Energy Efficient HVAC

Saving energy with a green HVAC system could reduce your heating and cooling cost by 30%, or more. But, going green with heating and cooling is not a do it yourself project.

In both home and commercial applications, heating and cooling accounts for up to 50% of the total energy bill. If it is time to replace your air conditioning and heating units in an existing building, or if you are specifying an HVAC system for a new building, it makes good financial sense to consider energy efficient, green HVAC alternatives.

Green Alternatives

With heating and cooling accounting for up to 50% of energy bills, efficient green HVAC has become a critical requirement in both residential and commercial buildings.

Traditional HVAC Solutions

The majority of HVAC systems installed before 1992 were rated at 10 SEER (Seasonal Energy Efficiency Ratio), or less. In aging HVAC units, the SEER rating has decreased, year by year.

In an effort to increase the efficiency of HVAC systems, The Department of Energy increased the minimum SEER rating  from 10 to 13 during 2006. Most manufacturers of HVAC equipment are currently offering green high-SEER HVAC systems with ratings of 20 SEER, or greater. Replacing an older 8 SEER system with a green 20 SEER unit could reduce your heating and cooling energy bill by up  to 60%. In commercial buildings (where heating and cooling can produce 50% of the total energy bill), replacing an 8 SEER HVAC system with a 20 SEER system could reduce the total energy bill 30%.

Replacing traditional HVAC systems with similar high SEER units makes a lot of sense. However, some non-traditional HVAC alternatives may also be worth looking into.

Non-Traditional HVAC Solutions

Several non-traditional HVAC technologies are developing quickly. Depending on your HVAC requirements and appetite for innovation, they may be worth looking into. Some non-traditional HVAC approaches include:

• Automated Ducting

Commercial buildings are frequently built with a large number of individual heating and air conditioning units. During a renovation, reducing the number of HVAC units through implementing an automated ducting ducting system can reduce the HVAC energy bill substantially.

• Evaporative and Indirect Cooling

Evaporative coolers (also referred to as swamp coolers) can reduce air conditioning bills by as much as 70% in hot, dry environments. In addition, in dry climates evaporative coolers condition interior air with moisture for the benefit of occupants.

While saving energy and reducing an air conditioning bill are evaporative cooling benefits, these units do have one limitation. They lose efficiency in humid environments. Their performance is severely limited during periods of high humidity. Similar to evaporative cooling, Indirect Air Cooling utilizes an evaporative process that can reduce air conditioning bills by as much as 50%. However, unlike evaporative units), indirect air cooling does not inject humidity into the interior environment.

• Geothermal

Geothermal heat pumps provide heating, air conditioning and hot water. In the winter, they move the heat from the earth into your home or commercial building. In the summer, they pull heat out and discharge it into the ground.

Studies show that approximately 70 percent of the energy used in a geothermal heat pump system is renewable energy from the ground. The earth's constant temperature makes geothermal heat pumps one of the most efficient, comfortable, and quiet heating and cooling technologies available today. Geothermal heat pumps can reduce heating and cooling energy bills by 30% to 40% and the U.S. Environmental Protection Agency now includes them in the EnergyStar® program.

• Thermal Storage

Thermal storage is a process that stores thermal energy in reservoirs for later use. It can involve any of several technologies that store heating and cooling energy for later use. Thermal storage technologies produce cold temperatures and store that energy as ice, chilled water or other liquids. Other thermal storage technologies produce warm temperatures and store that energy as hot water.

Thermal energy collectors include solar collectors and cogeneration or combined heat and power plants.

• Radiant Heating and Cooling

Radiant heating and cooling has been a standard practice in Europe for for almost twenty years. In a radiant heating system, heated or chilled fluid is circulated through tubes in ceiling or walls. Radiant cooling systems use less than 5% of the fan energy that would be required by an equivalent air conditioning system. A radiant system separates heating, cooling and ventilation (which improves comfort and indoor air quality).

The ventilation systems and their duct work associated with a radiant heating and cooling system require only about 20% of the space required by conventional HVAC ducting. In new construction or extensive renovations, the energy saving and improved interior environment conditioning provided by a hydronic radiant system is worth considering.

Integrating Green HVAC Into
Your Green Energy Roadmap

Energy-efficient HVAC one of the several dozen green energy technologies that can reduce your energy bill and also improve your comfort, safety and the environment. While each of these technologies provides unique benefits, no single technology is a "magic bullet."

Getting the best return on your green energy investment requires integrating the most cost-effective combination of technologies possible. Consider energy efficient green HVAC as just one component of your Green Energy Roadmap.