Thursday, November 17, 2011

Tankless water heaters versus Hybrid water heaters

It really seems like a total waste of energy when you consider traditional water heaters constantly heating a 40 gallons of water even when not in use, day or night. And then if two or more people shower one ends up rinsing with COLD water.

traditional tank water heater
A tank water heater should be replaced afeter 10 years. Most home owners however only replace theirs when it breaks which usually means lots of water every where which can cause other problems. So check the date of intallation on your water heater and act swiftly if approaching the end of life.

As the cost of energy rises, many are switching over to Tankless or Hybrid water heaters. Also there is a 30% federal tax credit allowance for tankless water heater.
Tankless water heaters have been around for a while and widely used in European and Asian countries. Hybrid water heaters are a new technology only available to the masses since 2008.
Here is a comparison of the two:

Tankless water heaters:
There are many foreign and domestic tankless water heater manufacturers.
how a tankless water heater works
- Tankless are generally Gas powered (Natural or Liquid Propane Gas) are the only type that can provide enough hot water, electric models require a lot of power and are not economical. Electricity; however, is needed to control the heating process, the computer that controls the valves. These can be run on a backup battery system if desired at additional cost.

- Tankless water heaters as the name implies do not store any hot water, but they heat water on demand.  The water is forced through a spiral of pipes, called a heat exchanger, and a gas heater heats the pipes which in turn heats the water that flows through the pipe.
Endless hot water since there is no tank to run of hot water. That is important if you want to take a bath and have hot water left over.

-Tankless water heaters are very energy efficient. In fact about 98% efficiency means that only 2% of the energy is wasted on and not used for heating the water that used immediately.
Rheem tankless water heater
Traditional tankless water heaters are 30% to 50% to start with. As sediments and other build up in the tank this number reduce rapidly over time.

-You always get clean water, where as bacteria, rust and sediments are common features of tank water heater as they get older.

- Tankless water heaters are available in different sizes and if sized right, multiple people can take showers at the same time and not to worry about cold showers.

 - Tankless Water Heaters need a minimum flow to operate, usually 05. Gallon per minute (GPM). That is you cannot have the faucets just trickling hot water when brushing or shaving, a bad idea anyway, wastes too much water.

- The cost of tankless water heaters vary anywhere from $300 to $2000 depending on manufacturer and size.  

How a hybrid water heater works
Hybrid Water Heater

GE and Eternal are the two name brands of Hybrid water heaters.

-Hybrids use both a small tank, usually about 2 gallons where the water is kept hot. So instead of having a 40 gallon tank like your regular water the Hybrid works similar to a tankless but has a 2 gallon tank.
The water is drawn from the small tank and the unit replenishes as it is getting used. This allows for  “trickling” hot water, for instance when brushing teeth.

-Hybrids are about 94% efficient due to the heat loss through the 2 gallon tank, but there is a small chance of sediment buildup again because of the small tank.

-Hybrid water heaters cost around $1100 to $2700 depending on the manufacturer and brands.


  1. Thanks for informing me a bit more about solar hot water heathers. I've been doing extensive research into solar water heating for my home.

    1. Solar is a great way to go. thanks for reading the blog.


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