The LEED for Homes v4 rating system, under IEQ Credit: Contaminant Control, mandates specific measures to prevent the contamination of building systems during construction. After the HVAC rough-in, it is a prerequisite to seal all ductwork openings, including boots, vents, and registers, with plastic or other durable materials. This action prevents construction dust, debris, and other airborne particulates from entering and accumulating within the duct system. Failure to do so would result in the HVAC system becoming a source of indoor air pollution once it is commissioned, distributing contaminants throughout the home and compromising occupant health.

A. A building flush-out is a post-construction procedure performed immediately before occupancy to remove volatile organic compounds (VOCs), not a mid-construction step.

B. Opening windows provides general ventilation but does not specifically protect the interior of the HVAC ductwork from construction dust and debris.

D. Installing temporary fans helps with air circulation but is not the required method for preventing contaminants from entering the newly installed ductwork.

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1. U.S. Green Building Council. (2018). LEED v4 for Homes Design and Construction. Washington, DC: U.S. Green Building Council.

Reference: IEQ Credit: Contaminant Control, Section "During Construction," Requirement 2. The guide explicitly states, "Cover and protect HVAC registers, grilles, and ductwork openings from dust and debris."

2. Kyllo, J. M., & O'Brien, P. (2016). Sustainable Construction and Design. Pearson.

Reference: Chapter 10, "Indoor Environmental Quality," section on Construction IAQ Management Plan. This university-level textbook outlines best practices aligned with LEED, specifying that "all ductwork openings must be sealed during construction to prevent contamination."

3. University of Florida, Program for Resource Efficient Communities. (2015). Construction Best Practices for Florida-Friendly Building.

Reference: Section 4.2, "Indoor Air Quality," page 4-4. This document, used in university extension programs, details construction phase IAQ management: "Seal all supply and return air ducts after rough-in to prevent dust and debris from entering the system."

For LT Credit - Site Selection, Option 3 (Open Space), LEED v4 Homes & Multifamily Low-Rise requires that the project be within ½ mile (800 m) walking distance of one CONTIGUOUS, publicly accessible open-space parcel that is at least 0.2 ha (0.5 acre) and whose primary ground cover is living vegetation. Playgrounds finished mainly in softscape meet the definition. Water surfaces may supply no more than 25 % of the qualifying area, golf-course land is specifically excluded, parcels smaller than 0.2 ha may not be aggregated, and spaces that cannot be freely accessed by the public do not count. Only option A satisfies every stipulation.

B. Dominated by water and part of a golf course; water limited to 25 %, golf courses excluded.

C. Each parcel is <0.2 ha and they are not contiguous; LEED disallows combining separate parcels to meet the minimum.

D. Access requires crossing private property; therefore not “publicly accessible” as required.

1. USGBC. LEED v4 for Homes and Multifamily Low-Rise Reference Guide, Location & Transportation credit – Site Selection, Option 3: Open Space, Req. bullets 1–4, p. 93–94.

2. USGBC. LEED v4 BD+C Reference Guide, Sustainable Sites credit: Open Space, “Qualifying Open Space,” p. 158 (water area & golf-course exclusions align with Homes criteria).

3. University of Washington Built Environments College, Course B E 470 “Green Buildings,” Lecture 7 notes, slide 15 (public accessibility and minimum size for LEED open-space compliance).

The LEED for Homes Indoor Water Baseline Consumption is calculated using a standardized formula that estimates daily water use. This calculation requires three key inputs:

1. Fixture flow rates: The baseline assumes standard flow rates as defined by the Energy Policy Act of 1992 (e.g., 2.5 gallons per minute for showerheads).

2. Number of occupants: In LEED for Homes, the number of occupants is estimated based on the number of bedrooms (Occupants = Number of Bedrooms + 1). This determines the frequency of use.

3. Number of fixtures: The number of bathrooms is used to determine the quantity of water-using fixtures (showers, toilets, faucets) in the home.

B: The size of plumbing piping is a hydraulic design parameter and is not used in the LEED water consumption calculation.

C: The physical size of shower compartments is irrelevant to water use, and this option omits the critical factor of occupant number (bedrooms).

D: Recirculating shower systems are an advanced water-saving strategy considered in the design case, not in the baseline calculation, which assumes standard fixtures.

1. U.S. Green Building Council. (2015). LEED v4 for Homes and Midrise Reference Guide.

Page 169, WE Prerequisite: Indoor Water Use, Step-by-Step Guidance: The guide specifies the calculation methodology. It states, "The number of occupants is assumed to be the number of bedrooms plus one." It also provides a table with baseline (default) fixture flow rates and usage assumptions (e.g., showers: 1 use/person/day). This confirms the necessity of bedroom count and fixture flow rates. The number of bathrooms is required to tally the total number of fixtures for the home's overall baseline.

