Energy Efficient Homes
Did you know the design and construction of your home can affect its overall health, comfort and operating cost?
The key components to a healthy and comfortable home are: airtight, well-insulated buildings with limited thermal bridges, solar orientation and shading, high-performance windows, heat recovery ventilation, electric heating and induction cooking.
Expand each component section below to learn more.
Airtight, Well Insulated Buildings with Limited Thermal Bridges
Airtight and well insulated homes are quieter and maintain consistent indoor temperature more easily. Air leakage or air infiltration allows unheated air to enter your home through unwanted or unseen gaps and the air you’ve paid to heat escape. Air-tightness is the degree of air leakage or air infiltration a home has. Air-tightness eliminates unpleasant drafts in your home. The basic principles of an airtight home are installing well sealed windows and doors, minimizing penetrations in walls and ceilings, and sealing air movement at joints in framing. Replacing uncontrolled air infiltration with mechanical heat recovery ventilation allows for more fresh air in your home without losing or gaining as much heat as uncontrolled air infiltration.
Insulation provides resistance to heat flow allowing a home to better maintain desired indoor temperatures. An insulation material’s effectiveness is determined and measured by its thermal resistance, also known as R-Value. Insulating your home to achieve high R-values can reduce the home’s heating and cooling load while also allowing it to be more comfortable. It also dampens the amount of sound from outside that infiltrates a home, making the home quieter. Homes are typically only insulated once in their lifetimes, adding a high degree of insulation will pay dividends for years to come in increased comfort and lower energy costs.
In addition to increasing the insulation required, a building with a more complex form is likely to have a higher proportion of thermal bridges. Thermal bridging happens when a material (or lack thereof) within a wall’s structure that allows a faster than normal rate of heat transfer, like the 2×4 studs in a wall that sit between the insulation. In addition to the shape of your home, strategies like a layer of continuous insulation on the outside of your home can reduce thermal bridging. Source
Solar Orientation and Shading
Designing your home so that the rooms that are used most during the day face south means they will get light and heat from the sun, reducing the need for mechanical heating systems and electrical lighting, making them more pleasant and comfortable. During the summer, appropriate shading and roof overhang can reduce the amount of solar heat gain when the sun is highest in the sky.
Designing your roof for southern exposure also maximizes the energy generation capacity of any future rooftop solar.
Heating and Cooling
High Performance Windows
Windows can make up a significant portion of your building budget but do many jobs: let in natural light and views, bring in fresh breezes, eliminate drafts and insulate. Choosing high-performance windows and the number of windows is a fundamental part of your energy design. Triple pane windows reduce heat loss or gain through the window and increase the surface temperature of the inner pane, which reduces the sensation of cold drafts.
Window placement to maximize solar gain in the winter, while minimizing in the summer, is also important.
Heat/Energy Recovery and Ventilation
Although they cost a bit more [before incentives] than standard electric or gas water heaters, heat pump water heaters easily pay for themselves in annual energy cost savings.
Compared to Energy Star gas water heaters, heat pump water heaters are about five times as efficient, with 50% less carbon emissions, and have about the same annual energy costs.
Compared to electric resistance water heaters, Energy Star heat pump water heaters (HPWHs) consume about 1/3 as much energy, reducing your annual energy costs for hot water by 67%.
Compared to Energy Star propane water heaters, HPWHs are about five times as efficient, reduce annual energy costs by 75%, and reduce carbon emissions by 60%.
For more information on heat pump water heaters, click here.