Zero Net Energy, ZNE, is a very simple idea. It means the energy a building produces is the same as, or greater than, the energy it uses. For a modern home that means using minimal energy as well as using solar or other renewable sources which generate excess energy during low use times that offset the energy used during high demand times (i.e., net metering). It’s a practice that is good for the consumer, often minimizing utility bills or eliminating them completely, and good for the power grid since it enables the push towards a 24/7 100% clean grid. And in some states, it may be the law, such as in California, which passed their ZNE Action Plan in 2020.
What Are The Important Factors For A ZNE House?
Step one starts before the foundation even goes on the ground. A Zero Net Energy house is designed from the start to use fewer resources to build, use technology to its fullest advantage and utilize the weather and land where it is built. This means that designs for a ZNE house can vary wildly from place to place, a house designed to withstand the hot and humid southern US is going to have very different energy demands than a house in Chicago. ZNE houses often have shared elements across the globe, however, like windows placed to maximize natural light and efficient space utilization to keep footprints down without sacrificing comfort.
Another big element to ZNE design is a willingness to step away from traditional norms. Instead of large bay windows that let in lots of light and heat, a clerestory with reflective shelves will maximize light during the evening but prevent the harsh light during the morning. Instead of using traditional timber construction, having a concrete wall on a southern exposure can take a long time to heat up during the day, keeping the house cool, and release that heat during the evening to help keep you warm at night. Methods and design techniques are constantly evolving too, so the world of Net Zero is constantly changing.
Once the design is hammered out, it’s up to the builders to make sure the best practices are put in place during construction. This includes making sure the house is as airtight as possible, to make the insulation work as well as it can, and using modern techniques and materials to maximize design elements. Using 2×6 walls that are 2ft on center, for instance, doubles the amount of high-value insulation over a traditional 2×4 16inch on center framing. It also includes being current on the processes involved, like knowing which way low energy glass needs to face and what the acceptable tolerances for roofing insulation are.
Efficient Lighting and Appliances
Water heaters, furnaces, air conditioners, and lighting use electricity. By implementing new technology and adhering to standards like Energy Star, a ZNE house will only use a small fraction of energy compared to an older house with older appliances. LED lighting, tankless water heaters, and tier 3 washers and dryers are all components of a high-efficiency home.
Smart Home Products
As the smart home industry expands, the products have a direct impact on helping to achieve ZNE homes. The best investment you can make is in smart thermostats. These thermostats reduce energy use in a home by pre-cooling, pre-heating, reducing/increase temperature when you are not home, managing the temperature when you are sleeping, and much more.
All of these activities can drastically reduce your energy use since the HVAC is one of the largest energy appliances in any home. Furthermore, almost all power utilities provide rebates when you purchase a smart thermostat. The rebates can go up to $100 off. Make sure to check your local utility website for details.
Other must-have smart home products include sensors to activate/deactivate lights as you come in and out of rooms, automated outdoor lights, and more. Any of these things, while small overall towards energy consumption reduction (but still helpful), do provide convenience day-to-day.
Solar or other Renewable Energy Sources
The last step, when the design is worked out and the house is as efficient as possible, is to use solar and/or other renewable energy sources to produce the power the home will need throughout the year.
Oftentimes, ZNE homes need far fewer panels than traditional homes which keeps costs down and maximizes the design potential of the system. This is because zero net energy buildings overall require much less energy and thus less solar to power it.
Net Zero Energy Solutions In Your Current Home: Action Plan
So that’s great for new construction, but what if you already have a house and want to work towards a Zero Net Energy lifestyle? While you may not be able to go as extreme as a new home, there are a lot of ways you can work towards drastically lowering your energy usage, lowering the cost of the system you use to generate more.
Replace Old Lights and Appliances With High-Efficiency Ones
This is probably the easiest step. Incandescent lights use five times the power of an LED light to produce the same amount of light. A fridge from 2009 could be using 600 Wh of electricity per year, whereas a new one only uses 450kWh. For reference that means you’d need 2 solar panels to power the old fridge, where you only need one to power the new one.
Do Your Best To Seal Your House
Old houses especially are prone to gaps around windows and doors, and spaces behind trim that have no insulation at all. You may even have an old roof with no insulation. These are all places where you are throwing energy away in the form of needing more heat or more cooling to sustain a livable temperature.
Change Your Lifestyle
It doesn’t take much, but turning off lights, using natural light when you can, and turning your thermostat down in winter and up in the summer can all make big differences in the amount of energy your home consumes.
Invest In Solar
Solar is the most accessible green energy solution, and usually the cheapest. With government rebates, state incentives and the ever-decreasing price per watt it’s easier than ever to invest in solar.
What Are The Incentives For Achieving ZNE?
The most obvious one is money. A ZNE home is much cheaper in the long run than a traditional home. Combining a very low utility cost with high-efficiency products that are less prone to failure means that over 10 years a net-zero home will more than pay for the marginal extra cost during construction in savings. In addition, the government and some states will offer extra benefits.
U.S. Taxpayer Credit
The Federal Income Tax Credit for Energy Efficiency is one of the largest rebates when choosing solar and other renewables for your home, where you can get 26% of the cost back as taxes.
17 states offer net metering, where extra power generated from solar panels is sold back to the grid. The less energy a home uses, the more power it can sell back to the grid, and in some cases where ZNE and lifestyle permit a house can become Net Positive, meaning the residents actually make money off of their solar power over time.
Tax Breaks and Other Incentives
At this time the laws are changing very quickly from location to location, so if you want to go the ZNE route it’s best to check with your local government for specific incentives. However, as of 2019 17 states have passed legislation that offers large tax breaks for builders who practice net-zero construction. New York, Los Angeles, and Phoenix go even further by creating special opportunity zones that are only for high-efficiency buildings.
The rebates and incentives can get incredibly specific too, so it pays to do research. In California, for instance, there is a specific credit for things like waste to heat power technologies and energy storage systems.
Are Any States Pushing For ZNE Laws?
Many of them are, in fact!
California and Massachusetts lead the way with mandates to achieve green standards going into effect in 2020. New Jersey, Missouri, Connecticut, Colorado, and South Dakota are also working hard to cap greenhouse emissions and decrease their reliance on fossil fuels, in which high-efficiency construction will play a very large part.
California Zero Net Energy Homes by 2020: ZNE Action Plan
California is the first major state to force ZNE homes after plans were set in motion in 2007. All new construction in California must have solar panels, and the homes must be ZNE by 2020.
California has been working closely with various stakeholders, e.g., California Public Utilities Commission (CPUC), California Energy Commission (CEC), and business around the area, to spearhead ZNE in the state. They were successful.
At TheEnergyFix, our energy experts are keeping tabs on California’s ZNE action plan, framework, how it works pans out, how that impacts the wholesale energy markets, consumer markets, and much more. Stay tuned!
- Maryland passed legislation requiring 14.5% of energy to come from solar
- Missouri’s Prop C requires the states largest utilities to generate or purchase 15% of their energy from renewable sources
- New Jersey pledged to be 50% renewable by 2030
- New York, in addition to working towards 100% renewable energy, specifically states working towards a net-zero economy by 2050 and a carbon-free electricity grid in 2040
- Texas exceeded its requirement to have 10,000 MW generated from solar by 2024