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Case Studies
Residential Case Study -- 2,000 Square foot Colonial
This 2,000 sq. foot Energy Crafted Home* in Bow, NH is equipped with a 4-ton "Classic" heat pump from Climate Master. Water for the forced air system is drawn (and returned) from its standing column well. The home qualifies for the "Heat Smart" program run by PSNH and receives electricity at a lower rate for the well pump, heat pump, and hot water.
Actual costs to heat, cool, and provide hot water for the year
ending September 1999 (family of four) was $584, (3.8 kWh/sq foot).
*The Energy Crafted Home program requires that a new home be
built with high R-Value windows, extra insulation in the walls
and attic, etc. The Heat Smart Program requires an "electro-technology" heating
system such as a high performance heat pump.
Residential Case Study #2 - Other "Heat Pump" Homes in New England
Actual metered data from Public Service of New Hampshire (PSNH)1 and Bangor Hydro (BH)2 are as listed below for a mix of various heat pump manufacturers. All of the New Hampshire data is from PSNH's "Energy Crafted Home" program. Maine's results are from a 1994/1995 BH's demonstration program with a mix of house insulation and construction, including retrofits of existing homes.
We have averaged the two sets of data and show a result of: Per Year Per Square Foot of Conditioned Space
Public Service of NH: 3.7 kWh (Energy Crafted Homes)
Bangor Hydro: 4.9 kWh (Standard Construction)
As both areas have electric rates favorable for geothermal heat pumps, typically $0.076 per kWh, the average costs are $0.28 and $0.37 per square foot per year, in New Hampshire and northern Maine, respectively.
For a 2,400 sq ft house the annual heating, cooling and domestic water heating averages:
Public Service of NH: $672 per year
Bangor Hydro: $888 per year
1 PSNH - Twenty-three homes have been monitored for
more than a year, approximately twelve more homes are being monitored
and additional data is due in several months. The range of electrical
energy used is from 2.2 to 5.9 kWh/sq ft/year.
2 Bangor - Seven homes have been monitored for more
than one year. The range of electrical energy used is from 3.4
to 8.5 kWh/sq ft/year.
Considering the effect of degree-days:| Degree-Days (typical per NOAA) | |
| Concord, NH 7,360 | 0.50 watts/square foot/Deg.-Day for Energy Crafted Home |
| Bangor, ME 8,220 | 0.60 watts/square foot/Deg.-Day For Standard
Construction/Retrofit |
|
NOMINALIZED ELECTRIC ENERGY USED by
CONSTRUCTION TYPE & GeoExchange
|
|
Knowing the construction of the home and the average electric rate in your area you can make an estimate of annual heating, cooling and domestic hot water costs. Simply multiply these above factors (F) by the average electric rate (R), by the local Degree Days (DD) and by the conditioned square feet (SF) in the house. From that simple calculation: F x R x DD x SF, 1,000 = average annual cost, you can make a reasonable estimate of averaged annual costs for a potential heat pump customer - keep in mind there is quite a spread on these factors and the results of that simple multiplication will be a fair average.
Of the 23 heat pumps at Public Service of New Hampshire earth coupling configurations are:
| Standing Column Wells | 21 |
| Pump & Overflow | 1 |
| Pond Loop | 1 |
| Vertical Closed Loop | 0 |
|
BREAK DOWN of EARTH COUPLING NEW HAMPSHIRE
Monitored Sites
|
|
In most cases the standing column wells are the same wells also used for domestic purposes, greatly reducing first costs for the home owner.
Of the 7 GeoExchange systems at Bangor earth coupling configurations are:
| Standing Column Wells | 6 |
| Pump & Overflow | 1 |
| Pond Loop | 0 |
| Vertical Closed Loop | 0 |
|
BREAK DOWN of EARTH COUPLING MAINE
Monitored Sites
|
|
Both PSNH and Bangor Hydro have programs where the heat pumps are electrically monitored separately. We are requesting similar information from other utilities in New England and near-by New York.
