility being able to be installed close to the point of use.

Combination Water and Space Heating Systems
You can have one natural gas heating unit that heats water and provides heat to your home. This is called a combination system. For home heating, the unit circulates heated water into a 'fan coil' in a conventional room radiator or tubes hidden in your floor to heat surrounding air. For hot water usage, the unit heats the water inside the coil and distributes it through separate piping to bathrooms, the kitchen and laundry room. A storage tank or tankless water heater is suitable for the combination system.

Water Heating Venting 101

A natural gas water heater requires air for combustion and igniting. The air required can either come from outside or from the home itself. There are three types of venting for natural gas water heaters, each offering benefits depending on your installation limitations and requirements:

Direct Vent
A direct vent does not require a chimney, it vents directly out the wall. A direct-vent water heater uses air from outside the home for combustion and vents directly out the wall.

This style of venting is most often convenient when:

• replacing an electric water heater and a chimney is not available

• you require that your water heater be placed beside an exterior wall

• you do not have an electrical source close to the water heater to power the vent

Power Vent
A power vent is much like a direct vent other than it uses an electrically powered vent for assistance. This style of venting is used when:

• replacing an electric water heater and you do not have ready access to a chimney

• the water heater is to be placed near an exterior wall

• you have access to a dedicated electrical receptacle within 6 feet of the unit

Conventional Vent
A conventional vent is required on most standard natural gas water heaters. Conventional vents can be either type B, double-wall metal vents or a tile-lined brick chimney. The conventional vent can be shared with most standard mid-efficiency furnaces or boilers. This type of vent draws the air it needs from inside your home. In airtight homes it is important that there is an adequate air supply from outside. If you have had a high-efficiency furnace installed a conventional vent system may require a chimney liner to be added.