Water Heating
- How important is it to insulate my electric water heater?
- What is the best temperature setting for my water heater?
- How do I change the temperature setting on my water heater?
- What size water heater should I have?
- Aside from adjusting the temperature, are there other easy ways I can save on water heating?
- What is an "instantaneous" or "on demand" water heater?
- What is the purpose of the pressure relief valve on a water heater?
- Should I drain my water heater, and if so, how often?
- Should I shut off my water heater if I plan to be away from home?
- I've heard that there is a system that uses a water heater to provide space heating – how does this work?
- How does a heat pump water heater work?
Q. How important is it to insulate my electric water heater?
A. It depends mainly on the location and age of the water heater. If the water heater is in a cooler area, more heat will be lost from the tank, making additional insulation more important. Newer water heaters have more built-in insulation than older ones, so you will save less by adding additional insulation. In most cases, you can easily save enough to offset the cost of the insulation, so unless your water heater has a label or sticker telling you not to add insulation, it is usually a good idea. Don't forget to insulate any exposed hot water pipes as well.
Note: insulation blankets are not recommended on gas or oil-fired water heaters.
Q. What is the best temperature setting for my water heater?
A. For an electric water heater, set the thermostat to 60°C (140°F); for a gas water heater, set it to 55°C (130°F). These are the recommended temperatures for health and safety. Bacteria can grow at lower temperatures, and above this, you run a high risk of scalding as well as wasting energy. Check the temperature at the faucet.
Q. How do I change the temperature setting on my water heater?
A. With a gas water heater, the thermostat control is a simple dial on the outside near the bottom. With an electric water heater, the thermostat controls are behind the access panels on the side of the water heater (there are usually two – one for each heating element). Be sure to turn off the power to the water heater before removing the access panels.
Q. What size water heater should I have?
A. It depends on family size and lifestyle, but for the average family of four, a 150 litre (40 US gallon, or 33 Imperial gallon) tank should be sufficient.
Q. Aside from adjusting the temperature, are there other easy ways I can save on water heating?
A. The simplest way to save is to use less hot water. Use low-flow showerheads, wash clothes in cold or warm water instead of hot, and only run full loads in your clothes washer and dishwasher.
Q. What is an "instantaneous" or "on demand" water heater?
A. An instantaneous or on-demand water heater is a small heating unit located close to the point of use, which heats the water just before it is used. These units have no storage capability, and are usually not well suited for "whole house" use, as multiple units are typically needed.
Q. What is the purpose of the pressure relief valve on a water heater?
A. The pressure relief valve is an important safety feature. It prevents a potentially dangerous pressure buildup in the water heater in the event that the thermostat malfunctions and fails to turn off the elements or burners. These valves should never be wired shut or otherwise tampered with.
Q. Should I drain my water heater, and if so, how often?
A. It is a good idea to drain water heaters once a year. Be sure to shut off the power or gas supply, as well as the incoming water to the tank, and let the water cool down before draining it. Always attach a hose and run it outside – do not attempt to drain the tank a small amount at a time, as sediment at the bottom of the tank may clog the drain valve, making it impossible to close until the tank has been fully drained and flushed. Once the tank is empty, turn the water supply back on and flush the tank until the water runs clear. Then refill the tank completely before turning the power or gas back on. For more information, see our related h.e.l.p. sheet, Extend the life of your hot water tank [PDF, 68 Kb]
Q. Should I shut off my water heater if I plan to be away from home?
A. If you go away for more than a day or two, it is a good idea to turn off the water heater. If the water heater is electric, you can shut off the circuit breaker. With a gas water heater, you can simply turn the thermostat all the way down or to the "Vacation" setting if the water heater has one (this shuts off everything but the pilot light).
Q. I've heard that there is a system that uses a water heater to provide space heating – how does this work?
A. This type of system, typically called an integrated heating and water heating system, circulates hot water from the water heater tank through a coil of piping, and a fan blows air across the heated pipes and circulates the air through ducts. This type of system is most appropriate for apartments, condominiums, small homes, or additions where the heating demand is minimal.
Q. How does a heat pump water heater work?
A. A heat pump water heater works much like a space heating heat pump – it absorbs heat from the surrounding air and uses it to heat water in the tank. Because it absorbs heat from the surrounding air, it should be located in a basement or other unheated area. During the summer, it can also help cool and dehumidify the basement.
