Saturday, May 3, 2014

How to heat large custom homes with geothermal system

How to heat large custom homes with geothermal systems

A question I receive from people when we are designing their new custom home is how to heat it efficiently, especially when there is no access to natural gas.

When you don’t have access to natural gas then you have three options;

1. Propane heating. Extremely effective at heating, but high in cost when heating homes and water. Propane is not as efficient as natural gas when used to heat homes or water and the cost of propane is significantly higher than the cost of natural gas.

2. Geothermal heating. Geothermal heating runs on electricity and requires no burning of fossil fuels. The heating is accomplished by piping that is installed under the ground outside of the house. The piping is filled with liquid that absorbs the heat from the ground, the warmed liquid is then circulated into the furnace inside, passed over a rad, air is blown over the rad and then circulated throughout the home. Water can be warmed with the same lines by passing them through a holding tank full of water that can be then circulated through the floor for radiant heating.

3. Propane furnace with an air to air heat pump. The propane furnace was explained in number 1, when it is paired with an air to air heat pump then you have a much more efficient heating combination. An air to air heat pump works pretty close to how a geothermal heat pump works, the difference is that it takes the heat out of the air instead of the heat out of the ground. The air to air heat pump runs on electricity and not fossil foils. Since heat pumps use the outside air to warm your home there will be times when the air outside becomes too cold to extract enough warm out of it to make the heat required for your home. At that point the propane furnace takes over and supplies the needed heat until such time as the temperature goes up enough for the heat pump to start making heat again.

When you are building a large custom home out of the three options the most expensive one to have installed is the geothermal heating unit. The difference is that the monthly cost to heating your home with geothermal is significantly lower than the other two options. Geothermal heating is a long term pay back and with rising energy costs it could make a bigger difference in the near future.

For most of these three options in larger homes today we are installing two of them. That means that we are installing two geothermal units for a large custom home. The reason is because when you have an extremely large home you require such a large volume of air to be moved around that one furnace just isn’t able to handle it.

One of the most popular trends today in heating custom homes is installing dual geothermal heating units; one that does in-floor in the basement or the 1st floor and one that does the heating of the air for the rest of the house. This gives you a nice even heating, allowing your two heating sources to work together and not be overtaxed in the cold and windy winters.

When heating with geothermal your general contractor most take the time to work with the mechanical contractors and preplan out the placement of the extensive network of in-ground loops that are required to feed the furnaces and then also the placements of the heating units themselves. Geothermal units are larger units then a conventional natural gas furnace and will require more space in a mechanical room, when there is two of them sometimes you will require two mechanical rooms or one oversized room.

When you are planning your new custom home think about geothermal heating, it will be the best investment that you could ever make in your new custom home.

Rob Abbott
Operations Manager
Village Builders Inc.

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