Many builders, designers, realtors, and lenders have been reluctant to jump into the zero energy home market because they lack a full understanding of the features and benefits these homes offer and they may have concerns about possible risks. Sam Rashkin, Chief Architect with the Building Technologies Office at the U.S. Department of Energy (DOE), was a primary driver of the ENERGY STAR Homes program at the Environmental Protection Agency (EPA) and then at the DOE. Now he’s promoting DOE’s Zero Energy Ready Home (ZERH) Program which is perhaps his most ambitious endeavor to date. DOE’s Zero Energy Ready Program, like other zero energy certification programs, offers a thorough package of technical features and marketing knowledge that translates to business success for builders, realtors, and developers, and comprehensive value for homebuyers. Rashkin recently released a video promoting the ZERH program and laying out a clear, comprehensive understanding of zero energy and zero energy ready homes. Here are some highlights:
Zero Energy Ready
The new ZERH program provides easily adopted standards that any builder or designer can follow for making homes zero energy ready. The ZERH program modestly increases the technical requirements of ENERGY STAR Homes and incorporates additional elements from the EPA’s WaterSense and Indoor Air Plus programs. The ZERH program guides builders and designers through every step of the process. The result is an affordable, easy to design and build home with low energy needs that can be met with on-site solar generation or third-party carbon offsets.
A Few Simple Steps for Builders and Designers
The energy code landscape has changed considerably in the last ten years. While codes typically lag behind “best practices” for insulation, air sealing, ventilation, and equipment efficiency, the most recent code cycles are narrowing the gap. Most states currently operate under the 2009 or 2012 International Energy Conservation Code (IECC). It takes only a few simple steps above those codes requirements for builders and designers to reach the zero energy ready goal. Then, just add solar collectors and you will have a zero energy home. Any builder or designer can build this kind of zero energy home.
Build the Home of the Future
There is mounting pressure for codes to require new buildings to be zero energy by 2030. Zero energy homes will be the homes of the future. Building a home to code means that its energy performance, health, and comfort will be outdated the minute it’s complete. While better than in the past, most codes still don’t rise to the level of building techniques or cost-effectiveness currently available in more advanced buildings. Nor do code-built homes provide optimum economic performance over the full life cycle of the home. A new home that lasts 80 years should not be obsolete when the next code cycle bumps up insulation levels, equipment efficiency, or other features. A zero energy ready home is ready for the future – creating a unique selling advantage for builders and realtors.
Our technical understanding of construction practices is now firmly based in building science. Most builders understand that buildings are not a collection of separate components, but, rather, a system that controls the flow of energy, air, and moisture. It’s no longer acceptable to adopt one or two ideas. Systems thinking comes with the package. Zero energy homes start with several carefully integrated upgrades, such as an advanced enclosure with more insulation, less air leakage, better windows, improved ventilation systems, etc. This systems approach leads to a better, healthier, more durable building.
Low Risks with High Benefits
Builders and designers may be aware that the advanced enclosure carries some risks. But when implemented as part of a systems approach, each risk comes with greater benefits.
Moisture can be trapped by tight construction. Higher insulation levels create colder surfaces that are slow to dry. The solution is careful water management for roofs, walls, foundations, and sites. Interior materials are chosen to protect the building from water vapor and whole-house ventilation maintains acceptable levels of indoor relative humidity. In a systems approach, careful attention is paid to the moisture risk, leading to a home that is more moisture proof, more durable, more comfortable and healthier than a code-built home.
Heating System Sizing
The advanced enclosure means low heating and cooling loads, which, in turn, leads to smaller heating and cooling systems with shorter run times and longer swing seasons. Depending on the climate, this may reduce humidity control and air mixing, especially if the system is sized too large. Oversized systems can cycle on and off too much and fail to properly regulate temperature and humidity. The solution is an optimized heating and cooling system that is properly sized and installed. The installed system is fully tested and adjusted to professional standards before occupancy, leading to superior humidity control and air mixing and even greater comfort than is often found in conventional homes.
Indoor contaminants can accumulate inside highly airtight buildings due to lower building air leakage. Contaminants exist in all buildings, but here again, the health risk becomes a benefit because it is tackled directly in three ways. First, contaminants, such as formaldehyde and volatile organic compounds (VOCs), are eliminated from interior materials as much as possible. Next, a fresh air system expels remaining contaminants and moisture and filters fresh incoming air. Finally, a high-capture filtration system removes particulates as they circulate through the heating and cooling comfort system. Instead of an indoor air quality problem, we now have a home with superior air quality, making for a healthier home in the end.
The Advantages of Zero Homes
Once risks have been transformed into benefits, it’s time to understand how zero energy homes are better homes than those built to lower standards. Raskin describes those advantages in his video and we have summarized them in our blog post How to Sell Zero Energy Homes. With these advantages in mind, wouldn’t all designers want to design and all builders want to build zero energy or zero energy ready homes? Wouldn’t realtors be proud to be selling these homes? And wouldn’t lenders prefer to lend on these homes? We are optimistic that the answer is, yes.