The tankless water heater
works by heating water as it is called fro by the user. It does
not operate in the same way as traditional hot water heaters
that require storage tank. For this reason there is no heat
loss. Heat loss is the heat energy you lose when heating water
and then storing it in a tank. This tankless water heater is
thus much more energy efficient.
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Tankless Water Heater Has Arrived
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Cold water is
taken into the unit and is heated by a heating element. The
heating unit can be electric resistance heating coils or a gas
burner requiring natural gas or propane. There are three
variables that have to be considered in sizing the unit. The
volume of water the user will require, the temperature of the
water entering the system, and the desired temperature of the
hot water to the user. Those three factors determine the type,
size and flow rate of tankless water heaters. There are two
basic types of tankless water heaters, Point of Use and Whole
House. Point of Use Tankless Water Heater 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 shower. Point of use tankless water heaters are typically
less expensive than whole house units. Whole House Tankless
Water Heater Whole house units mean that they have higher flow
rate capability and can supply more than one fixture at a time.
The number and type of units served is important. Some shower
heads can use six times more water than a bathroom sink. The
size and number of whole house tankless water heaters you
require will be determined by flow rate. Flow rate is
determined by the number and types of fixtures. You may need
more than one whole house tankless water heater for multiple
shower usage. These can be hooked up in parallel to meet higher
hot water demands. Whole house units are typically much more
expensive than point of use units. Determining Desired
Temperature Rise The difference between the the temperature of
the hot water leaving the heater and the cold water entering
the unit is called the temperature rise. If you want a shower
up to 110°F and you live in south Florida with groundwater at
72°F, then you need a 38°F temperature rise (110-72=38). A
tankless water heater is sized by rating its temperature rise
at a given GPM. So that could be rated at a 38°F Temperature
Rise at 2.0 GPM. If less water may be required, this same unit
might also provide a 65°F Temperature Rise at 1.0 GPM. The
lower the flow demanded by the unit, the more the water can be
heated.