Founder | BPI® Energy Auditor Certified Professional
Net-zero construction is all the rave now.
Every other day now, we see a big corporation announce that they will go net-zero energy by some near-future date. The politicians and central bankers seem to fit it into their speeches whenever they can, using net-zero construction as the latest buzzword.
People are starting to learn about the many ways net-zero construction can benefit them, whether they are building a new house or remodeling the one they are living in.
In this article, we’ll touch on exactly what net-zero construction is and how you may want to look into it for your next home or building as well.
So What is Net-Zero Construction Anyway?
Net-Zero construction uses advanced building science-based technologies, energy efficiency, and renewable energy to build a home or building that produces as much energy as it consumes on a yearly basis.
Not only is it environmentally friendly, but it also creates a comfortable, safe, and healthy home that saves you money over time as well compared with a traditional structure.
Net-Zero homes usually take advantage of natural lighting and heat from the sun. The houses are very well insulated.
You get state-of-the-art technologies in heating, air conditioning, and ventilation equipment as well as in lighting and water heaters to minimize energy use. Offsetting energy is generated through solar panels or other means on-site.
There’s a lot more to the concept, and if you’d like to learn some more specifics on net-zero energy building, we’ve added a lot more information below.
What Characterizes a Net-Zero Energy Building?
Net-zero construction produces a very energy-efficient building with electricity-generating capability.
A mixture of designs and technologies combine to achieve this outcome. It is not just a house with solar panels.
We live in an era when so many of the things we enjoy made possible by new technologies seem to be having adverse effects on our planet.
But these new technologies are used to reduce the harm we may be causing and make our lives better too.
Here’s a quick list of some net-zero energy components that go into the design:
- Smart design, including energy modeling
- Orientation to take advantage of sun and shade
- A tightly-sealed building structure
- A very well insulated house
- Windows and doors that use advanced energy efficiency technologies
- A carefully designed, properly installed, highly efficient heating/air conditioning system
- Energy-efficient ventilation
- Water conservation plumbing fixtures, insulated pipes
- Efficient water heating, using a heat pump or tankless heater
- Carefully designed LED lighting
- Energy-efficient appliances
- A state-of-the-art energy control system
- On-site electricity generation equipment, usually solar cells
Why Are Net-Zero Energy Buildings So Important Now?
A lot of us are concerned about climate change. As air quality decreases in areas, hurricanes increase in intensity, and the global temperature increases, there’s plenty of cause for long-term concern.
A 2018 report by the Intergovernmental Panel on Climate Change suggested the goal of net-zero greenhouse gas emissions by 2050 to avoid climate impacts from global warming, holding the temperature rise to less than 1.5°C.
Greenhouse Gas Emissions
Buildings (both residential and commercial) account for about 40% of the greenhouse gas emissions in the US.
So we’re looking at buildings as an area for possible reductions in energy use of the types that generate carbon dioxide or other greenhouse gasses. And there are ways to do it.
Net-zero homes are very efficient in their use of electricity and don’t generate much greenhouse gas in their operation.
The more widespread net-zero building becomes, the more we can reduce greenhouse gas emissions. And the cost of solar panels keeps dropping, making the goal easier to reach.
Also, much of the energy use in buildings comes from electricity. The electric power grid is stressed in places, and reducing the load helps. And the more electricity is locally produced, the fewer new transmission lines we will have to plan and build.
Many companies are making plans to make their commercial buildings net-zero.
More architects and contractors inform people who want to build or remodel homes about the possibilities of net-zero energy building. Yet relatively few people know about net-zero homes so far. Residential net-zero construction is a wide-open area.
Net-Zero Energy Homes vs. Zero Energy Homes vs. Zero-Carbon Homes
A lot of people use net-zero energy construction and zero-energy construction interchangeably, but they are slightly different.
A net-zero energy building produces an amount of energy equal to what it uses annually, but not necessarily in the same form of energy and on the same day.
Many people prefer cooking with gas, so this is allowed as long as the amount of electricity generated is enough to offset the electricity used by the house and an additional quantity equal to the energy in the gas used for cooking and perhaps water heating.
The home is usually connected to the grid and “borrows” power at night if it uses solar cells for electricity generation (the moon doesn’t produce much power).
But it generates more than it needs during the day and feeds that into the grid to “repay the loan.”
Zero-Energy Homes (ZERH)
A zero-energy home usually means an all-electric building that generates an amount of electricity equal to or greater than what it uses through energy efficiency measures along with renewable energy systems.
It does not use natural gas or oil for cooking or water heating, only electricity.
Otherwise, it uses all the technologies and designs of a net-zero house. It may use battery technologies so that it is not even connected to the grid.
Zero-Carbon Homes
A more aggressive approach to reducing greenhouse gasses is the zero-carbon home. That generates not only enough electricity to cover its annual usage but enough extra energy over its lifetime to offset the energy involved in creating all the components of the home.
