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Geothermal HVAC and the “Negatherm” Factor

Posted by Jay Egg

May 15, 2014 12:59:00 PM


In our first geothermal book, Geothermal HVAC, Green Heating and Cooling (McGraw-Hill Professional, 2010, p16), Brian Clark Howard and I shared a dialogue from an article wherein a commenter said that switching from a gas furnace to ground sourced heating is increasing the burning of fossil fuels, because the power plant producing the electrical power is probably burning coal, natural gas or other fossil fuels.  The argument seems valid until you understand what we call the “Negatherm Factor”.

 “Negatherm” is a term that was coined to refer to energy that would or could have been used from fossil fuel consumption, but was never used.  “Nega”, root of “negative”, meaning unused, and “Therm”  a unit of energy equal to 100,000 BTU’s, usually measures the combustion of fossil fuels for heating a home or business.  When heating from an appliance using electricity, we use “kilo-watt-hours” (kWh).  Electricity comes from many different fuel sources including hydroelectric, solar, wind, hot rock geothermal, nuclear, natural gas, coal, and diesel to name a few.  We are certainly seeing an increase in the renewable sources, the first four in particular.

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Geothermal Heating and Cooling Systems; Great for the Environment!

Posted by Jay Egg

Apr 21, 2014 12:21:00 PM

Geothermal Heating and Cooling Systems; Great for the Environment!

An earth coupled HVAC system is packed with "Earth Friendly" benefits, especially when compared with any other types of air-conditioning and heating systems. As heating and cooling systems go, a ground sourced system comes closest to the way Mother Nature would heat and cool your home if given the opportunity.


That's because with geothermal, your house becomes coupled with the Earth beneath, sharing that temperature with your environmentally friendly geothermal heat pump, similar to the way the roots of trees share nutrients with their branches and leaves. Take a look at some of the environmental benefits you can enjoy with geothermal system:

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Get Your Spring-Time Energy Savings with Geothermal Pool Heating

Posted by Jay Egg

Apr 2, 2014 12:53:00 PM

SPRING IS HERE, and the cooling season is quickly approaching. Pools that have been out of commission for the winter are likely to stay that way unless we turn the heat on.  That can get expensive.


Stop for a moment and think of how many blow dryers, computers, cooking appliances, lights and people there are in your home that add to the cooling load.  These are all a potential source of energy that can provide domestic hot water and be used to heat spas and pools. With standard air source heat pumps or air conditioners, the heat generated inside your home typically goes out the return air ductwork and ultimately is exhausted through outside air exchange.

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Affordable Green

Posted by Green Builder Staff

Oct 9, 2013 9:10:00 AM

THE ST. CROIX VALLEY HABITAT FOR HUMANITY Eco Village, River Falls, Wisc., teamed up with local and national companies to build truly affordable and really green homes for Habitat families.

Four families are about to move into their Eco Village homes in what will be an 18-home Habitat Community built on five acres. River Falls donated the land, which is near public transportation as well as pedestrian and bike paths. Eco Village will include a community center, community gardens, and walkways as well as photovoltaic solar on each home and a shared geothermal system to heat the homes. Much of the landscape will also be edible. The goal is to achieve carbon negativity and net-zero energy use.

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Geothermal Heat Pump

Posted by Tom Miller

Aug 2, 2012 1:09:00 PM

News flash: Geothermal heat exchange systems ARE NOT a source of renewable energy. And it’s OK with me.

LATELY THERE HAVE BEEN A NUMBER OF ARTICLES and blogs questioning the efficiency and energy savings of geothermal (ground source heat pump) systems. Several of these articles “exposed” the shocking fact that these systems are not renewable energy sources like wind, solar and hydroelectric.

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