Three new net-zero energy homes are being certified in Asheville this week, and you can tour them all this weekend and next during the Parade of Homes!
If you’re a member of the WNC green building council, you got an email today introducing the latest overhaul of the Greenbuilt NC program, and announcing the new net-zero energy and net-zero energy ready options. We have been “test driving” beta versions of the checklist for several months with some of our brave and dedicated builders, and are excited to roll it out to everyone this fall.
So, what’s a Greenbuilt NC “net-zero energy” home? It’s a home that meets all the requirements of Greenbuilt NC (which has above code standards for materials use, site sustainability, water conservation, indoor air quality, and appliances) plus one more: it has enough renewable energy (typically in the form of solar photovoltaics) to achieve a HERS rating of 15 or lower. The HERS rating is a “miles per gallon” type label that homes can earn. A HERS score of 100 corresponds roughly to code-minimum a few years ago. Code-minimum today is probably around 90. Most Energy Star homes without solar earn HERS scores between 50 and 75. Technically, a net-zero energy home (one that produces as much energy annually as it uses) should have a HERS score of zero. But Greenbuilt NC has decided to recognize homes with less than HERS 15 as net-zero because the HERS index is based on typical American usage of the home and its plug loads. Research has shown that up to 30% of home energy usage can be reduced by user behavior, and local experience with many net-zero energy and near net-zero energy homes tells us that an efficiency-minded homeowner can usually operate at net-zero energy with a HERS index of about 15. Since these are the people who most often build or buy net-zero energy homes, it seemed like a great target for the program.
Greenbuilt NC will also be recognizing “net-zero ready” homes. These are homes that achieve HERS scores of 55 or lower, and have suitable roof area and a conduit installed for future solar power. The practical lower limit for energy efficiency is usually between 45 and 55 HERS score. Below that, solar starts to be the less expensive option for increasing efficiency. We also have one home in the parade that is pursuing “net-zero ready” status: 10 Rockcliff Way, in Hendersonville. Built by Living Stone Construction, this home has an amazing geothermal heating/cooling system and one of the most efficient water heaters on the market. I know there’s a lot of cool design to see in this house, but when you visit on the tour, do NOT let this distract you and skip the mechanical room. You should also make a point to notice that this house has some “edison-style” light bulbs that are actually LED – this gets you bonus points in my book! It earned a HERS score of 51.
The three net-zero certified homes are all in West Asheville, and you should definitely make a point of seeing these on the tour as well.
77 Middlemont Avenue, by Mountain Sun Building and Design achieved a HERS index of 10. The builders used a combination of strategies to get there including an ultra-tight building envelope, tankless water heater, all LED lighting, and passive solar design. Other green features of the home include raised gardening beds and water conserving fixtures. This house also achieved Energy Star’s “Indoor air plus” label, which recognizes extensive effort to select low-emitting materials and use construction techniques that promote indoor air quality. Be sure to ask about it when you visit.
108 Hudson Street, by Earthtone Builders achieved a HERS index of 11. It also deserves a shout-out for achieving an amazing HERS 46 prior to the addition of solar PV. They accomplished this by combining a highly insulated home with a hyper-efficient minisplit air conditioning system and radiant floor heating. The design includes clerestories to bring more natural light into the home, and it was designed with aging in place and accessibility at the forefront. Make sure you notice the accessibility features on the tour.
179 Morningside Drive by JAG and Associates Construction achieved a HERS index of 15. These guys have been consistently achieving super-tight blower door tests for many years and are one of Asheville’s most prolific green builders. Make sure you notice the tankless water heater, the sealed crawlspace, and the Energy Star appliances when you tour. If you don’t know a lot about sealed crawlspaces, these are the guys to ask. When we did our final testing, there were also some really cool-looking raised beds in progress out back, so I’m looking forward to seeing those finished myself.
There are at least 14 homes in the Parade that have some form of green certification (That’s half! Way to go Asheville!). These are all great builders, and we’re thankful for every single one of them. If I weren’t so tired from inspecting all those homes, I’d write a description of each and every home. Make sure you visit the homes and be sure to notice all the great features and strategies in the homes. Not everything is easy to see, so be sure to ask.
Copyright 2015. Amy Musser