How does a heat pump water heater work?  What makes them so unique?

 

The heat pumps that most of us are familiar with heat and cool the air inside your home. In the summer they cool the air inside your home and move the heat outdoors.  In the winter they reverse the cycle and cool the outdoor air and move the heat indoors.

 

The heat pump water heater works in a similar way.  It cools the surrounding air (typically in a basement or garage) and moves the heat into the water heater instead of the outdoor air.  It doesn’t need to reverse the cycle since hot water is needed all year long.

 

The heat pump water heater is unique because moving heat from the air to the water consumes much less electrical power than heating the water directly using electric resistance elements.  The energy savings typically range from 40% to 60% and in ideal applications can be much higher.

 

The heat pump water heater is also environmentally friendly – by reducing energy consumption and eliminating the harmful emissions of gas water heaters

When do heat pump water heaters make the most sense?

 

With current energy prices, heat pump water heaters will save energy costs in most applications.  Installations that meet one or more of the following criteria will have the largest energy savings:

 

Electric resistance heaters are presently used (especially when electric rates are high). (Heat pump water heaters will always save money vs. electric resistance water heaters.) Hot water use is high. Where space cooling or ventilation needs are present. Homes with a fairly steady need for air conditioning most of the year, such as in warm climates. Where non-electric fuel (natural gas, propane, oil) rates are high or not available. In mild / cool climates when heat pumps are used for space conditioning In mild / cool climates where there is a need for moisture / humidity control In mild / cool climates where the water heater can extract heat from  large, unconditioned basement; or crawl space.

 Can I use the heat pump water heater with a gas or propane water heater?

 

No.  E-Tech heat pump water heaters are designed to work with the thermostats and resistance elements in a standard electric hot water heater.  Gas or propane heaters use different types of thermostats.  An improper connection to a gas or propane heater could also pose a safety issue.

 Can I just buy a storage tank?

 

No. The HPWH is designed to be connected to an electric resistance water heater. It uses the water heater electric resistance heaters for back up, and the tank thermostat to control the operation of the heat pump.  Besides, we don’t know of a storage tank that sells for less than a standard hot water heater.

 What kind of electric water heater do I need?

 

E-Tech residential heat pump water heaters work in conjunction with a standard electric water heater.  They use the water heater thermostat and storage tank.  They also use the upper heating element for backup operation.

 

The requirements of the electric water heater are:

Minimum 40 gallon storage. (Larger is generally better) Maximum tank element size of 4500 Watts. (Up to 6000 watts as an option.) Operate on 230/208 VAC, 1 ph, 60 Hz power. Hot and cold water connections should be ¾” pipe thread, spaced 8” apart, center to center.

 

The tank top should have a minimum diameter of 19” if installing the R106K (tank top) unit.

 Will I run out of hot water?

 

In normal usage you should not notice any difference in your supply of hot water.  Heat pump water heaters do heat water a little slower than your present water heater, but they are designed that way to gain maximum efficiency.  They can heat from 200 to 350 gallons per day, depending on the model.  Tank size is an important factor – a larger tank will help minimize hot water shortages.

 Are the 40-60% savings estimates real?

 

Yes!  E-Tech heat pump water heaters have been tested by more than 30 utilities around the as far back as 1978.  The test program results around the country were extremely good.

 

Units tested in a cold, mountainous region had annual savings of 57%.  Tests in more tropical locations had savings of more than 60%.  In most applications the savings should be between 50% and 65% compared to electric resistance water heating.

 What is COP?

 

COP stands for Coefficient of Performance.  It is the ratio of energy output to energy input.  The COP is calculated at a specific operating condition and does not take into account any value for the cooling and dehumidification provided.

 

 A typical E-Tech COP is 3.4, which means that for 3.4 kW of energy are provide to heat water for every 1 kW of electricity consumed by the heat pump.