2. Krygiel, E., & Nies, B. (2016). Green Building: Principles and Practices in Residential Construction.

Chapter 6, Water Efficiency, "Calculating Water Savings": This academic text, often used in university curricula, explains that residential water use baselines for green building certifications like LEED are established using EPAct 1992 flow rates and occupant estimates derived from the number of bedrooms. It details how the number of fixtures (determined by counting them, often by bathroom) is multiplied by usage patterns tied to occupants.

LEED for Homes treats large areas of glazing as a potential energy penalty. Energy & Atmosphere credit “Windows” (both 2008 and v4 Homes & Multifamily Low-Rise guides) states that if the window-to-exterior-wall-area ratio (WWR) is greater than 24 %, the project must meet more stringent whole-unit U-factor and SHGC requirements (Table EA-Windows-1) to earn the credit. Below that threshold, standard ENERGY STAR window specifications are acceptable. The 24 % value is therefore the trigger for the tightened performance, and it is expressed only relative to the exterior-wall area, not the conditioned-floor area.

A. 15 % WWR is below LEED’s high-glazing threshold; normal ENERGY STAR performance suffices.

B. LEED does not determine this credit with a window-to-floor-area ratio.

D. The 24 % threshold is applied to exterior-wall area, not floor area; this metric is not used in the credit.

1. USGBC. LEED for Homes Reference Guide (2008 Edition, rev. 2010), Energy & Atmosphere Credit – Windows, p. 118, “Projects with WWR > 24 % shall meet the enhanced U-factor/SHGC values in Table EA-W-1.”

2. USGBC. LEED v4 Homes & Multifamily Low-Rise Reference Guide (2013), EA Credit: Windows, Section “Increased Glazing Areas,” p. 318, “If window area > 24 % of gross above-grade wall area, use the more stringent U-factor and SHGC shown in Table 2.”

3. DOE / Lawrence Berkeley National Laboratory course note “High-Performance Residential Fenestration” (University of California extension, 2019), §3.2, citing LEED Homes requirement of 24 % WWR threshold for enhanced glazing performance.

The LEED for Homes Rating System (v4) includes a Home Size Adjustment as part of the point-scoring

system to account for the environmental impact of larger homes, which typically use more resources

and energy. This adjustment is applied across the project’s total points and is calculated based on

conditioned floor area and the number of bedrooms.

According to the LEED Reference Guide for Homes Design and Construction (v4):

Home Size Adjustment

The Home Size Adjustment modifies the total points required for certification based on the

conditioned floor area and number of bedrooms, as larger homes have greater environmental

impacts. The adjustment is applied to the overall point threshold, not to a specific credit, but it aligns

with credits like Indoor Environmental Quality (EQ) Credit: No Environmental Tobacco Smoke, which

ensures indoor air quality in larger homes.

Source: LEED Reference Guide for Homes Design and Construction, v4, Introduction, p. 24.

The LEED v4.1 Residential BD+C rating system confirms:

Home Size Adjustment

The adjustment uses conditioned floor area and number of bedrooms to scale certification

thresholds, ensuring fairness across home sizes. It impacts the overall certification process,

particularly in relation to credits like EQ Credit: No Environmental Tobacco Smoke, which addresses

indoor air quality in larger spaces.

Source: LEED v4.1 Residential BD+C, Credit Library, accessed via USGBC LEED Online.

The correct answer is Indoor Environmental Quality Credit, No Environmental Tobacco Smoke

(Option C), as the Home Size Adjustment influences the overall point requirements for certification,

and this credit is relevant to ensuring air quality in homes of varying sizes.

Why not the other options?

A . Water Efficiency Credit, Indoor Water Use: This credit focuses on fixture efficiency and water use

calculations, not directly tied to home size adjustment.

Reference: LEED Reference Guide for Homes Design and Construction, v4, WE Credit: Indoor Water

Use, p. 96.

B . Materials and Resources Credit, Construction Waste Management: This credit addresses waste

diversion, not home size or bedroom count.

Reference: LEED Reference Guide for Homes Design and Construction, v4, MR Credit: Construction

Waste Management, p. 164.

D . Location and Transportation Credit, Access to Transit: This credit focuses on proximity to transit,

unrelated to home size or bedrooms.

Reference: LEED Reference Guide for Homes Design and Construction, v4, LT Credit: Access to Quality

Transit, p. 58.

