Reliable Hybrid Water Boiler with an excellent Cost-Efficiency Ratio

For the last several years,  the price of heating oil has been rising significantly.  Therefore, I said goodbye to my 14-year-old oil-fired water boiler and started looking for reasonable alternatives.

The design of my first inexpensive water boiler was  based on the Whirlpool's 40-gallon regular electric water heater with fused ceramic shield tank for anti-corrosion protection.  I bought it from the Lowe's just for $248.

Then I added all necessary components and connected my new water boiler to one of my heating  zones:

To reduce the cost of electricity I would recommend installing  any type of a Time-Switch for the of-pick metering.

 In 2010 I designed my  Heat Pump Furnace  to test some of my ideas:

Frosted Evaporator (when Evaporator fan was turned OFF):

Finally, in 2013 I designed my Hybrid (Electric/Heat Pump ) Water Boiler:
The design of my second and more energy efficient water boiler is  based on  GE's 50-gallon hybrid electric water heater:

Condenser coil filled with hot refrigerant heats water in tank:

 I bought it for $950.  The final cost is $250 ($400 rebate and $300 Tax credit).

You can check all possible Rebates & Incentives for your zip code here.

After installation and inspection, I received my $400 rebate check very quickly - just in two weeks!

This modern and energy efficient water heater is a real bargain. It costs less than the lowest price of a regular 50 gallon electric water heater ($950 - $400 rebate - $300 Tax credit).
Moreover, based on GE calculation: “The investment return period is less than 1.5 years with application of federal tax credit and other state and local utility rebates.“ In my case the investment return period will be about one year.

I recommend you first use a new GE unit as a regular water heater during the full warranty period  to confirm quality and reliability of your unit.

In the below setup I use the Whirlpool's 40-gallon regular electric water heater as an extra tank and as a base to mount all necessary components.  It also serves as a failover option, in case something happens to my hybrid  boiler.

A large, unconditioned basement that is also perfectly isolated from seasonal temperature extremes represents one of the key elements of my success.  My house is well insulated too.
That means I need  to use less energy to keep my house warm.

Some additional Notes:
Air-source  heat pumps take natural heat from the surrounding air. The efficiency of air-source heat pumps  on cool days is about 175% to 250%.  But "when outdoor temperatures fall below 40°F, a less-efficient panel of electric resistance coils, similar to those in your toaster, kicks in to provide indoor heating. This is why air-source heat pumps aren't always very efficient for heating in areas with cold winters." 
The only new generation of air-source heat pumps (with about 14.0 HSPF) is more efficient in a cold climate. But these heat pumps are still costly.
-The efficiency of geothermal heat pumps/ground source heat pump (GSHP)  is about 300%-600%. And according to the U.S Department of Energy: "An average geothermal heat pump system costs about $2,500 per ton of capacity. If a home requires a 3-ton unit, then it would cost about $7,500 (plus installation and drilling costs)."
The efficiency of my GE GeoSpring™ Hybrid Water Heater is 235% in Hybrid modeIn the Hybrid mode "unit will use less energy, while still providing you with a fast recovery time. If needed, the standard electric elements may activate for a faster water temperature recovery time. Once the system determines that demand has been met, it will automatically revert back to using the heat pump only." GE
- When an outside temperature is not too cold,  my boiler works in the Heat Pump (only) mode as the most energy-efficient mode for this water boiler (heater).
The heat pumps exhaust cool air in the area where it is located, therefore the water boiler (heater) should be installed in a location that would isolate/absorb cool air such as garage, basement, attic or crawlspace.

- My basement's 6"concrete slab plays the role of a heat/cold exchanger.  And when cool air ( 4°C-7°C)generated by the heat pump sinks, the slab absorbs it very efficiently. 
- During the heating seasons the ground temperature (temperature of  the  concrete slab in my basement) is very stable: about 10°C to 14°C (50°F to 57°F).  And it rises drastically (up to 20°C/68°F) when I use my  Sauna (Banya), "powered" by a wood stove.  At the same time temperature around heat pump rises up to 30°C/86°F!
- The heat pump's operating range is 7°C to 49°C (45°F to 120°F).  If ambient temperature is outside of this range, the heat pump will turn off and the boiler will use electricity to heat water until the ambient temperature returns to within the operating range.
- In spring and fall when the outside temperature is higher than my basement temperature, I will show how to use a duct fan with a differential controller to increase my system’s efficiency.  The differential controller measures the outside temperature as well as my basement temperatures and turns on the fan if the outside temperature is 3 degrees Celsius greater than the basement temperature.

You can use a FLIR  Infrared  Camera  to see how the Reflectix insulation helps to reduce heat losses.

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