QUESTION: I have a question with regards to geothermal heating.
With the price of electricity and natural gas doing nothing but increasing, I am seriously considering installing geothermal heating. At present, I run a natural gas forced-air furnace that heats my Winnipeg home of about 1,500 square feet.
Next summer, my wife and I will begin landscaping the backyard and I figured why not kill two birds with one stone and get the plumbing in the ground for the heating system. My question is: How deep do I have to go with my piping and how many feet of pipe does an average geothermal system require?
-- George Anthonisen, e-mail
ANSWER: Geothermal heating and cooling systems are getting much attention these days, especially with the growing desire by homeowners and various levels of government to reduce energy consumption in our homes. The answer to your question is completely dependent on several factors in the installation of a geothermal heating/cooling system in your home.
I will describe some of these and other general issues and benefits of this type of system.
Geothermal heating and cooling is a very energy-efficient system that relies on the consistent temperature of the earth, deep below the surface, to provide both winter heat and summer cooling using a heat pump. Without getting into the complicated scientific principles that make this possible, the benefit of this system is significantly reduced HVAC costs for homeowners. The drawback of this system is that many metres of underground piping must be installed, making initial installation costs quite high. Once the system is in place, the lower cost of operation will more than compensate for this factor, but it will take several years to recoup the initial investment. For this reason, I commend you on your progressive attitude in this initiative and for seeking advice prior to commencement of any work.
Many of the early geothermal HVAC systems installed in our area were in rural locations, for a variety of reasons. The main consideration in several of these areas was poor access to natural gas supplies. Natural gas was, historically, a less costly energy source for heating our homes, especially with the advent of high-efficiency furnaces. Electric heating was often accomplished in these areas with electric baseboards, limiting air movement in homes due to the lack of ducting and fans associated with forced air. Humidity issues are more common with this type of heating supply, and electrical energy costs are higher than with comparable gas furnaces. Because of this, many of the current local companies that pioneered geothermal systems were based in rural communities.
The first and most important fact to consider in replacing your existing forced-air heating system with a geothermal one is the size and location of your home and the lot it sits on. To effectively and efficiently install a system of this type, sufficient land must be available to allow for proper heat transfer through the piping from the earth. Although your home is an average size, you may require an above-average-size lot to accomplish this. If you are located in an area where the lots are small and homes closely constructed, you may have to drill far too deep into the soil to get the proper surface area of piping necessary. The alternative is to install many more, shorter and shallower sections of piping, which may take up too large an area under your yard to be practical.
Other factors include restrictions caused by underground services like hydro, water, sewer and natural gas that may prohibit installation of underground piping. Underground water and soil quality may also limit the practicality of this type of system in an urban setting. Check with your local planning office for more information.
You have the right idea in planning for possible upgrades of this type prior to landscaping improvements around your home, but installation of underground piping for this purpose is not something that should be done by amateurs. Requirements are very specific and strict controls are in place to prevent environmental damage from coolant leakage due to improper installation. This type of work should only be done by a licensed HVAC contractor well-versed and trained in geothermal heating systems.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and president of the Canadian Association of Home & Property Inspectors-Manitoba (www.cahpi.mb.ca). Questions can be emailed or sent to: Ask The Inspector, P.O. Box 69021, #110-2025 Corydon Ave., Winnipeg, MB. R3P 2G9. Ari can be reached at (204) 291-5358 or check out his website at www.trainedeye.ca.