Now, what exactly is “LEED” again?

LEED stands for Leadership in Energy and Environmental Design. It is the most widely adopted green building standard in the world. First developed by the U.S. Green Building Council in 1993—one of the eight councils that formed the World Green Building Council in 2002—it has evolved over the years to include 10 rating systems that cover commercial buildings, schools, and residential homes, as well as overall neighborhood development. Each of the systems rates a building’s functional and sustainability performance.

Typically, building a LEED home is new construction, and many architects in the region have experience with constructing new LEED homes. Therefore, a new LEED home is a “green field” project for which all the design elements are completed from scratch. There are no existing conditions — a home’s occupants, landscape, old tile, or old plumbing. None of that.

But remodeling a home to qualify for LEED certification is another matter — and our’s is one of those!

LEED is a credit-based system that projects a home’s performance based upon its design and then finalizes a total score once certain performance parameters have been verified by a third party rater. As you can see in the above image, there are four certification classes, each requiring a certain number of points to achieve each certification. Our remodeled home is currently projected to fall within the LEED Platinum certification with a point total of 90+ points, making it the first LEED home of any kind (new or remodeled) in Arlington Heights and one of very few LEED Platinum remodels in the entire Chicago region.

Our third party rater, Eco Achievers, has worked closely with our architect and GC, Mike Kollman as well as both Amy and I directly. They will verify our home’s performance based upon two important inspections that occur midway and at the end of the project and is using the LEED v4.1 BD+C: Single Family system to rate our home.

There are nine categories used by our rating system: Integrative Process, Location & Transportation, Sustainable Sites, Water Efficiency, Energy & Atmosphere, Materials & Resources, Indoor Environmental Quality, Innovation, and Regional Priority. Each category is assigned a certain number of weighted points, which are earned based upon design and the projected performance, all of which will be validated and verified once the project is complete.

One important thing to remember is that some of the categories have prerequisites which must be met before earning any credits for a category. Once that bar is cleared, many of the categories have sub-categories that provide several options for earning credits.

Integrative Process (2 of 2 credits)

It seems pretty straightforward, but we earned the credits for this category by forming an integrated project team that included our architect/GC (who specialized in green building), interior designer, civil engineer, and landscape designer. We’re not sure why one wouldn’t do this, anyway. In November 2019, we also conducted a design charrette at our home (our insistence, because we love to entertain!) that involved all the key stakeholders in the project for a full day’s meeting to go over the entire project’s scorecard and assign responsibilities to each stakeholder for their part in helping us achieve LEED credits.

Additionally, the design charrette exemplified the importance of Community for our project.

Going through the LEED process step-by-step

Location & Transportation (6 of 10 credits)

Required: Cannot build on a floodplain.

Our project is just for our home within an already established suburb that has been developed — we’re not sprawling into another parcel of land or building near a farm, wetland, or a wildlife habitat. However, our home isn’t close enough to a train station and other community resources, so we did not earn the full 10 points.

Sustainable Sites (4 of 5 credits)

Required: Construction activity pollution prevention (install silt fencing and keep construction waste/soil from washing down the sewer)

Our four credits stem from rainwater management and non-toxic pest control. Our front yard will be a rain garden that will capture water from the front roof of the house and the front porch roof while the backyard will have rain gardens.

Water Efficiency (14 of 15 credits… highly possible we’ll earn all 15 credits)

Required: Reduce overall water usage by a minimal percentage and have a water meter.

We could have focused our efforts on indoor water usage by installing new WaterSense toilets, lavatory faucets, and shower heads in all three of our bathrooms (new in our new master bathroom and replacements in our two existing bathrooms), so that each fixture performs at a given flow rate. But to do so would mean we’d have to now consider very limited style options across three very differently styled bathrooms. And, because we’d excluded the two existing bathrooms from the project scope from the beginning, we hadn’t budgeted for two new toilets, two new shower heads, and three new lavatory faucets (our existing 2nd floor bathroom had a double vanity). Much easier to just focus on WaterSense fixtures (a toilet, two shower heads, and two lavatory faucets) in our new master bathroom—we could manage the style choices right from the start! And we’d be installing a new Energy Star rated clothes washer (a Miele, if you’re curious). Thankfully, LEED excludes bathtubs (two) and kitchen faucets (two) from the water efficiency requirements because there’s no such thing as an “efficient” bathtub full of water and it’s not practical at all to “limit” one’s use of a kitchen faucet.

We’d always planned on a landscape that was water efficient by removing almost all our grass from the property and replacing it with native or adaptive species for our area (notably, food producing species in our backyard in the form of fruit trees and raised garden beds). If we’d really been eager to keep our grass (we have been off grass for over a decade), we’d have to install an efficient irrigation system.

However, LEED also provided the option of taking a “performance” path to achieve exemplary water efficiency performance by reducing our overall water usage between 75% to 85%. Taking this path quickly became the obvious choice for us, as our rainwater harvesting system will be capturing roughly 1,300 gallons of water from the front and back roofs of the house as well as the garage terrace. Additionally, we’ll be capturing all the water that doesn’t end up in our rainwater harvesting system in rain gardens in the front yard and back yard.

