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Monkeying around with water heating controls

While watching the winter Olympics I saw the great ad for the new GE GeoSpring hybrid water heater.  If you missed the ad with the snow monkeys chilling out in the heated water it can be seen here.  The new GE hybrid water heater is called a hybrid because it is a combination of an electric water heater and an air-source heat pump.

GE describes how the unit works in the GeoSpring Hybrid water heater features:

A compressor and evaporator are integrated into the electric water heater unit and the evaporator draws in ambient heat from surrounding air using two variable speed fans. Condenser coils wrap the tank all the way to the bottom to transfer this heat into the tank and heat the water.

This innovative process creates the same amount of hot water as a traditional electric water heater, but can reduce water heating expenses up to 62% to save $320* per year. And that could have a dramatic impact on monthly utility bills for years to come!

On the link describing the water heater's ability to save energy GE states: "Cut water heating energy usage by up to 62%". It seems that they arrive at this number by comparing the Energy Factor (EF) of their hybrid heater (2.35) to that of a standard electric water heater (.88).  Energy Factor is defined by the DOE as:

The energy factor (EF) indicates a water heater's overall energy efficiency based on the amount of hot water produced per unit of fuel consumed over a typical day

I have no doubts that the hybrid water heater from GE is more efficient than a standard electrical water heater (the electric water heating energy cost calculator GE puts up on their site helps), but what about compared to heating with another water heating method which is natural gas?  To compare this you would need to compare the EF of a natural gas water heater to the GE hybrid heater while also taking into account the cost difference between what you pay for natural gas vs. electricity...which will mean you will probably have to do a conversion between therms (the units usually used to express natural gas consumption) and kWh (electric consumption).   It obviously gets a little complicated when comparing different methods of heating water!  This page from the California Energy Commission (CEC) is a great resource for comparing water heating methods.

The CEC estimates that heating with natural gas will cost users 1/3 the cost of heating with a standard electric heater...but if the GE hybrid heater is 3 times more efficient than a standard electric water heater then a natural gas heater and a hybrid water heater from GE would cost users the same amount to operate! ***this obviously depends on the rate you pay for natural gas and electricity

One of the Mapawatt team members has an electric hybrid water heater that is even more efficient than GE's; but only because his hybrid water heater is electric and solar thermal.

If you're interested in buying the new GE heater, the good news is that you are probably eligible for an energy star appliance rebate!  Using their online water heater store I determined that the GeoSpring has a list price of $1,699, but this doesn't include any installation costs.  Here's my advice if you are in the market for a water heater:

• If you definitely need a new water heater and you heat with electric, then the GeoSpring seems like a great choice.  Do some more research, install one, and tell us how it works!
• If you already have an efficient electric water heater than you will have to compare the initial purchase price (minus rebates) vs. your annual energy savings.  Yes, this requires a little more work on your part but you will be smarter afterward.
• If you heat with natural gas chances are it may be hard to justify the higher initial purchase price of the GE water heater.  Do the analysis though and don't be afraid to ask for help in the comments below if you need it!
• If you want to live off-grid then you can't use this water heater anyway (unless you had solar PV or a wind turbine and wanted to use that electricity for a water heater?).  Just install a solar thermal water heating system and take cold showers when it is raining outside :)