Frequently Asked Questions

Note 1: Any information provided in this document should be considered as an approximation and may vary depending on individual circumstances. All information should be supported with an assessment from a registered contractor or installer.

Note 2: Measurements are provided in imperial and metric due to the tendency of the industry to use both systems.

1) What are my options for installing a ground source heat pump?
2) How big of a heat pump do I need?
3) How much electricity does it take to operate a heat pump?
4) What are the costs associated with these systems?
5) Are there any rebates available from the government for the installation of an EES?
6) What is the life span of:

• a heat pump?
• an earth loop?

7) How much space does it take?
8) Can I heat my domestic hot water also?
9) Can I use an existing water well for an open loop, aquifer system?
10) What water quality do I need to install an open loop, aquifer system?
11) How much water flow do I need to use an open loop, aquifer system?
12) What are the benefits of a vertical vs. horizontal boreholes in closed loop systems?
13) How deep of a borehole do I need for closed loop, vertical systems?
14) Is the fluid used in a closed loop potentially environmentally harmful?
15) How do I know which contractor to hire?
16) How do I ensure I am getting a quality system?

5) Are there any rebates available from the government for the installation of an EES?

The Federal EnerGuide for Houses Program offers $3500, which is the largest rebate available, for participants of the EnerGuide Program who install the system within the allotted 18 months following the initial assessment. Currently, the provincial EnerGuide Program does not fund such installations.

Note : As of January 1, 2008 , the federal government’s EcoEnergy Retrofit programme subsidies will only be available to residential customers who have a certified installation done (see above for certification info).  In addition, many provincial governments, utility programs, and municipal governments require part of all of the CGC Quality Program together with their own program requirements.

6) What is the life span of:

a heat pump?

18 to 25 years

an earth loop?

50-75 years, but is expected to last over 100 years if CSA 3408 piping is used.

7) How much space does it take?

closed loop, vertical

The pipes run straight down below the surface in a localized area spaced 3-4 m (9-12 ft) apart.

closed loop, horizontal

A horizontal loop takes the most ground area. Trenches are dug about 3-4 m (9-12 ft) apart and run for about 165m/ton underground at depths at least as deep as 2 m (6 ft) and take up space equivalent to no less than 93m 2 (1000ft 2 ) per ton

closed loop, surface water

An ocean loop would require a pipe running to the ocean and back.

open loop, aquifer

For an open loop, an existing water well can be used if the flow is sufficient. The water must be re-inserted into the aquifer through an injection well in the same aquifer. 

A consideration for any installation is the space needed for the large equipment to access the location (i.e. drillers, backhoe, trencher, etc). Also, a sufficient buffer must remain between other underground installations such as septic tanks, swimming pools, gas lines, water mains, sewers, telephone lines, or electrical lines.

8) Can I heat my domestic hot water also?

The heat generated by the heat pump can be captured and used to supplement the heating needs by 50-65% for domestic hot water with a Hot Water Generator. An electric 235 litre tank with 2 elements is recommended. If an alternative hot water tank is currently in use such as a gas, propane, oil, or electric with one element, a second tank for preheating is required.

9) Can I use an existing water well for an open loop, aquifer system?

An existing water well can be used; however, the water must be re-inserted into the aquifer somehow, either through an injection well. An injection well is generally deeper than the source well since an aquifer will uptake water at 70% of the rate that it produces it.

10) What water quality do I need to install an open loop, aquifer system?

In Nova Scotia , the groundwater quality has been found to be widely functional. Generally, if the water is regularly fit for human consumption, then it will be fine for geothermal heat pumps. For water of lesser quality, check with your heat pump manufacturer.

11) How much water flow do I need to use an open loop, aquifer system?

23-46 L/min (6-12 gal/min) is ideal. If an existing well is used, this is in addition to the domestic demands which are generally 15-30 L/min (4- 8 gal/min)

12) What are the benefits of a vertical vs. horizontal boreholes in closed loop systems?