Essentially, what we’re doing with rainwater harvesting and the rain gardens far exceeds anything we could have done indoors with WaterSense fixtures. Yet, we are still doing WaterSense fixtures in our new master bath, the most interesting of them all is our new Toto Washlet toilet, which has a built-in bidet. Basically, it has a heating element built into its lid (it acts exactly like a tankless hot water heater, actually!) which heats the water from the same cold water supply for the flushing tank. One might think a bidet spraying water to wash one’s posterior would use more water; however, it’s the use of toilet paper that actually uses more water! We’ll do a post on this in the future to also include the bidet attachment we purchased during the pandemic from Hello Tushy! which we plan to attach to the existing toilet in our downstairs bathroom.

Energy & Atmosphere (37 of 40 credits)

Required: Energy Star dishwasher, clothes washer and refrigerator. A whole house electric and gas meter. Homeowner education manual that includes the operation and maintenance of all aspects of the home.

The reason for the credits we’re projected to earn here is because of our annual energy usage. Our home is projected to perform at HERS -8 (to explained in detail in the future) which means our solar panels (working in concert with the home’s tightly built thermal envelope) will generate more electricity than we consume. We have also insulated our hot water pipes to squeeze out a little more efficiency from our Navien tankless hot water heater (which uses natural gas). Basically, the better-insulated the hot water pipes are, the less gas we have to use to keep the water in the pipes hot in-between showers/washing our hands/washing dishes, etc. Once the technology advances far enough that they become more energy efficient, we will eventually upgrade to an all-electric tankless hot water heater.

Materials & Resources (9 of 12 credits)

Required: Use non-tropical, reused, reclaimed, or certified by the US Forest Council wood. Install water-resistant flooring, tub/shower, and building materials.

We are using FSC-certified tropical wood for the garage deck tiles and using water-durable materials to meet the prerequisites.

The credits we’re earning stem from the environmentally preferred material choices we’ve made for our insulation drywall, roofing, siding, cabinets, interior trim, and decking. That basically means each material uses a certain percentage of post-consumer/pre-consumer recycled content in its manufacture. Our choice to use a deconstruction service (which recycles/reuses building materials) versus straight demolition (it all goes to a landfill) and our open-truss framing also contribute to our earned credits.

Indoor Environmental Quality (12 of 18 credits)

Required: Basic ventilation, combustion venting, garage pollutant protection, radon resistant construction, air filtering , and compartmentalization.

Meeting the requirements meant our kitchen’s hood needed to exhaust below 400 cubic feet per minute so we don’t require make-up air. And it meant we’d be installing an energy recovery ventilator (ERV). In our case, it will be Conditioning Energy Recover Ventilation system (CERV), to provide our home’s ventilation.

And, because, we’re using two gas-fueled appliances — a Navien tankless hot water heater and a Napoleon gas fireplace insert — both had to have a sealed combustion chamber (they do) and a sealed air supply (they do) that takes in air from the outside. What that means is that inside air isn’t being drawn into either appliance for combustion and the carbon monoxide given off by combustion is directly vented to the outside (via PVC for the water heater; via the chimney for the fireplace).

We also have an exhaust fan installed in the garage that vents out any carbon monoxide given off by car exhaust.

We’re in Radon zone 2 here in Illinois. And since we’re not touching the foundation slab, we’re already meeting the requirement. We could have installed a passive radon ventilation system for an exemplary performance credit, but the cost outweighed the (unneeded) benefit.

Our CERV will use a filter (we’ll also be writing shortly about a new technology being installed in our CERV… a UV bulb that destroys airborne particles passing through the CERV).

Every penetration in our home (walls, ceilings, floors, etc.) are sealed. All doors and windows are sealed. The tightness of our home’s envelope will be the subject of a “blower door” test performed by our third party rater Eco Achievers to verify we’ve met the compartmentalization requirement. That test will also nail down the precise HERS rating we’ll receive.

And all that above are just the requirements that must be met before any credits can be earned!

The credits we’re projected to earn stem from the CERV’s enhanced ventilation capabilities (MERV 13 filter, VOC, and CO2 detection), contaminant control (walk off mats, shoe removal space, a pre-occupancy air flush of all ducts, and an exhaust fan in garage) and enhanced combustion venting for the water heater and fireplace that we are implementing. Part of these credits also come from the pressure-balanced heating and cooling system we will implement using Mitsubishi minisplits that work in concert with our CERV.

Finally, our use of low-emitting materials will earn the remaining credits in this category. That means the paint, adhesives/sealants, flooring, and insulation used to remodel our house will meet a VOC emissions and content requirement.

Innovation (5 of 6 credits)

Required: Third party must evaluate and approve our innovations.

Our plans for an extensive edible landscape that consists of fruit trees and raised vegetable gardens at grade and on the garage terrace is considered a pilot innovation. The exemplary performance for our choices of environmentally preferred and low-emitting products are also contributing innovations. Finally, the strong community outreach and involvement we’ve emphasized throughout the project has been an important factor.

Regional Priority (3 of 4 credits)

Required: None.

Our regional priority credits stem primarily from the emphasis we’re placing on our overall water consumption. Essentially, we will rely 100% upon rainwater for all our landscape needs and will significantly reduce our municipal water needs by using WaterSense fixtures (the bidet is the major contributing factor!)

So… that’s how LEED works!

But the point isn’t really so much how many credits we receive, but rather that we’re remodeling our home to be as energy efficient, water efficient, healthy, and community-oriented as possible. That’s really been the goal of the Happy Boolo project from the beginning!