One of the first steps in planning a LEED home is to adjust the certification thresholds based on the material and energy impacts. All else being equal, a large home consumes more materials and energy than a small home over its lifecycle.
One of the first steps in planning a LEED Cincinnati home is to adjust the certification thresholds based on the material and energy impacts. All else being equal, a large home consumes more materials and energy than a small home over its lifecycle. LEED compensates for these impacts by adjusting the thresholds for each award level. Thresholds for smaller-than-average homes are lowered, and thresholds for larger-than-average homes are raised. A home’s threshold for LEED Gold may be 72 points. A 4,500-sq.-ft. home with five bedrooms would be about 85 points.
In the end, the homeowner will have a well built and third-party certified home. Passing the blower door test alone is significant. Blower door tests are used to prove the air sealing quality of the construction. During the test the home is depressurized to -50 Pascal and measurements are recorded throughout the home to verify that outside air isn’t leaking into the home at a rate higher than required. It proves the home won’t be drafty and uncomfortable. It is much better to control the ventilation rather than allowing shoddy construction of leaky vapor barriers to supply fresh air to the home.
The migration from the suburbs to Cincinnati begun in 2002 with a 10-year tax abatement offered on the structure and accelerated in 2007 with an additional five years tacked on for achieving the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) Certification. In 2011 the law changed, so it was a tiered abatement depending on the level of Certification. Certified and up to Silver gave homeowners a tax abatement on $285,000 value of the structure. Gold takes it to $563,000, and Platinum has no cap.
A recent interview with Jason Sather of Cedar Hill Homes, unveiled some interesting facts about their LEED Homes. Jason graduated from Prescott College with a degree in Sustainability and Community Development. This is their second LEED home; the first being on Golden Avenue, which has already achieved LEED Gold.
I interviewed Jason at 1351 Michigan Ave., in the Hyde Park neighborhood of Cincinnati. The home was in the final stages of inspection and touch up. The owners were going to move in the following weekend! It is a large home with four bedrooms and will require 87.5 points to achieve LEED Gold. (Again, as a home grows in size, the number of points gets higher.) To achieve Platinum on the home would require 102.5 points. Achieving Silver is pretty easy for a premium builder that uses quality windows, insulation, sealing, recycling and landscaping. To achieve Gold, a homeowner will have to raise all of those a notch, especially the HVAC efficiencies. Platinum will typically require you to mitigate all stormwater onsite with a leach field or holding tank as well as raising the quality and performance of materials and HVAC.
LEED for Homes
The LEED Certification system is broadly categorized into five equally important parts that demonstrate measurable environmental benefits: Site, Water, Energy, Materials, and Indoor Environment Quality. The following is a review of the features of this home according to the LEED for Homes system.
Prerequisites include building above the 100-year floodplain, not habitat for endangered species, built no closer than 100 feet to water or wetlands, land that wasn’t a public park and land that doesn’t have prime, unique or soils of state significance. Excavated topsoil was reused; runoff was controlled, so it didn’t contaminate storm water sewers or erode hillsides.
The LEED Innovation and Design Process starts with Integrated Project Planning Credits
To maximize opportunities for integrated, cost-effective adoption of green design and construction strategies, Cedar Hill Homes conducted a preliminary LEED for Homes meeting, with the participation of the key members of the project team and Green Building Consultants (the LEED for Homes Certification Provider) to target the level of LEED, select credits and the parties accountable. Typically this includes holding monthly meetings to review project status, introduce new team members to the project goals, discuss problems encountered, formulate solutions, review responsibilities and identify next steps.
To maximize the opportunities for integrated, cost-effective adoption of green design and construction practices they assembled an integrated project team and all team members involved in various project phases. At least one principal member was a LEED for Homes Accredited Professional.
Durability Management Process is all about the materials. It promotes durability of the high-performance building enclosure and its components and systems through appropriate design, materials selection, and construction practices. Prior to construction, the project team will identify risks, responses regarding pests, storm damage and moisture control measures.
The home’s plans include the following features: No paper backed backer board or carpet in tub, shower and spa areas, no carpet within three ft. of the entryway, drain and drain pans for tank water heaters and clothes washers in or over living areas, exhaust conventional clothes dyers directly to outdoors.
