Tankless Water Heater Pros and Cons

Tankless Water Heaters

A tankless water heater is smaller than a traditional water heater because there's no tank. The unit attaches directly to a wall near the point of use and only turns on when you use hot water somewhere in the home. You can install it indoors or outdoors, and you can get multiple tankless water heaters to provide hot water for different parts of your house. Some tankless water heaters can be mounted on the outside of the home in appropriate climates.

With on-demand water heating, you get hot water when you need it. There are no delays because the hot water supply can never run out. However, the rate of hot water production depends on the specific unit, so you may not be able to run multiple appliances at once.

Typical flow rates for a gas tankless water heater are around 5 to 10 gallons per minute, while electric tankless water heaters usually have flow rates of 2 to 5 gallons per minute. Most units can accommodate two to three people taking showers simultaneously. 

An electric tankless water heater is powered by the same electrical system powering lights and appliances throughout your home. Once hooked up to your electrical system and water pipes, the unit is always ready to heat water on demand.

Activation

When a hot water tap or line is turned on in the home, a group of temperature sensors inside the tankless water heater activates the heating element, allowing an electric current to pass through the element to heat it. This causes the temperature to rise in the chamber inside the unit. A sensor monitors the temperature of the water coming in as well as the hot water being produced to ensure that hot water is kept within a safe, comfortable range.

Water Heating

Water from the home's main plumbing system enters the unit and passes through the heat exchanger. This warms the water to a set temperature within seconds.

Water Usage

After passing through the heat exchanger, the water exits the tankless water heater through pipes connected to faucets and appliances in the home. The hot water supply continues to flow until the faucet or appliance is turned off.

Venting

With an electric tankless water heater, no venting is required because the unit doesn't use combustion to generate heat.

More Efficient

Because tankless water heaters only turn on when hot water is needed, they use less electricity or gas than a tank heater that has to maintain a full tank of water at a specific temperature 24 hours a day. This saves on energy costs and helps you maintain a more environmentally friendly home.

In general, electric tankless water heaters are slightly more efficient than gas tankless water heaters, but both are more efficient than traditional tank models. Gas prices also tend to be more volatile than electricity prices, so an electric unit may provide a more consistent month-to-month or year-over-year cost than a gas unit.

Compact, Space-Saving Design

Tankless water heaters take up less space than a traditional tank water heater. Most households with a tank water heater have a dedicated room or closet for the tank, and larger tanks that hold more hot water take up more space. Tankless units simply attach to a wall and don't require a separate room.