If you've taken the steps to improve the efficiency of your current system and you continue to experience problems or if your HVAC system is old (10 -15 years) or not working, consider replacing your equipment with a high-efficiency unit that has earned the ENERGY STAR. It's a good idea to do some research on options for a new heating or cooling system before your current one breaks, so you can make an informed decision if you need to act quickly. How much energy you save will vary based on your use and climate, with colder regions saving more with ENERGY STAR heating equipment and hotter regions saving more with ENERGY STAR cooling equipment.
Furnaces are the most commonly used residential heating system in the United States. Running most often on gas but sometimes on oil, propane, or electricity, furnaces deliver their heat through a duct system. Furnaces that have earned the ENERGY STAR have higher AFUE (Annual Fuel Utilization Efficiency) ratings. AFUE is the measure of heating equipment efficiency represented as a percentage. Most furnaces that can qualify for the ENERGY STAR will be "condensing" furnaces where the transfer of heat is so thorough water or condensate is a byproduct of combustion. This condensing occurs with systems over 90% efficient. Another feature of efficient furnaces is a highly efficient blower motor (commonly an ECM, Electronically Commutated Motor, or another type of "advanced main air circulating fan"). This new blower system uses less energy than a standard 100 watt light bulb and at the same time circulates air at a lower rate of speed between cycles improving overall comfort level within your home.
A boiler heats your home by burning gas, propane, or oil to heat water or steam that circulates through radiators, baseboards, or radiant floor systems. Boilers do not use a duct system. Boilers that have earned the ENERGY STAR have higher AFUE ratings. The features that improve boiler efficiency include electronic ignition, which eliminates the need to have the pilot light burning all the time and technologies that extract more heat from the same amount of fuel.
Central Air Conditioners:
Most residential central air conditioners are called "split-systems" because they have an outdoor component with a condenser and compressor and an indoor component with an evaporator coil. It's very important to replace both of these units at the same time. Installing a new outdoor unit without replacing the indoor unit is likely to result in low efficiency and may lead to premature failure of the system. ENERGY STAR qualified central air conditioners have higher SEER (Seasonal Energy Efficiency Ratio) and EER (Energy Efficiency Ratio) ratings than today's standard models. SEER is the most commonly used measurement of efficiency for air conditioners. It measures how efficiently a cooling system will operate over an entire season. EER measures how efficiently a cooling system will operate when the outdoor temperature is at a specific level (95 degrees F). The central air conditioner also needs a blower motor, which is usually part of the furnace to blow the cool air through the duct system. The only way to ensure that your new air conditioner performs at its rated efficiency is to replace your heating system at the same time. It's especially recommended if your furnace is over 15 years old. If you purchase a new energy-efficient air conditioner but connect it to an older furnace and blower motor, your system will not perform to its rated efficiency.
Heat pumps provide both heating and cooling in one integrated system. Electric Air-Source Heat Pumps (ASHPs), often used in moderate climates, use the difference between outdoor and indoor air temperatures to cool and heat. ENERGY STAR qualified ASHPs have higher SEER and EER ratings than conventional models. They also have a higher Heating and Seasonal Performance Factor (HSPF), which measures the heating efficiency of the heat pump.
Geothermal Heat Pumps:
Geothermal Heat Pumps (GHPs) are similar to air source heat pumps but use the ground instead of outside air to provide heating, cooling, and often water heating and radiant in floor heating. Because they use the earth's natural heat, they are among the most efficient and comfortable heating and cooling technologies currently available. Although initially expensive, you can achieve significant cost savings on energy bills. GNPs are most often installed in new homes and can be retrofitted into existing homes without much modification to the existing duct system.