In theory, a vertical system is more thermally stable because the temperature is more constant at 100 ft underground as compared to 5 ft underground where the horizontal loops are laid. This is claimed to be insignificant in the Canadian context. The vertical loops are more expensive than the horizontal (see question 2a). A limiting factor in the decision can be contractor availability in your area as the vertical loops require more sophisticated machinery and skilled labour. See list of contractors.

13) How deep of a borehole do I need for closed loop, vertical systems?

The general rule is 55-67 m (180 to 220 ft) of depth per ton of heat pump capacity, which can be either in one borehole or spread over 2 boreholes.

14) Is the fluid used in a closed loop potentially environmentally harmful?

The main fluids used in a closed loop system are, denatured ethanol and methanol. The nature of the in-ground loops prevents them from leaking large quantities of fluid should leaks occur because the pressure in the pipe is hydraulic and depends on a contained circuit to maintain pressure.
Methanol released into the air has a half life of 17.8 days. It breaks down into formaldehyde or it can react with nitrogen dioxide in polluted air to form methyl nitrite. In the soil methanol biodegrades as there are several types of bacteria that digest it. In water, methanol biodegenerates with the aid of bacteria. It does not readily accumulate in biota. In humans, the liver breaks down methanol into formaldehyde and formic acid. It is the formic acid that is responsible for the symptoms of intoxication by methanol such as incoordination, salivation, lethargy, narcosis, and death. Methanol is not permitted for use in Ontario . Denatured ethanol is simply ethyl alcohol (i.e. vodka, gin, etc) to which a small amount of a toxic substance has been added to make it unfit for consumption. The substance can be poisonous if ingested. It is flammable in the presence of sparks and releases CO 2 when it breaks down.

Whichever fluid is used, it must be mixed with water in accordance with instructions, methanol at 20% by volume or ethanol 25% by volume ratio of chemical to water.

15) How do I know which contractor to hire?

A Canadian body has been initiated in 2007 by the Canadian GeoExchange Coalition called the CGC Global Quality GeoExchange™ Program®. It will provide training and qualifications to contractors. These certifications would suggest that the contractor is well qualified. See a list of contractors in the Atlantic provinces.

All contractors should follow the standards outlined in CSA C488.

16) How do I ensure I am getting a quality system?

The Canadian GeoExchange Coalition certifies systems based on the CSA-448-02, provincial regulations and equipment standards by ISO/CSA. The consumer should also be provided with an ‘As-Is’ book and all piping and valves should be clearly labelled.

References

Agency for Toxic Substances and Disease Registry . (2001). Public Health Statement. Retrieved on Sept 11, 2007 from http://www.atsdr.cdc.gov/toxprofiles/tp96-c1.pdf

Cunning, Rick. (2007). Personal communication. Sept 11, 2007 .

Environmental Health and Safety. (2005). Materials Safety Data Sheet – Propylene Glycol. Retrieved on Sept 11, 2007 from http://www.jtbaker.com/msds/englishhtml/p6928.htm

Geo-Heat Centre. (2007). Geothermal Heat Pump Owner Information Survival Kit. Retrieved on Sept 11, 2007 from http://geoheat.oit.edu/

Marco, Stan. GeoSmart Energy Inc. CEO / CGC Certified Trainer. Personal Communication. Nov.1 2007.

NRCan. (2002). Residential Earth Energy Systems, A Buyers Guide. Retrieved on Sept 10, 2007 from http://www.canren.gc.ca/prod_serv/index.asp?CaId=163&PgId=910

Next Energy. (2007). Geothermal Solutions. Retrieved on Sept 10, 2007 from http://www.nextenergysolutions.com/index.html
US EPA, Office of Pollution Prevention and Toxics. (1994, Aug). Chemical Summary for Methanol. Retrieved on Sept 11, 2007 from http://www.epa.gov/chemfact/s_methan.txt