News & Blog


Energy Star Requirement Change

EPA is updating ENERGY STAR requirements for dishwashers and furnaces effective January 20, 2012.

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HUD Policy Update on Performance Contracting

HUD releases Notice 2011-36 to update its policy on performance contracting. Notice PIH 2011-36 replaces PIH 2009-16.

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Applying VRF? Don’t Overlook Standard 15

Variable refrigerant flow (VRF) systems have become increasingly popular as an HVAC equipment option providing high energy efficiency at reasonable initial costs with the added benefit of simultaneous heating and cooling.

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Research Blog

Envelope Efficiency to Address Ice Dams

Ice dams are caused when snow packed on a roof begins to melt, runs down, and re-freezes when it reaches the roof edge (eave). If melting and refreezing persists, a barrier of ice forms at the eave which stops any meltwater from running off the roof.

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Ductless Mini-Split Heat Pump Comfort Evaluation

Ductless mini-split heat pumps (DMSHPs) offer an alternative to traditional central heating and cooling systems (CACs). Advantages of DMSHPs include…

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Controlling Indoor Humidity in Residential Environments

Humidity is often overlooked when it comes to providing a comfortable and healthy indoor environment.

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Measured Performance of a Low Temperature Air Source Heat Pump

A study conducted by NREL measured the performance of a 4-ton low temperature heat pump (LTHP) system over a 20 month period…The results of the study show that the technology lived up to claims by the manufacturer that the system could operate down to -30°F and supply all of the heat needed for home with very minimal use of a supplemental heat source.

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Modeling Microinverters and DC Power Optimizers in PVWatts

Solar photovoltaic (PV) module-level power electronics have become increasingly popular for residential and commercial installations. These systems have several benefits over traditional central inverters, such as: Increased design flexibility, Monitoring of system performance as detailed as real time energy production of each panel, Improvement of energy capture from single panels not producing electricity rather than entire strings…

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Green Building Water Efficiency Strategies: An Analysis of LEED NC2.2 Project Data

This study analyzes project compliance paths used by a sample of projects that earned water efficiency (WE) credits under LEED for New Construction v2.2. The sample of 448 projects that earned at least one of WE credits 1, 2, and 3 indicate that credit 3 (Water Use Reduction – 90%) and credit 1 (Water Efficient landscaping – 96%) were earned much more often than credit 2 (Innovative Wastewater Technologies – 13%).

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Residential HVAC Maintenance for Energy Efficiency

Proper maintenance is essential to achieving persistent energy savings with a high-efficiency HVAC system. Commonly, issues such as improper refrigerant charge, coil fouling, and clogged filters decrease a system’s performance from its rated efficiency. However, with proper maintenance, the detrimental effects of these problems can be mitigated.

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Light Emitting Diode Coating Can Drive Down White LED Light Prices

Scientists in the US created a new light emitting diode (LED) coating from a relatively inexpensive metal organic framework (MOF) in the form of a film coating. This new alternative may be used as an alternative to existing white LED coatings, which are made of more expensive rare elements.

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