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Deep Energy Retrofit (DER)

From Wikipedia which actually sums it up well for the definition of a DER:

A Deep Energy Retrofit (DER) is the process of super-insulating older properties, and making the appropriate mechanical upgrades, so that energy usage for heating and cooling is reduced very significantly, usually 50% to 95%.  A Deep Energy Retrofit (DER) focuses primarily on energy conservation—seriously addressing a building’s enclosure—literally on all sides. It combines strategies of energy conservation, air sealing, moisture management, controlled ventilation, and insulation so that dramatic energy savings are achieved alongside optimal building performance. Durability, good interior air quality and energy efficiencies are attained by sound building science practices. In a DER, filling a wall cavity with effective insulation also requires careful consideration of how that wall will dry if moisture does happen to get past its skin. Using very high R-value insulation systems on the exterior of the building enclosure is often one of the hallmarks of a DER. Where exactly the dew-point will fall in (or out) of those thickened walls—and in what climate-becomes crucial. Careful detailing, flashing and air sealing of windows and other building penetrations is also key to a successful DER. Systems thinking is required for these kinds of retrofits, where highly efficient windows are “tuned” to their orientation, and mechanical systems are sized and integrated into how the walls, roof and basement are being air sealed, moisture-managed and insulated.

The performance of a Deep Energy Retrofit can be tested with building diagnostic tools such as a blower door test and and infrared cameras (don’t forget your smoke machine!). Rating systems in the U.S., such as the Home Energy Rating System (HERS),  tests residential performance on a numerical scale. Savings can be documented through an energy analysis, or simply tracking one’s energy bills and consumption.  While the cost-effectiveness of Deep Energy Retrofits is sometimes questioned,[2] the value of the method is being studied through numerous test cases [3][4][5], some of which have received support from energy utilities.[6] With the addition of energy generating abilities (such as solar panels), a Deep Energy Retrofitted house can be readily modified into a NetZero Energy building. Generally, the financials for a DER work better when another major renovation to the building enclosure becomes necessary—such as when the siding or roof needs to be replaced anyway. Usually, only Passive House standards can exceed the energy performance of a Deep Energy Retrofit. In cold climates where heating costs can be extreme, the DER method shows great promise for widespread viability.

NetZero Energy

A NetZero Energy (NZE) is a term used to describe a building which has a net energy consumption of zero annually. Some NetZero Energy buildings can be used autonomously from the energy grid supply, while others are grid-tied.  Most strategies to achieve NetZero rely on large amounts of insulation, good air sealing, a highly efficient HVAC system and a source of on site renewable energy, such as solar or wind.  The NetZero design principle is becoming more practical to adopt due to the increasing costs of traditional fossil fuels and their negative impact on the planet’s climate and ecological balance.

The NZE consumption principle is gaining considerable interest as renewable energy harvesting as a means to cut greenhouse gas emission. Traditional buildings use consume 40% of the total fossil energy in the US and European Union.