I get a lot of questions, most of them start out about geothermal—about how it works and how much it costs. It often includes a discussion about other ways to be more energy efficient. Here we are posting some of the most asked questions, as well as offering you the opportunity to ask your own.




Your Question

I have one room that is always too cold in the winter or too warm in the summer. Is there an environmental and affordable option for me?

A good choice would be a mini-split air source heat pump. We sell Mitsubishi’s Mr. Slim line, so it’s easiest for me to describe it using that example. Mr. Slim is a two-part system: one unit is mounted on the wall in the room you want to heat or cool. The other part—the heat pump—sits just outside. Mr. Slim heats and cools, is 40% more efficient than your standard A/C window unit, it won the 2009 Green Product Award, and as much as 84% of the materials used in the Mr. Slim are recyclable.

How does Mr. Slim work?

Mr. Slim is most commonly known as a split-ductless design, which simply means the indoor unit, which is self contained and doesn’t require ductwork, is separated from the outdoor unit and is connected by two refrigerant lines. During the air-conditioning process the indoor unit collects heat from inside the room while the outdoor unit rejects the heat to the outside. In the heating mode the process is reversed. The outdoor unit collects heat from the outside air and distributes the heat as warm air inside the house.

What are the installation considerations for mounting the Mr. Slim indoor and outdoor units?

The indoor unit is typically installed high on the wall. An exterior wall allows for easy connections between the indoor and outdoor units. The indoor unit is suspended on a wall bracket that is first mounted and secured to the wall. The indoor unit is mounted horizontally and must be level. For the best air circulation the unit should be mounted at least seven feet high or six inches below an eight-foot ceiling.

The outdoor unit should be mounted as close to the indoor unit as conveniently possible in order to maximize efficiency The outdoor unit may be placed close to the wall and should be above the anticipated snow level.

Some useful Mr. Slim benefits:

  • No ductwork is required: You will not have to tear up walls or add expensive ductwork to basement remodels.
  • Versatility: You can condition spaces that were previously not possible with a ducted system, Both at the home or office, Mr. Slim is flexible enough to work in almost any room environment
  • Will not take up a window.
  • Effective zone cooling and heating: True zoning means that you can tailor individual rooms to your personal comfort tastes.

I currently heat my house using a traditional forced air system, what could be done to bring down the operating cost and to reduce my carbon footprint?

A Geothermal Heat Pump system would be a good choice. It requires no oil, wood, propane, or pellets, just a power grid connection. Plus, geothermal gives you year round comfort, a warm house in the winter and a cool house in the summer without a noisy air conditioning outdoor unit.

What is Geothermal and how does it work?

A geothermal heat pump is a central heating and cooling system that takes advantage of an ambient ground temperature of 47 degrees all year long. During the summer it pulls the heat out of your home and puts it into the ground. In the winter months the system extracts heat from the 47 degree ground.The heat pump through its vapor compression cycle raises the temperature of the heat extracted from the ground to a point where it can be used to warm your home.

Well then, what is a heat pump?

A ground source heat pump is a device that transfers heat from one place to another place. In the winter months the heat pump transfers heat from the ground into the home and in the summer, from the home into the ground. The heat pump relies on a process known as vapor-compression refrigeration. It is basically the same technology that makes your refrigerator work.

What’s the difference between an incandescent light bulb and a CFL?

Incandescent light bulbs work by heating a tungsten filament, or wire, until it glows. This is what produces the light you see. Unfortunately, 90% of the energy used to generate that light is wasted as heat, making incandescent bulbs a very inefficient way to light your home. CFLs, on the other hand, create a chemical reaction among gasses located inside the glass tube, causing phosphors to illuminate.

How much energy and cost can I actually save using CFLs?

A CFL uses about 75% less energy than a traditional incandescent bulb and may last at least 6 times longer. An Energy Star qualified CFL saves about $6 a year in electricity costs and can save more than $40 over its lifetime.

How much does a geothermal system cost?

I get this question a lot and unfortunately there is not a generic answer. There are many factors that can change the pricing dramatically. How old is your home? What is the size of your home and property? How well insulated is your home? What type of heating system do you have in your home? Installation on a house under construction is less expensive than retrofitting an existing structure. There are two methods of installing the piping into the ground: vertically or horizontally. Your soil type and property size, will determine type of ground loop. Horizontal loops are generally laid in a trench 5 to 8 feet deep and then reburied. For a vertical loop system, holes are about 20 feet apart with the depth determined by the heating or cooling load of your home. Long, hairpin-shaped loops of pipe are then inserted into these holes. The number of holes drilled, like the amount of horizontal looping necessary, are factors that depend on the size of the house to be heated and cooled, as well as the specific geology around the house. Each case is individual and evaluated on its own merits. Current federal tax incentives for geothermal installations do help bring down the cost and payback time.

What are the federal tax incentives for a geothermal system?

EnergyStar.gov is a good place to track energy credits and incentives. The website announced that as of January 30, 2013, the 30% federal tax credit for geothermal has been extended:

  • Tax Credit: 30% of cost with no upper limit
  • Expires: December 31, 2016
  • Details: Existing homes & new construction qualify. Both principal residences and second homes qualify. Rentals do not qualify.

The site also offers a nice thumbnail description of Geothermal Heat Pumps: Geothermal heat pumps are similar to ordinary heat pumps, but use the ground instead of outside air to provide heating, air conditioning and, in most cases, hot water. Because they use the earth’s natural heat, they are among the most efficient and comfortable heating and cooling technologies currently available.