With energy-consuming equipment, such as water heaters and refrigerators, we have good data on energy consumption and can set clear standards accordingly. In some product categories—clothes washers, for example—Energy Star standards were adopted because those standards provide a high enough threshold to represent just the very top segment of the product market (less than 10%). In other product categories—e.g., refrigerators and dishwashers—we set a higher threshold than ENERGY STAR: for example, exceeding those standards by 10% or 20%. With lighting and lighting control equipment, certain generic products qualify, such as compact fluorescent lamps and occupancy/daylighting controls, while in other categories only a subset of products qualify. In some cases, products that meet the energy efficiency requirements are excluded, because of evidence of poor performance or durability. Microturbines are included here because of the potential for cogeneration (combined heat and power) that they offer.
Once we’ve considered low-emitting products and those that prevent moisture problems, we also consider green ventilation products, filters, radon mitigation equipment, and other equipment and devices that help to remove pollutants or introduce fresh air. Because ventilation equipment is standard, we only recognize products that are particularly efficient or quiet or which have other benefits, such as heat recovery.
Spruce Technologies offers a wide range of inline fans rated by Energy Star and by the Home Ventilation Institute, including the 100-cfm RB110 and the RP140. The RB110 is appropriate for continuous, whole-house and bathroom ventilation as well as duct boosting, whereas the RP140 is made specifically for radon ventilation. Both models connect to four-inch ducts. The company also offers models under the HomeAire brand.
Select an HVAC fan that is sized properly for your needs and uses efficient motors and drive systems.
For ceiling fans used in open commercial spaces look for fans that move large volumes of air.
GreenSpec lists high-volume low-speed (HVLS) fans with efficient motors that spin long blades very slowly. Once spinning, the fans use little energy to maintain momentum while circulating air very effectively.
If you’re looking for a residential ceiling fan, choose one with an electronically commutated motor (ECM).
GreenSpec lists only Energy Star-certified ceiling fans that use ECM motors—motors using electronic commutators (rather than mechanical commutators and brushes), permanent magnet rotors, and built-in inverters. ECM motors maximize efficiency as fan speed changes, with almost none of the mechanical energy loss or heat generation you find in AC motors. These fans are up to six times more efficient than AC-motor-driven fans.
For residential ventilation fans, including in-line utility fans, spot ventilators, and range hoods, look for units that move air efficiently and quietly. If they’re not efficient, they’ll waste a lot of energy. If they’re not quiet, people won’t use them, potentially leading to moisture and ventilation problems.
GreenSpec lists ventilation fans that are certified by Energy Star and the Home Ventilating Institute and have an energy efficiency, or efficacy, of 4 or greater, measured in cubic feet per minute (CFM) of air moved per watts of energy consumed (a fan moving 80 CFM of air using 10 watts would have an efficacy of 8).
GreenSpec requires a sone rating of no more than 1.0, which is about as loud as a refrigerator. Many ventilation fans have sone ratings of 3.0 or more. Because in-line fans are further down the duct, they're quieter and don't require a sone rating.
Beware of larger range hoods and other ventilators that pull 250 CFM or more. Particularly in newer, relatively airtight homes, that much air movement could cause depressurization and potential backdrafts in other appliances. Size range hoods appropriately.
Whole-house fans replace the use of air conditioners by pulling cool air into homes through open windows in the early morning and after the sun sets.
GreenSpec lists only whole-house fans that incorporate sealed dampers and insulation commensurate with attic insulation. Note that these products need to be used carefully. Windows need to be open to prevent backdrafts or moisture being pulled from basements and crawlspaces, and attic ventilation has to be sufficient to accommodate the airflow. They should not be used if chemicals have been applied nearby or where exhaust fumes can enter the home.
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