A net zero energy building is a type of building that produces the amount of energy equivalent to the building's energy consumption through renewable resources.
In order to establish a this goal, the building should reduce the energy use by increasing energy efficiency and also produce energy. Let's look at both halves of that equation to better understand net zero energy buildings.
It is easier to offset or balance the energy use of a building when you keep that usage as low as possible in the first place. This can be seen in a variety of areas.
One of the largest is insulation and keeping heat loss to a minimum. Allowing the air inside the building to escape means that the building has to use more energy for heating (as well as for air conditioning). Thick walls and strong insulation layers are the best approach. High R-value windows means that less heat is lost through the glass, also adding to the insulation value of the building.
An added benefit to having an “air tight” building is that it will be much quieter inside, and outdoor toxins and allergens are kept out. Though with less air exchange with the outside, care needs to be taken to still have good ventilation so the air quality is high. This can include a central filtration system as part of the HVAC system.
After heating and insulation, the next significant area where energy needs can be reduced is with the lighting. LED bulbs use a tiny fraction of the electricity compared to the older incandescent (or even CFL) bulbs. For large commercial buildings, this can mean a huge savings in energy use.
Buildings can also utilize smart technology to lower power usage, by allowing temperatures and light levels to fall when there is no one around to need them. The days of leaving lights on for an entire building through the night are over.