Posted by: greenpinkies | July 4, 2011

Cost of Energy efficient Improvements or “Trip around the Solar System without the budget of NASA”.

Under the tab on this website called “Nitty Gritty”, you will see a basic description of the Energy Efficient Systems we wished to put into place in this house for the heating and cooling.

Note: We did our best to be accurate in reporting numbers. But, these figures may not be 100% accurate. We will update when new information comes in.

We decided to do a Hydronic heating system consisting of a partnership between solar heated water and a Rinnai tankless water heater.  The water thus heated would heat forced air for the house using a Hydronic Air Handler (donated by the Rinnai corporation), as well as under tile heating of the kitchen and bathroom floors (Uponor).  This system will also supply the domestic hot water for the house.

Here is the cost breakdown for the entire Energy Efficient makeover :

Total cost of all systems: $31,102.47

 With that, we commence our tour around our Solar System:

We begin with the roof where we have a 4’ x 10’ panel from Sun City Solar.

 This panel is a ‘closed system’  This means that pipes passing through it circulate a mixture of distilled water mixed with food grade Glycol  are a closed loop and never mix with the actual potable water for the house.  Instead, this mixture circulates through the panel with the help of a small photovoltaic solar panel connected to a pump, goes down into an 80 gallon storage tank, in the kitchen and heats the 80 gallons of potable water to 170 degrees.

This water is then circulated through the Rinnai Tankless water heater.   At this point the tankless determines and mixes the water  if necessary, until the water is 140 degrees and sends it on to the Hydronic furnace, (located in the hall closet)   The furnace operates very much like the radiator on a car in that is has many, many ‘fins’ for transferring the heat from the water to the air.   The air is then blown through ductwork into all parts of the house.

Simultaneous to this, the hot water from the Solar tank is sent to Rinnai tankless, who cools it down to 70-80 degrees and sends it though an Uponor track system of plastic tubing under the tile floors in the bathrooms and kitchen.

Also simultaneous to this, the Rinnai tankless will moderate the water to 120 degrees when domestic hot water is called for.

Kitchen Uponor before tile

Floor after tiling

Cost breakdown:

Water Heating and House Heating systems:

 Sun City Solar:  $4,120.81

Includes:  Solar hot water heating panel, lightly used ,  plus 80 gal tank

North Star Plumbing: $10,341.34*

         Includes: Rinnai gas fired, tankless, water heater:  $1,159.03

Rinnai Hydronic Furnace:  donated

Uponor underfloor heating track system: $5,225.05

Installation of whole-house plumbing, w/toilets, showers, sinks, etc.

Here is a commendation:  Rick and Ed at North Star were  instrumental in encouraging donations or wholesale from Rinnai corporation and Uponor. We believe their efforts saved us $4662.92 in the plumbing department:

*Real Cost of Energy Systems

Air Handler, Rinnai,  donated        $1,800       = savings:  $1,800

Tankless Water heater, wholesale: $1,159.03   original cost $2,317  = savings:  $1,157.97

Uponor, wholesale: $5,225.05       original cost $6,930     =savings:   $1704.95

                       Savings total (donated value):     $4,662.92


Hvac and Air Conditioning

Ozark Mountain Air: $6,131.22

Includes:  2Ton 2 stage Rheem Air conditioner: $2718

Ductwork, labor

Natural State Insulation:  (discounted)   $4255.00

Includes:  Attic blow -in, 12”   $975

Visqueen in crawlspace,  plus open cell foam under floor     $1890

3” open cell exterior wall insulation $1390

Hanke Brothers Windows: (50% off  retail) $4865

Includes: Low E, Argon filled, double pane, 2 sliding doors and 7 windows

EcoVantage Skylights (2)     $858.25

Home Energy Consultants: RESNET rating (discounted  rate) $530.85

Price of Happy Hollow,  purchased  August 2010:      $74,000

Price of Energy efficient Improvements:                     $31.102.47

Total:   $105,102.47

 Summary:  Since houses in the neighborhood of Happy Hollow appraise for $114,000-$120,000, our total is acceptable to the investment.

The current, (subject to change), HERS score with these improvements is: 52

This means that the Happy Hollow house will be consuming about 50% less energy from now on than a comparable house built in 2006

Ahhhh    but this is not the end of the story.  You see, the house was not habitable when we bought it.  Sooo….how much more money did it take?  Was it worth it?  Did we commit the unforgivable sin and overprice the house for the neighborhood?   Da Da Da Dah….Stay tuned….



  1. I installed my own domestic solar water heater system in another house, plus a wood/coal auxilary boiler. I was involved in building our present house using underfloor hydronic heating fired by a gas boiler, and a seperate solar domestic water heater. Even with that experience I got dizzy reading the description of your system. The proof of the design will be how well it keeps the house warm this winter. I wish you luck! The sun dosn’t shine at night or on overcast winter days when you will need heat the most, so you will be depending on the tankless heater at those times. From what I have read in the Ozarks Electric magazine most tankless units can supply hot water for one faucet or shower at a time. Your design is asking it to do that, plus heat the entire house. Well, let us know how it turns out in about February.

    • Hi Maurice!
      Thanks for the post. We apologize that our description of the system sounded really complicated. I think this is because we sometimes aren’t technical writers when it comes to our descriptions.
      Regarding whole house heat: We too had our concerns about a tankless water heater supplying water for domestic and whole house heat at the same time. That is why we have been working closely with the Rinnai Corporation. The unit we installed is engineered to work in concert with a Rinnai Hydronic furnace and has been designed and engineered for the purpose of whole house heating. After seeing the credentials of this particular tankless, we worried that it was way more than was needed for our “not so big house”. Actually, we also have the advantage that our house is very small, just under 1500 square feet. So, hopefully, the math is done correctly and February will be as comfortable as October.

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