Before you compare tankless water heater prices, you first need to determine the right size tankless model for your home. If you choose a model whose capacity is too low, you won’t have the hot water you require. If you choose a unit that is too large you will be paying a higher price than you need to.
The first factor that you need to consider in sizing a whole house water heater, is the hot water demand of your home. If you have a large household, and you use several hot water fixtures at the same time during peak usage times, you will need a more powerful tankless unit than a small household who only uses a shower and a hand basin at one time. Your plumber can assist you in determining your hot water demand in gallons per minute (gpm).
The second factor that you need to consider in determining the right size tankless model, is the average winter groundwater temperature in the area where you live. The lower the groundwater temperature, the more powerful the unit needs to be in order to raise the water temperature to your desired hot water temperature.
The capacity of a tankless water heater is always stated as the flow rate, in gallons per minute (gpm), that it can handle while instantly producing a particular temperature rise. For example, the Rinnai R75L has the capacity to handle a flow rate of 7.5 gpm (3 showers) while producing a temperature rise of 35 degrees Fahrenheit. For a temperature rise of 60 degrees it can only handle a flow rate of 5.0 gpm (2 showers). If you exceed the flow rate capacity of your model, you water will not be as hot as you would like it to be.
When marketing their tankless water heaters, many manufacturers inflate the ability of their models by only stating their warm groundwater water capacities. When you compare tankless water heater prices, you should, therefore, always compare the prices of units that have the capacity to satisfy your hot water demand at the required temperature rise for your area.
Tankless water heaters come in electric and gas models. At first glance it may appear that the electric models are cheaper, but when you compare the prices of models of the same capacity, you will find that the prices are fairly similar. You will notice that tankless gas units have much higher capacities than electric models.
When comparing prices you should consider tankless gas models manufactured by Noritz, Bosch, Rheem, Takagi, Rinnai and Paloma. The best electric tankless models to consider, are manufactured by Stiebel Eltron, Titan, Bosch, Eeemax and Seisco.
Finally, when you compare tankless water heater prices, you should also consider the installation costs. If you are replacing an electric or gas storage tank unit, you will need to upgrade your existing gas lines or electric supply. The electrical upgrades will generally be a lot cheaper than the required upgrades to gas lines and venting systems.