Quantifying the energy that goes into building components creates a consciousness directed towards reducing the energy that goes into the home.
More recently, net-zero carbon has been dissected in the lens of the overall carbon impact of the home, divided into embodied carbon and operational carbon.
Operational carbon refers to the carbon used in running a building. It’s the sum of the carbon emitted over the lifetime of using a building.
Operational carbon comes from the normal home operations like:
- Heating
- Lighting
- Ventilation
- Air conditioning or cooling
- Power usage
Net-zero operational carbon construction entails the following:
- Designing, building, and operating a home to reduce operational energy demands
- Incorporating as much on site renewable energy sources as possible
- Calculating and disclosing in-use energy consumption and the associated carbon emissions annually
- Offsetting residential carbon emissions annually through recognized offsetting schemes
On the other hand, embodied carbon refers to a home’s carbon footprint before it’s built. It entails the greenhouse gasses generated throughout the construction process.
These emissions are associated with:
- Extraction and production of construction materials
- Transportation
- Manufacturing
- Installation
- Repair
- Maintenance
- Demolition and retrofitting
- End-of-life deconstruction
- Disposal of the materials
Achieving net-zero embodied carbon entails the following:
- Designing and constructing to minimize embodied carbon generation
- Calculating and offsetting the embodied carbon effects from material production and construction
- Disclosing the details of embodied carbon offsetting at or soon after the completion of the project
What Are Some Benefits of Net-Zero Energy Construction?
The benefits of a net-zero energy building can be many. Here is a quick list of more benefits of going net-zero:
- Financial – Net-zero homes cost very little to operate over the course of a year.
- Comfort – An outstanding feature of net-zero energy homes is their comfort. Living in one is a much more enjoyable experience than you usually find, even in high-end homes.
- Control the Air Temperatures – Better manage air conditioning throughout so that each room is within a degree or two of every other one. The construction eliminates drafts, too.
- Lower Noise – Because the house is tight, any outside noise gets muffled. You’ll be amazed at how much noise you had been just accepting as background noise that you won’t hear inside the house any longer.
- Healthy & Fresh Air – With controlled ventilation, your air stays fresh. With controlled humidity, you have a healthier environment that is less conducive to mold, bacteria, and virus growth.
- Efficient Smart Home Tech – A computer-controlled energy management system minimizes energy use. Heating or air conditioning is available only when you need it, and optionally only in the rooms you need.
Our Own First Net-Zero Construction Renovation Project – A Real Life Example
Labels aside, we also set out to complete our own net-zero affordable renovation project in Florida, with construction finishing in December of 2020.
We didn’t follow any strict certification or official process but instead used a lot of the strategies to do it as affordably as possible.
Check out our comprehensive net-zero home writeup here!
How Much Does Net-Zero Home Ownership Cost?
Net-zero houses can be of any size. They tend to be around 6.7%-8.1% more expensive to build than conventional construction of the same size. But annual operating costs are much less.
To some extent, upgrades in equipment can reduce operating expenses somewhat more, although the increased capital costs may not make financial sense.
You can find all the tax and other incentives that might be available to help offset the initial cost for your net-zero home in a database of state incentives for renewables and efficiency.
Some mortgage lenders are taking the reduced operating expenses into account in evaluating your income/expense ratio, allowing for a higher mortgage payment because less of your income will go to utility payments.
That makes the homes more affordable.
Also, studies have shown that there is a lower foreclosure rate on zero-energy homes.
Net Zero Homes’ Return On Investment (ROI)
What is your return on investment in a net-zero home?
Basically, you look at the additional purchase cost over a regular home and at the annual savings in operating the home.
There are several ways to work these figures. A simple way is to calculate payback, which is the number of years it takes for your savings to equal the additional up-front cost.
After that, you’re getting free money. Payback averages 12 years, with a range of 8 to 14 years.
A more professional approach treats the additional cost as an investment to calculate your return on investment (ROI), which is like the interest rate you get from a bank.
ROI calculations depend on variables like the increases in the cost of electricity over time and are different for different locations.
The 15-year ROI was always positive in the cities studied and ranged from 3.3% to 6.3%.
The actual ROI is probably higher since the study did not include the higher resale value, which would increase the numbers.
Conclusion
While relatively new in the world of buildings, net-zero construction is undoubtedly going to be the future.
With all the benefits that come with it, the small increased up-front cost to incorporate all these new technologies makes a lot of sense.
It benefits you financially, with low operating costs. It takes advantage of technologies and designs to give you an exceptionally comfortable living environment that is safe and healthy.
But beyond individual or single-building benefits, it reduces greenhouse gas emissions. It makes us all better stewards of the environment, which is needed to avoid big future environmental problems anyway.
It’s hard to come up with any disadvantages, except that it will make your neighbors jealous.