There are two basic types of tankless water heaters, Point of Use and Whole House. The type you select is based upon your intended use. And your intended use will have even more to do with the cost of these units.  A good supplier of hot water heating units is American Water Heater Company.

A point of use water heater can be mounted under the kitchen sink. It creates 170 degree F hot water instantly and I love the fact that I can get a cup of tea anytime I want (like now as I’m writing this). The point of use tankless water heater is relatively small and will usually fit inside a sink cabinet or in a closet. They are typically dedicated use heaters meaning the unit serves one sink / faucet or one shower, etc.

Point of use tankless water heaters are less expensive than whole house units and cost around a few hundred dollars for the unit (without installation).

Instant Heat tankless water heaters can supply you with hot water almost instantaneously! Depending on where your water heater is located in your home, the hot water may take a while to get to the sink, shower or bathtub. Sometimes it may seem you’re waiting for an eternity! If only there was a product that delivered hot water on demand. Well now there is!

In Instant Flow Water Heater heats the water as it flows through the unit. The electric heater provides heat to the tubes within the unit. These tubes are filled with water and as the water flows through, it becomes heated. This provides you with hot water in an instant.

The water heater is compact and installs under your sink. The water connection is cut in between the supply line and the sink connection. This works out great in garages or tool sheds where you wouldn’t normally have hot water. Image how nice it would be to have hot water to wash you hands out there!

Once the water lines are connected, the device just needs to be plugged into a 125 volt outlet.

When the water faucet is turned on and water begins to flow, the flow switch in the unit turns the electric elements on. This heats the water as it flows through. The outcome is instantaneous hot water.

In order to power the heater, you’ll need to install a ground fault circuit interrupter outlet.  Remember, this is only a single-area water heater. Don’t confuse this with a whole house tankless water heater. This is designed to heat the water at one sink in your home. If you need more, go with the tankless unit. 

Under current North American conditions, the most cost effective configuration from an operating viewpoint is usually to use a central tankless water heater for most of the house, and install a point of use tankless water heater at any distant faucets or bathrooms. However, this may vary according to how much electricity, gas and water costs in the area, the layout of the house, and how much hot water is used. Only electric tankless water heaters were available at first and they are still used for almost all point of use heaters, but natural gas and propane heaters are now common.

When consumers are considering a whole house gas tankless unit, they are advised to look at how the unit functions when raising the water temperature by about 42 °C (75–77 °F). Thus, if they live in a cold weather climate, they are advised to look at the unit’s capacity with 3-10 °C (38–50 °F) inlet water temperatures, and find a size that produces approximately 15 litres/minute (4 gpm) even in winter if they have a typical-sized house and desire what is called a 2-appliance heater. This same unit may produce 25-30 litres/minute (6.3–6.9 gpm) in summer with higher inlet temperatures, but there is greater interest in year round production and usability.