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| Home > Products > Case Study: Geothermal |
In 1996 we built a new 1 ¾ story home with a walk-out basement in northeast Iowa. All 3,600 square feet is heated and cooled year round. The structure is fully insulated including the basement. We installed efficient windows and doors and sealed the house well to improve comfort and reduce heating and cooling requirements. The home is all electric and we bought appliances and lighting products that were energy efficient.
We installed a 4-ton geothermal heat pump that is connected to four outside extended slinky loops buried in a trench 165 feet long. The cost of installation was about $3,600 more than a high efficient propane furnace and air conditioner. Our payback to off-set additional costs of installing a geothermal system was just over 3-years based on propane prices in 1996.
Considering the high cost of propane fuel today, we have not only recovered our original investment, but have saved an additional $4,000 in operating and maintenance costs compared to a propane system over the same period.
The desuperheater unit connects our geothermal heat pump to the water heater and produces low cost hot water whenever the geothermal unit runs to heat or cool the house. The desuperheater cuts the cost of heating hot water in half.
Our electric cooperative provided us a rebate for installing a geothermal heat pump to reduce our installation costs. They also provide a winter season electric heat rate that helps keep our annual operate costs much lower than any propane system. Our geothermal heat pump also eliminated the need for a propane storage tank in the yard and noise air conditioning equipment located outside the house.
The amounts below are heating and cooling costs for our home since it was built. On the left are average costs by month and on the right are annual costs by year.
| January |
$ 44.07 |
| February |
$ 38.60 |
| March |
$ 26.65 |
| April |
$ 22.59 |
| May |
$ 12.49 |
| June |
$ 17.41 |
| July |
$ 29.46 |
| August |
$ 21.79 |
| September |
$ 6.22 |
| October |
$ 8.01 |
| November |
$ 23.54 |
| December |
$ 24.15 |
|
Average Annual Heating
and Cooling Costs |
$ 289.78 |
|
| 1996 |
$ 323.04 |
| 1997 |
$ 226.06 |
| 1998 |
$ 226.53 |
| 1999 |
$ 219.60 |
| 2000 |
$ 304.68 |
| 2001 |
$ 414.22 |
| 2002 |
$ 301.71 |
| 2003 |
$ 272.96 |
| 2004 |
$ 289.78 estimate* |
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