A trend in the building industry is towards Net Zero homes. The goal of a Net Zero home is to be able to provide all the energy needed for the home without using outside sources. An older term many used was “living off the grid”. When people hear that term, the mind can race to a picture of living in a tent in the middle of the Alaskan wilderness needing to forage for your food everyday. While that might sound like a fun adventure for a few days, for most of us we like the comforts we have. The good news is that Net Zero homes are designed to still give you all the modern day comforts just more energy conscience.
There are multiple components to a Net Zero home that are all designed to reduce the energy usage down to a level that can be sustained using alternative energy such as solar power. Net Zero homes look to be about 80% more efficient than a traditionally built home. To get there takes a total home approach – looking at every aspect of the build, inside and out.
Generally these homes are going to have solar panels as the main source of electrical supply. The next largest area of concentration is what is called the building envelope. This includes doors, windows, roof, and the walls. Properly and even over insulating the walls and making sure air does not leak out cracks and gaps is a key component. The goal is to maximize the energy usage of the home and not have any of it wasted by leaving the home.
The next largest area of energy usage is the HVAC and appliances. When a high efficiency HVAC system is used in parallel with a well insulated building envelope, it will greatly decrease how long it will need to run. Some homes will also incorporate a GeoThermal system that uses the ground temperature to regulate the home’s temperature. Net Zero homes are going to use energy efficient appliances throughout the home – washer, dryer, fridge, cooktop, etc. These will also be almost exclusively electric so as not to have to depend on gas.
The ventilation system of these homes is a very important element. With a sealed building envelope (also referred to as a tight house), the natural exchange of indoor and outdoor air is by nature greatly reduced or non-existent. This means that a mechanical solution needs to be added. Most homes are going to utilize either a HRV (heat recovery ventilator) or an ERV (energy recovery ventilator) depending on what part of the country you live in. The function of these units it to exchange the stale indoor air with fresh outdoor air with as minimum of an impact as possible on the temperature of the indoor air.
Other features of a Net Zero home are items such as LED lighting, low flow water fixtures, smart – programmable thermostat and even things like shingles that reduce the amount of heat absorbed through the roof.
Many would be asking right now why all homes are not being built as Net Zero homes. The answer comes down to cost. A Net Zero home is going to cost 10% to 15% higher than if you build the same home without all the focus on energy efficiency. If you are planning to say in the home for a long time, the energy savings will be more than the initial cost, but that can take between 10 to 20 years depending on where you live, size of the home and many other factors.