Tankless Water Heaters – By Orillia Home Inspector
Tankless water heaters have been in Europe and other parts of the world for quite a while and are increasingly gaining popularity in North America. For some homeowners, using a tankless water heater is a decision based on being environmentally conscious, while others are more focused on cost savings from not heating water on a continual basis. By heating water only when needed, instead of maintaining a tank full of hot water at all times, tankless water heaters can achieve greater efficiency than standard tank-type water heaters.
Most tankless water heaters are natural gas or propane fired systems with a burner, heat exchanger, venting system and controls. The burner is ignited when it detects water flow. The heat exchanger heats the water as it passes through. With a correctly sized system you will never run out of hot water. Because tankless water heaters provide hot water only when it’s needed, they can save you up to 40% on your energy bill when compared to an electric hot water storage tank. Hot water heating accounts for around 30% of our energy bills and costs the average household around $650 a year by some estimates.
Most tankless water heaters now include a mixing or tempering valve to prevent scalding. Whenever the water temperature exceeds the maximum it allows cold water to mix with the hot reducing temperature to a safe level. Tempering valves are now mandatory to be installed on any hot water tanks in some municipalities.
Tankless water heaters can also be used to heat your home. The typical home heating system will have a tankless water heater which can direct hot water through a air handling unit hooked up to your homes ductwork. This allows you to take advantage of the fast heating qualities of a tankless heater and still enjoy the comforts of air conditioning and forced air heating. Most tankless heaters set up for home heating will always give priority to supplying hot water for domestic use first by means of switching device controlled by micro switches and sensors.
Tankless water heaters have a small heat exchanger with small openings for water to pass through. Most lines, switches and valves are very small in nature which can make tankless water heaters susceptible to impurities in the water such as iron and calcium. Having a good water filter and water softener maybe required to prevent scaling or calcium build up which could cause your system to fail.
Maintenance can be very expensive on tankless water heaters. In my own experience I had bought a house with a tankless water heater which provided both hot water and heat for the home. Although the unit was only 5 years old at the time I purchased the home within a year I started having problems with the unit. Within a period of two years I had spent over $1,500.00 in repairs and when the next failure occurred I replaced the unit with a new gas furnace and rental hot water tank. The circulating pump was the last problem and the quoted repair was over $1,000.00. As you can see any potential savings for myself to continue using a tankless water system could never offset the cost of maintaining the unit. Granted the newer systems have probably come a long way in performance and reducing maintenance in the last ten years. I would always recommend investigating a tankless rental or at minimum a maintenance contract to protect yourself from expensive repairs.