Water heating systems
A water heater uses a heating source (usually a flame or electric resistance element) to raise the temperature of incoming cold water to a desired pre-set end use temperature. The water can be heated and stored in an insulated tank, ready for use when needed, or it can be instantly heated and passed through the system directly to the end use.
The purchase price and operating cost of each can vary significantly. Some types of water heaters may cost you more to buy, but will cost you less to run year over year. Choose the option that fits your lifestyle and budget. The cost to operate your water heater will depend on the type of water heater you choose, how much hot water you use, and current energy rates.
Storage water heaters
These are the most common type of natural gas water heater. Water is heated and stored in a tank so that it is available to use in the home at any time. When a storage water heater is not in use it loses heat through the shell of the tank. New natural gas storage tank water heaters have increased insulation levels to help minimize the heat loss. Conventional (standard) natural gas water heaters are normally the least expensive type of natural gas storage water heater. Conventional water heaters may share the same chimney used by the furnace or boiler. Side-vented water heaters can be vented outdoors through a wall by using a direct vent or power vent. Side-vented water heaters cost more to buy but cost a little less to operate than conventional water heaters.
Tankless water heaters
Instead of using a tank to store hot water, these heaters, also known as on-demand or instantaneous water heaters, only heat water when it is needed and avoid heat loss through the tank walls and water pipes. Tankless water heaters are more expensive to buy, but use less energy than storage natural gas water heaters, and reduce operating costs by about 30%. Natural gas tankless water heaters have electronic ignition and power-vented exhaust. They are usually installed close to where hot water is needed. Depending on your hot water use, a tankless water heater may not have enough capacity to meet your home’s needs.
Electric storage water heaters use electric heating elements that are located in the storage tank. Electric water heaters lose heat through the shell of the tank when hot water is not being used. New electric water heaters come with increased insulation levels around the shell of the tank that help reduce heat loss. Speak to a licensed electrician before installing an electric water heater for the first time to see if any adjustments are needed to your electrical service.
There are 2 types of solar water heating systems, passive and active. Active systems are more commonly used in cold climates like ours.
Active systems have solar collectors mounted on a roof or south facing wall. These collectors absorb the sun’s radiation through a heat transfer liquid. The radiation is converted into useable heat energy by pumping the heat transfer liquid through a heat exchanger, typically located in a secondary storage tank. This heat exchanger pre-heats the water entering the conventional hot water system, reducing the amount of energy needed to bring the water up to the desired temperature.
Solar water heating systems can operate year round and typically raise water temperatures by 5 to 10°C, which means you could save up to $175 a year on your energy bill.