Cedar Hill Homes had a quality management process in place to ensure installation and a third-party verified these durability conditions. They also incorporated additional green design and construction features with measurable environmental benefits.
Location and Linkages Credits takes advantage of urban parks and services.
Site selection is a very important aspect of sustainable homes. This home isn’t in a floodplain or built within 100 feet of water or wetlands. The infill site with existing infrastructure didn’t replace prime farmland or parkland and build on habitat or threatened or endangered species. It encourages the building of LEED homes near or within existing communities.
In these examples at least 75 percent of the perimeter immediately borders previously developed land or they built on a previously developed lot. Both were within ½ mile of existing water and sewer lines.
The homes are located close to basic resources such as arts and entertainment center, bank, convenient store, daycare, fire station, cleaner, library, pharmacy, places of worship and schools. They are within ¼ mile of eleven, ½ of 14 and 60 transit rides per weekday. The highly desired urban locations encourage walking, physical activity, and time spent outdoors. They are within one-half or three-quarters of an acre of a public open space.
Although the focus of green building is typically on the built structures located on a site, the design of the site and its natural elements can have a significant environmental impact. Site clearing and earth moving can contribute to considerable runoff, leading to soil erosion and alteration of natural drainage patterns both on and off-site. These credits are automatically granted to high-density construction, in recognition of the fact that compact development enables communities to set aside land for conservation. The homes were placed to minimize drainable pattern changes; construction was scheduled in phases to minimize disturbance and clearly marked areas that not to be disturbed. Maintaining vegetation in those areas.
There were no Invasive Plants in the landscape design which Limited Conventional Turf. The Sustainable Sites category of credits includes landscaping, non-conventional turf, and drought tolerant plants such as Russian sage, lavender, black-eyed susan, hellebore, hosta and arborvitae. Since the provision and distribution of potable water are costly and energy intensive, particularly during dry periods, a more sensible strategy is to design landscaping that requires less potable water.
Local Heat Island Effects were minimized with Surface Water Management, which included Permanent Erosion Controls and Management of Run-off from the Roof. The Sustainable Sites category of credits includes prerequisites to prevent construction runoff from damaging sewers and preserve topsoil. An infill site minimized disturbed area of the site.
The home integrated nontoxic pest control methods by sealing external cracks, joints, etc. with caulking and installed pest –proof screens. There are no wood-to-concrete connections. Typically all cellulosic (wood type) material is treated with borate product to 3 feet above foundation as an additional pest control measure.
The homes made use of compact development patterns on buildable land to conserve land and promote community livability, transportation efficiency and walkability. Some of the homes were of moderate density, which is an average density of seven or more dwelling units per acre and others were very high density defined as an average density of 20 or more dwelling units per acre.
Water Efficiency Credits are an important part of environmental design
Indoor water use was reduced with high-efficiency fixtures and fittings of which the average flow rate is 2 gallons per minute, and 1.30 gallons per flush. Some of the homes have very high-efficiency fixtures and fittings, which mean the average flow rate is 1.75 gallons per minute, and 1.10 gallons per flush.
Energy Efficiency Credits include HVAC and domestic water heating
Data from the homebuilding industry indicate that roughly 1.5 million new homes are built each year and that the average size of new homes has doubled in the past 50 years. As a result, total U.S. fossil fuel use in homes has been steadily increasing. The average American consumes five times more energy that the average global citizen, ten times more than the average Chinese person, and nearly 20 times more than the average Indian. These homes proved the overall energy performance of the home by meeting or exceeding the performance of an Energy Star labeled home. They Exceeded the Energy Star standard by reference to the Home Energy Rating System (HERS) analysis verification of the energy efficiency of the home. A rating of 35 will mean that a home is 65 percent more efficient than a typical home in Cincinnati.
They reduced energy consumption associated with the domestic hot water systems, including improving the efficiency of both the hot water system design and the layout of the fixtures in the home. With Efficient hot water distribution will typically the total length of the circulation loop must be less than 40 feet in one story homes, add 2-times ceiling height for two-story homes and 4x ceiling height for up to four-story homes. Pipe insulation is At least an R4. No ozone-damaging HCFC refrigerants are used in the air conditioning system.
Materials and Resources starts locally
The choice of building materials in important for sustainable homebuilding because of the extraction, processing, and transportation they require. Activities to produce building materials may pollute the air and water, destroy natural habitats and deplete natural resources. Construction and demolition wastes constitute about 40% of the total solid waste stream in the United States.
