Deciding to install a ground source heating & cooling system is a big financial investment, so it is important to install one that will provide the most comfort, benefits and energy savings for your home. A significant portion of high cost of ground source heating systems is installation of the underground portion, known as the loop field. Typically, installation of the loop field is about 50% of the total upfront cost. Factors such as the type of loop you choose, size of your home, amount of land you have, climate, and quality of soil will all have an effect on the installation cost of the loop field. While you will need professional help evaluating all of these factors and choosing the best system, knowing this information ahead of time will enable you to ask the right questions, and to purchase the optimal ground source heat exchane system for your home.
Factors that you need to consider before installing a ground source heating system:
Availability of Land:
The size of your land, as well as the landscaping you have done will have a great impact on the type of system that will work well for your home. While you may have a large back yard, installation of a ground source heating system requires a lot of empty space underground. Consequently, other underground utilities and sprinkler systems will affect the design of your loop.
The composition of your soil will affect heat transfer rates, and therefore will need to be examined to determine which system will work best in your particular conditions. Soil that has good heat transfer properties requires less piping to gather a certain amount of heat than soil with poor heat transfer properties. For example, sandy soil absorbs less heat and therefore requires a larger loop field. On the contrary, dense soil that contains a lot of rock and clay has the ability to hold on to heat and to transfer it well. In general, the drier the soil, the larger the loop field required.
A ground source heating system will be highly effective regardless of the climate you live in, since earth temperature underground remains constant and is not affected by air temperature fluctuations outside. However, if you live a in colder climate, you will require a more extensive underground piping field to accommodate your heating needs during the cold season. While the initial installation of a larger system will cost you more money, you will still save up to 40% on your energy bills, which typically skyrocket during the winter.
Size and insulation of you home::
The sq. footage area of your home will have a direct impact on the size of the ground source heating system that you will need to adequately heat and cool your house. Simply put, if you have a big house, you will require a bigger underground piping field. You can optimize the size of the system you need by making sure your house is properly insulated. In particular, you can save money by insulating your doors and windows, as well as walls and attic, so that cold air does not get in, requiring you to turn up the heat. It is important to install the system that is right for the size and insulation of your home. If you get one that is too big, you will be getting more heat than you need and paying more for it as well. If you get one that is too small, you will not have adequate heating and cooling for your home, and will ultimately loose comfort.
An expert ground source heating system installer will evaluate your home and its surroundings to determine which ground source piping loop will meet your home’s energy needs. There are 3 different types of loops that are most often installed for residential purposes:
Horizontal Ground Closed Loops:
If you have a large plot of land as well as the type of soil where trenches can be easily dug, a horizontal ground closed loop may be right for you. With this system, trenches are dug three to six feet below the ground, and pipes are laid out parallel to each other. This system is 400-600 feet long for each ton of heating and cooling.
Vertical Ground Closed Loops:
If you live an area with a lot of rocky soil that would be very difficult or impossible to dig through, or if you have a very limited lot of land, you have the option of installing a vertical ground closed loop. In this system, instead of digging trenches, vertical holes 150-450 feet deep will be bored through the ground. A single U-shaped pipe loop is inserted into the ground before the hole is backfilled. Each vertical pipe in the system is connected to an underground horizontal pipe that carries fluid in a closed system to and from the indoor exchange unit. This type of loop is more expensive to install, but it is also more efficient than the horizontal one, and requires less pipes.
Pond Closed Loops
If your house is located near a shallow body of water such as a pond or a lake, a pond closed loop system may be the most economical option for you. In this system, polyethylene pipes are shaped as coils so that more of them fit in a given space. Fluid circulates through these underwater pipes in the same way it does through ground pipes.