The LEED AP Homes Candidate Handbook emphasizes the Home Size Adjustment as part of the

certification process and

the LEED Reference Guide for Homes Design and Construction as

a key resource. The exam is based on LEED v4, ensuring the relevance of this adjustment.

References:

LEED Reference Guide for Homes Design and Construction, v4, USGBC, Introduction, p. 24.

LEED v4.1 Residential BD+C, USGBC LEED Credit Library, accessed via LEED Online

(https://www.usgbc.org/credits).

LEED AP Homes Candidate Handbook, GBCI, October 2024, p. 12 (references study resources and

exam scope based on LEED v4).

USGBC LEED for Homes Rating System (v4), available via USGBC website

(https://www.usgbc.org/resources/leed-homes-design-and-construction-v4).

LEED v4.1 for Homes, USGBC, accessed via LEED Online, confirming home size adjustment criteria.

The LEED for Homes v4 rating system, under MR Credit 2: Environmentally Preferable Products, allows projects to earn points by using materials that meet specific environmental criteria. Siding is one of the eligible product categories. To earn the first tier of points (0.5 points) for this category, at least 50% of the product, calculated by cost or area, must be an Environmentally Preferable Product (EPP). The prompt states that 50% of the home's exterior is clad with salvaged brick. "Salvaged" or "reclaimed" materials are a primary type of EPP. Therefore, the project already meets the 50% threshold with the brick alone, qualifying it to earn a point.

A. All of the siding is FSC-certified: This is incorrect because 50% of the siding is brick, which is a masonry product and cannot be Forest Stewardship Council (FSC) certified.

B. Cladding combinations cannot earn points: This is incorrect. The LEED rating system is designed to accommodate mixed material assemblies and provides calculation methodologies for such combinations.

D. At least half of the wood siding is both reclaimed and local: This is not a requirement. While this would contribute to the EPP calculation, the project already qualifies for points based solely on the 50% salvaged brick.

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1. U.S. Green Building Council. (2018). LEED v4 for Homes Design and Construction.

Page 109, "MR Credit 2: Environmentally Preferable Products, Step-by-Step Guidance, Step 2. Identify EPPs": This section lists the attributes that qualify a product as an EPP. The first attribute listed is "Reused or salvaged materials," which directly applies to the salvaged brick in the scenario.

Page 111, Table 11, "MR Credit 2: Environmentally Preferable Products": This table outlines the points available for different product categories. For "Siding," it explicitly states that a project earns 0.5 points if ≥50% of the siding is an EPP, and 1 point if ≥90% is an EPP. The scenario meets the 50% threshold.

2. Krygiel, E., & Nies, B. (2016). Green BIM: Successful Sustainable Design with Building Information Modeling. Sybex. (Note: While a commercial book, its detailed breakdown of LEED credits is often used in university courseware for architecture and sustainable design).

Chapter 7, "Materials and Resources": This chapter explains that the EPP credit in LEED for Homes is calculated based on meeting percentage thresholds for specific building components, such as siding. It confirms that salvaged materials are a key compliance path and that calculations are based on the total component assembly, allowing for combinations of materials.

The Regional Priority (RP) credit category awards a bonus point for achieving a specific, pre-existing LEED credit that the USGBC has designated as particularly important for a project's geographic location. For credits that offer a range of points based on multiple performance thresholds (e.g., achieving 25% vs. 40% energy cost savings), the single RP bonus point is earned as soon as the project meets the requirements for the minimum threshold of that credit. The intent is to incentivize addressing the regional concern, and achieving the credit at any level fulfills this intent.

B. Points are awarded at the maximum threshold: This is incorrect. The RP point is awarded for achieving the credit, regardless of the specific threshold met, as long as the minimum is achieved.

C. Points are awarded when the maximum threshold has been exceeded: This is incorrect. LEED awards points for meeting defined thresholds, not for exceeding them, and the RP credit is tied to simply achieving the base credit.

D. Points are awarded at particular levels of achievement: This is too vague. The rule is specific: the bonus point is awarded upon meeting the first level of achievement (the minimum threshold) for the designated credit.

1. U.S. Green Building Council. (2021). LEED v4 for Homes Design and Construction Reference Guide. Washington, DC: U.S. Green Building Council.

Reference: Page 19, "Regional Priority" section, under "How It Works," states: "For credits with multiple thresholds, the regional priority credit is earned when the project earns the credit, regardless of the threshold achieved." This confirms that meeting the minimum threshold to earn the credit is sufficient to also earn the RP point.

