I have hard water - is that a problem?

Minerals have less time to settle out of the water column and build up inside the heat exchanger, because tankless water heaters do not store hot water. Another advantage is that the flow of water through the heat exchanger flushes the residue each time hot water is used. Nonetheless water softener can be used with a tankless water heater, and is recommended if you have hard water problems in your home.

Which size should my tankless water heater have?

You need a model that can deliver the volume of hot water you feel comfortable with. The best method to chose the right size of your water heater is to know how many showers each model can run simultaneously. Some models can run either one or two showers at a time.And don't forget - a tankless water heater can deliver endless hot water, shower after shower.

How can tankless water heaters heat water instantly?

When you open the faucet of your shower, the flow of the still cold water triggers the heater to turn on. Then the powerful gas burners or electrical elements will turn on, rapidly heating the water as it passes through the vessel. The water is heated instantly, and the time it takes to obtain hot water mainly depends on the distance the hot water has to travel from the water heater to your shower. The burners or elements shut down as soon as you turn off the faucet. You only have to pay for the energy that you used to heat the water for taking this shower.

Bosch 2400E Tankless Water Heater

The Bosch 2400E liquid propane and natural gas tankless water heaters are very reliable whole house models backed by the best warranty and one of the bests brands today. If you want a reliable, powerful tankless water heater that can heat 2 showers simultaneously, look no further. Here a summary:

Horizontal or vertical venting possible
Max 175,000 BTU
12 Year Warranty
Electronic Ignition
Internal combustion air (1 exhaust hose)
3 inch stainless steel exhaust hose required

Bosch 1600H Hydro Power Tankless Water Heater

The Bosch 1600H Hydro power tankless water heaters burn either natural gas or propane (make sure to order the right one). They provide enough power to run one shower. This unit is able to activate the gas valve by simply using water. As an indoor device it requires a 3 inch stainless steel exhaust hose.
Max 117,000 BTU
12 Year Warranty
Internal combustion air

Rheem Outdoor 74X Tankless Water heater

This is one of the most powerful residential outdoor tankless heaters. Again, being an outdoor unit, there are less problems with the installation because there are fewer venting requirements than for indoor models.
Outdoor Installation
Max 199,900
10 Year Warranty
Built in freeze protection to -30 degrees

Rheem 53XP Outdoor Tankless Water Heater

The Rheem 53XP is an outdoor tankless water heater for smaller applications. Outdoor units are easy to install because they don't have the venting requirements of indoor models.
Outdoor Installation
10 Year Warranty
Max 145,000 BTU
Built In Freeze Protection - 30 degrees