Tankless Hot Water Heater vs Tank

Regardless of your lifestyle, hot water is an essential component. The average Canadian household uses 75 litres of hot water each day, using it for a cup of coffee in the morning, or a relaxing bath on a cold winter day. Hot water accounts for 19% of the energy that a household will use. A majority of the time, it is taken for granted that when we turn the faucet, the hot water will work, but what if it doesn’t?


Rinnai tankless water heaterCurrently, there are two styles of products available to provide your house with hot water.

First, the conventional storage water heater. It’s exactly what it sounds like, and probably what you first thought of. It’s a large tank ranging from 75-300 litres, that takes in cold water, and heats it up for use throughout your house. Generally, tanks will run on natural gas, propane, or electricity. The average lifespan of a hot water tank is between 8-12 years, but will vary depending on use and other factors.

Every time you take water out of the tank, more cold water rushes in to replace what was lost, ensuring that there is always water in the tank. However, the tank will still run out of hot water if it is all used before the new cold water can be heated to the correct temperature. In order to keep the water in the tank at a constant temperature, the tank must always be working, which leads to additional costs in your electric or gas bill. A hot water tank with a thermal resistance rating of R-12 to R-25 will help reduce the energy loss from the tank.

Recently, tankless water heaters have come into style, especially in smaller homes that do not have the space to fit a large tank. The tankless units are generally wall hung, and can fit into smaller mechanical rooms, or the walls of a garage. The average tankless heater will last around 20 years, but just like the conventional hot water tank, this depends on a few different factors. The parts on a tankless unit are typically easy to replace, meaning the lifespan may be able to be extended if it can be repaired and serviced.

The tankless water heaters are also referred to as “on-demand heaters”, because water is only used when it is needed, and not stored like in a conventional hot water tank. When a hot water faucet is turned on, cold water rushes into the unit, where it is warmed by either natural gas or propane burner. This means that the tankless heaters are much more energy-efficient than conventional tanks, as they do not have to work constantly to keep any water warm. Along with the savings on your gas or electric bills, the efficiency of the unit is also eco-friendly, as it only uses natural gas when it is required.

Although there is constant hot water, the flow is limited as it can only heat up so much cold water at a time. The unit will provide enough hot water for three people to be using the system at once. For larger houses, it may be recommended to use multiple units throughout the house to maximize your hot water.