The Honglso home was constructed by Pietch Builders in 2006 in Lakeville, Minnesota. The 4200 square foot, two story home was built using the following specs
The homeowners hired a home energy consultant to perform an energy analysis of the home. The consultant estimated the annual load to heat and cool the home.
Annual Load (MMBtu/year)
This estimate is translated into dollars in the following table. Dakota Electric is the service provider for this home, and offers an off peak program for ground source heat pumps and electric water heating. The off peak program offers a discounted rate of $0.039/kWh.
SB Mechanical and Geothermal, Inc. installed a geothermal system using 700 feet of horizontal slinky loop along the side and back yards. The following equipment was utilized for the geothermal system:
When designing this home, Pietsch Builders estimated the costs for both a geothermal system and using their typical heating contractor for a conventional natural gas forced air furnace at 92% efficiency, with a 13 SEER air conditioning unit. The following table lists the costs for installing each. The cost does include installation of duct work and venting.
|Radiant Floor in Basement and Bath||$1,741||$10,100|
|Upgrade Electric Service Required||$950||No Upgrade|
Cost Difference = $8,871
While the geothermal option installation is $8,781 more than the natural gas option, the increased costs are reduced with the following incentives.
All the incentives listed above reduce the geothermal installation by $4700, to a total cost of $31,218. This is $4,081 more than then natural gas option.
The Hongslo’s have provided their cost for the first two years they have been in their home. Dakota Electric meters the usage of the heat pump and water heater separately from the general electric usage as they are on the off peak program..
|Period||Annual Cost||Average Cost/Month|
Using the estimated cost of a conventional system, the Hongslo’s are saving roughly $1000 each year. With the incentives, the return on investment is 4-5 years.