FAQ's
1: Why are Geothermal Systems so expensive?
2: What are the heat exchanger loop pipes made from?
3: What are my hot water heating options?
4: I've heard that heat pumps blow cold air is that true?
5: Are log homes suitable for Geothermal?
6: What are the maintenance issues?
7: Geothermal Systems have a reputation for heating a home inexpensively, just how inexpensive are they to operate?
and
Energy Myths Dispelled
1: Why are Geothermal Systems so expensive?
Answer: The equipment costs close to the same as a quality name brand high efficiency furnace and air conditioner. The additional cost involves the installation. An open loop usually requires less capital investment than a closed loop system if the well and discharge are already existing.
A horizontal loop requires excavation equipment and pipe installation.
A vertical loop requires drilling and excavation equipment and pipe installation.
Special tools are required to fuse the plastic pipe together underground.
Special flushing and charging equipment is required to clean, air purge and freeze protect the earth loop once it is connected to the geothermal unit.
Ductwork is somewhat larger than with other furnaces because geothermal systems move about 40% more air than fossil fuel systems of similar heating capacity.
2: What are the heat exchanger loop pipes made from?
Answer: Geothermal earth loops are made from High Density Polyethylene, (HDPE) pipe. The circuits are either 3/4" or 1 1/4" diameter and headers are either 1 1/4" or 2" diameter.
The resin is PE 3408 having a cell classification, 345564 or 345434 per ASTM Standard Specification D3350, certified as being in accordance with CSA Standard B 137.1.
This is the specification referred to in CSA 445 and CSA 448 and thus is mandated by Canadian Building Codes.
CSA Certified geothermal pipe will always carry CSA Certification on the pipe itself. If it does not say CSA Certified for Geothermal Systems on the pipe, the pipe is not certified for use in a Geothermal System.
3: What are my hot water heating options?
Answer: Most systems utilize a desuperheater to transfer a small amount of excess heat in the system to a standard electric Domestic Hot Water, (DHW) tank. Annually a desuperheater can provide 50% to 60% of the hot water requirements for a family of 4 or 5.
Demand hot water heating, (a.k.a. 100% hot water heating or a triple function machine), requires that a second condenser be built into the unit for hot water heating. This feature is intended as a heat source for either partial RFH, (Radiant Floor Heating), or for pool or spa heating.
Water to water systems are dedicated water heaters, usually used to heat large RFH systems and or hot water fan coil systems. They can be reversible to provide chilled water for cooling as well. A small water to water system of one ton capacity would be an acceptable DHW heater in conjunction with a separate unit for space heating and cooling.
4: I've heard that heat pumps blow cold air is that true?
Answer: This is a complaint associated with air source heat pumps in the past that is not relevant to Geothermal Systems. Geothermal systems are designed to provide air temperatures between 95° F and 100° F. This is very close to body temperature. Most customers find this extremely comfortable as the air is neither hot or cold. Humidity levels will stay higher than with some other systems as there is no combustion taking place and the air is not dried out.
5: Are log homes suitable for Geothermal?
Answer: Most definitely, in fact it is the preferred and recommended heating method by many log home builders. The lack of combustion in a Geothermal System means that logs do not dry out as much as with a fossil fuel system.
6: What are the maintenance issues?
Answer: Like most heating equipment today, Geothermal Systems contain sophisticated electronic components. Preventative care on an annual basis will keep a ground source system in optimal condition.
Dust, clean and inspect annually all compressor contactors and fan relays as they experience the most wear and tear due to high current surges when components start up. The life expectancy is 5 to 7 years but they are relatively inexpensive components.
The air coil can become clogged requiring a cleaning.
Note: Always check and clean your filter every 3 months and inspect the air coil annually.
Occasionally the earth loop may require flushing. Sometimes when filling the system from a well, tiny CO2 bubbles are contained in the water. After some time they may collect and become noisy when the loop is pumped. A slug of air can damage a pump, snapping the impeller shaft. The loop should be checked for this condition at the annual furnace care check up.
7: Geothermal Systems have a reputation for heating a home inexpensively, just how inexpensive are they to operate?
Answer: Energy costs vary around the Province from region to region so a truly accurate energy cost picture created today may be out of date by the next month or even the next week.
The following figures are a rough guide for comparing heating sources and applications. The cost figures are as of February 2007 for Victoria, BC. The figures below are based on a home of approximately 2,000 square feet and are in Canadian dollars.
Energy/Fuel Source |
Heat value in Btu |
Units |
Cost / Unit |
Cost / |
Approx. |
Propane* |
24,197 |
Litre |
$0.885/litre |
$47.55 |
$4,755.00 |
Oil* |
36,596 |
Litre |
$1.00/litre |
$38.26 |
$3,826.00 |
Electricity* |
3,413 |
kWh |
$0.08/kW |
$23.44 |
$2,344.00 |
Natural Gas |
948,213 |
GJ |
$16.00/GJ |
$21.94 |
$2,194.00 |
Air Source Heat Pump* |
3,413 |
kWh |
$.08/kW |
$9.38 |
$938.00 |
Ground Source Heat Pump* |
3,413 |
kWh |
$.08/kW |
$4.68 |
$468.00 |
*Propane furnace @ 70% efficiency
**Oil furnace @ 60% efficiency
^Electric furnace @ 100% efficiency
^^Air source heat pump @ 2.5 COP
Energy Myths Dispelled
- Natural gas is the cheapest way to heat a home ; not true
- Electric heat is the most expensive way to heat a home; not true
- High efficiency propane is almost the same as heating with natural gas –not true
- Air source heat pumps are not as good as high efficiency gas and air conditioning –not true
In addition to the energy relationships outlined in Fig. 2., consumers should be aware that all furnaces consume electricity. Electricity is necessary for the control system to work and to operate the blower motor or pump that forces the heat around the home – this cost seems to often get forgotten when speaking with heating contractors, or fuel suppliers but electricity is a significant unseen cost when heating a home with a fossil fuel fired appliance.