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Welcome to my website shower insider – all about water!

Here I share info about water heaters, water filters, shower heads and any water related subject out there 🙂

Things to consider when looking for a water heater…

There are a number of factors you should consider including incoming water temperature, maximum desired water flow rate, and fuel type : natural gas, propane, or electric tankless water heater. We are here to make this whole process as easy as possible for you. We will walk you through everything you need to know in order make an informed decision and buy the best for your needs.

1. Figure out your home’s required temperature rise.

Unlike a regular water heater, a tankless model’s water output gets affected by groundwater temperatures. The same tankless water heater that provides 8 gallons per minute (GPM) when installed in a warm-climate area (i.e Texas) will only be able to output around 4.5 GPM when installed in a cold-climate area (i.e New England). Simply because colder water requires the temperature to be raised 77 degrees rather than 44. With that said, use your coldest groundwater temperature to calculate the gallons per minute you’ll need.

In order to calculate the difference between your ground water temperature and your needed hot water temperature (which is typically 120°F), find your average groundwater temperature on the image map at the right, and subtract this from 120°F to get your desired temperature rise.  (Note: 120°F is hot enough for most applications.  However if hotter water is needed, a higher number can be substituted.)

For example, if you live in California, you have a ground water temperature of 57 degrees Fahrenheit. To reach an ideal hot water temperature of 120 degrees Fahrenheit, subtract 57 from 120. You have a required temperature rise of 63 degrees Fahrenheit.

average groundwater temperatures in USA

2. Choose between Gas, Electric or Propane

Tankless water heaters are becoming an increasingly popular choice among homeowners for many reasons. For many homeowners, the lack of electrical power or the availability of natural gas or propane to their home dictates what type to go with. However, The choice many other people have to make, any time a water heater needs changed, is whether to go gas or use an electric one.

We’re not going to get into the debate about which is better; – electric or gas water heater – they both clearly work, and there is no easy and simple answer to the question of which is better. Choosing the right one for your household or business depends on your individual situation, your needs and circumstances. Deciding between the two can be tricky.

For example, climate is an important factor to be considered in making the choice. The colder the water the less output you will get from the heater. Therefore, if you are living in cold weather, you’ll need a powerful one. Here are a few other things you should consider :

  • Price and Cost of Installation
  • The ready availability of a source of natural gas/propane/electrical supply
  • Environmental impact
  • The difference in cost between the two (electric and gas)in the size of water heater you need
  • Desired location to install
  • Energy costs and forecast of future price of electricity and gas in your area
  • Water usage habits / patterns
  • Personal preference


3. Calculate how much hot water (GPM) you need at any time.

Storage-type water heaters are rated by tank capacity in gallons, and by recovery time, which is the time required for the tank to reach a desired temperature when filled with cold water.

Tankless ones are rated differently. Instead of total gallon capacity, they are rated in gallons per minute, and by the maximum temperature rise possible at a given flow rate.

In order to make sure you never run out of hot water, your tankless water heater’s maximum gallons per minute should never be exceeded. If there is certain time of the day when a huge amount of water is being used, then you’ll need to evaluate the GPM for that time of day.

Add up the total amount of hot water that you may be using at at one time. For example, if you want to be able to run the shower, a dishwasher, and the clothes washer simultaneously, you would have a usage of 3.5 – 7.5 gallons per minute depending on the flow rate of your shower, dishwasher, clothes washer and fixtures.