Material-efficient framing encourages less waste on the job site. The Framing order waste factor limit is defined as the percentage of framing material ordered in excess of the estimated material needed for construction. Materials and resources included framing efficiencies and off-site panelized construction leading to 88 percent of onsite waste diverted from landfills. Offsite panelized construction is similar to a factory-built home in that the quality of construction may be higher because the construction isn’t subject to the weather and the possibility of less highly trained carpenters.
Environmentally preferable products increase demand for environmentally preferable products and products or building components that are extracted, processed, and manufactured within the region. Any tropical wood is required to be Forest Stewardship Certified. Such wood is not harvested by clear-cutting, eliminating an ecosystem that may be tens of thousands of years old. To ensure that, the country of origin was requested for each wood product, a species is considered tropical if it is grown between the Tropics of Cancer and Capricorn. FSC trees are harvested individually, leaving the vast majority of the forest untouched.
The projects reduced waste generation to a level below the industry norm. Cedar Hill Homes investigated and document local options for diversion and measured the diversion. At least 25 percent or more was diverted from landfills.
Indoor Environmental Quality is the most misunderstood environmental benefit of Green Homes
Americans spend an average 90% of their time indoors, where levels o pollutants may run two to five times – and occasionally more than 100 times – higher than outdoors, according to the U.S. Environmental Protection Agency. Many of the pollutants found indoors can cause health reactions in the estimated 17 million Americans who suffer from asthma and 40 million who have allergies, contributing to millions of days absent from school and work.
LEED homes limit the leakage of combustion gases into the occupied space of the home. Indoor environmental quality included no unvented combustion appliances, carbon monoxide detectors in rooms that share a door with the garage; all fireplaces have doors, and space, water-heating equipment is designed with closed combustion. Typically no fireplace or wood stove or one with back-draft prevention, behind glass doors, or catalytic converters is used.
Control indoor moisture levels are controlled to provide comfort, reduce risk of mold and increase the durability of the home. Dehumidification equipment was installed capable of maintaining humidity at or below 60 percent. The homes reduce occupant exposure to indoor pollutants by ventilating with outdoor air. Prerequisites included bathroom and kitchen exhausts meeting ASHRAE Standard 62.2 airflow requirements, air is exhausted to outdoors and an Energy Star labeled bathroom exhaust is used. To meet ASHRAE Standards, air is only exhausted to the outdoors, not the attic or interstitial spaces. The homes enhanced local exhaust credit uses occupancy sensors, automatic humidistat controller, automatic timer or continuous fan. Third-party performance testing ensures proper installation.
Room-by-room load calculations provide appropriate distribution of space heating and cooling in the home to improve thermal comfort and energy performance.
A typical home has improved the distribution of space heating and cooling including a return air opening of 1 sq. inch per cfm of supply and continuous supply air flow rates in each room tested and confirmed. Cedar Hill Homes specified the best air filters MERV 13.
Indoor contaminants where controlled during construction. Home design contaminant control includes design for shoe removal and storage space near the primary entryway. A preoccupancy flush was performed to rid the home of contaminants that built up during the construction process. Radon-resistant construction is required in high-risk areas
Either there is no HVAC in garage or to minimize pollutants from the garage, penetrations and floor and ceiling joists connections are sealed to prevent pollutants from getting into the home. Some homes have a detached garage or no garage.
Awareness and Education is also a way for a home to receive credits. Some homebuyers may know very little about green home construction. They may be unaware of the green features in the home, or they may be unfamiliar with how to use and maintain them. Without adequate training, the full benefits of the LEED measures likely will not be achieved. The homeowners will receive an operator and training manual as well as a one-hour walkthrough. Provide the home’s occupants with LEED checklists and forms, manufacturer’s manuals, and cleaning and maintenance guidance. Cedar Hill Homes also provide two hours of training. Awareness and education requirements include this article as part of the LEED Certification. It will be distributed to the media online at Green Cincinnati Education Advocacy newsletter blog and published on the USGBC’s site once certified. LEED Signage was also posted on the site.
Cedar Hill Homes, http://www.cedarhillcustomhomes.com, Contact Jeff Barnes: 513.509.1506