If your home retrofit includes installing a new distribution system (forced-air ducting and/or radiant in-floor) then the GeoExchange installation can be almost as easy as it would be with any other new home or building. As with any other install, a heat loss/cooling load calculation must be completed. Possibly the windows, doors, and insulation may be upgraded during a retrofit which will alone produce huge improvements to the energy efficiency of the house and substantially decreases the size of the GeoExchange system required.

The output temperatures of a water source GeoExchange heat pump (whether forced-air or hydronic) are lower than outputs of conventional heat sources. Instead of leaving air temperatures (front a gas-fired furnace) of 125F-140F, water source heat pumps produce 90F-120F air. Proper duct sizing is very important for maximum efficiency and quiet operation.

Hydronic heat pumps are limited to supply 120F so hot water baseboards will not work properly. Architectural radiant panels or radiant in-floor heating is the most suitable for hot water heating applications.

The GeoExchange source-side loop will require a vertical borehole field or horizontal trench. A vertical field can take up to 1200 sq feet of yard space for a standard size home (approx 2500sq ft). A horizontal loop field will most likely require use of the entire average property.

A major advantage to homeowners wanting to do a retrofit with a GeoExchange system is the recent availability of grants through sources such as NR Can. National Resources Canada provides ecoEnergy grants up to $5000 for the homeowner. Visit http://www.oee.nrcan.gc.ca for more information. More links are available under the Financial Assistance tab.