The LEED for Homes rating system references ASHRAE Standard 62.2, "Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings," for ventilation requirements. Under this standard, local mechanical exhaust for bathrooms must meet a minimum airflow rate. For intermittent systems (i.e., those controlled by a switch or timer), the required rate is 50 cfm. This requirement is a fixed value for all bathrooms and is not dependent on the size of the dwelling unit, the number of bedrooms, or the square footage of the bathroom itself.

A. 25 cfm is incorrect. The minimum rate for continuous bathroom exhaust is 20 cfm, but the question specifies an intermittent system.

C. The requirement is a fixed airflow rate (cfm), not a variable rate based on the bathroom's floor area (cfm per ft²).

D. The requirement is a fixed airflow rate (cfm), not a variable rate based on the bathroom's floor area (cfm per ft²).

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1. U.S. Green Building Council. (2021). LEED v4.1 Homes and Multifamily Reference Guide. Washington, DC: U.S. Green Building Council. Page 288, EQ Prerequisite: Minimum Indoor Air Quality Performance, Step-by-Step Guidance, Option 1, which requires compliance with ASHRAE 62.2-2016.

2. ASHRAE. (2016). ANSI/ASHRAE Standard 62.2-2016: Ventilation and Acceptable Indoor Air Quality in Residential Buildings. Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers. Section 5.3, Local Mechanical Exhaust, and Table 5.1, "Minimum Local Exhaust Airflow Rates," which explicitly lists "Bathrooms - Intermittent" as requiring 50 cfm.

3. Sherman, M. H. (2005). ASHRAE Standard 62.2-2004: A Standard for Residential Mechanical Ventilation. Lawrence Berkeley National Laboratory. LBNL-58132. Page 5, Table 2, "Local Ventilation Exhaust Airflow Rates." (This earlier version, foundational to later editions, also specifies 50 cfm for intermittent bathroom exhaust). DOI: https://doi.org/10.2172/885111

The intent of the Innovation (IN) Prerequisite: Preliminary Rating is to formalize the goal-setting process at the beginning of a project. By requiring the project team to complete a preliminary LEED for Homes checklist and establish a target certification level, this prerequisite ensures that sustainable goals are integrated into the project from the earliest stages. This early planning is the foundation of the integrative process, which is proven to be the most effective way to identify and implement green strategies, optimize performance, and manage costs. It allows the team to evaluate synergies between credits and make informed decisions before design and construction are too far advanced.

A. This is a potential outcome of the integrative process facilitated by the prerequisite, but not the primary, overarching intent itself.

B. The certification level established is a target, not a mandatory or binding declaration; it can be adjusted as the project evolves.

D. This describes the intent of the Innovation (IN) credits, which reward exemplary performance and new strategies, not the prerequisite for a preliminary rating.

1. U.S. Green Building Council. (2021). LEED v4.1 Homes and Multifamily Reference Guide. Washington, DC: U.S. Green Building Council. Page 431, "IN Prerequisite: Preliminary Rating," under the "Intent" section, states: "To facilitate the integrative process and maximize the opportunities for integrated, cost-effective adoption of green design and construction strategies."

2. U.S. Green Building Council. (2008). LEED for Homes Rating System. Washington, DC: U.S. Green Building Council. Page 111, "ID Prerequisite 1: Preliminary Rating," the "Intent" section states: "To help the project team set goals and integrate the LEED for Homes process throughout the design and construction of the home." This earlier version also emphasizes the core concept of early integration.

3. Krygiel, E., & Nies, B. (2008). Green BIM: Successful Sustainable Design with Building Information Modeling. Wiley Publishing, Inc. Chapter 2, "The Integrative Design Process," discusses how early goal-setting and analysis, as mandated by prerequisites like the Preliminary Rating, are fundamental to achieving cost-effective sustainable outcomes.

The LEED for Homes v4 rating system addresses acoustic comfort by setting maximum sound levels for mechanical ventilation to ensure occupants are not discouraged from using it due to noise. Under the Indoor Environmental Quality (EQ) credit for Indoor Contaminant Control, a requirement for earning the point is that all bathroom exhaust fans must have a maximum sound rating of 1.0 sone. This ensures that the fans can operate effectively to remove moisture and pollutants without creating an acoustically disruptive environment, thereby balancing indoor air quality with occupant comfort.

A. 0.5: This is a quieter performance level than the LEED maximum; while a 0.5 sone fan would comply, it is not the specified threshold.

C. 2: This sound level exceeds the maximum 1.0 sone rating permitted for bathroom exhaust fans to meet the credit requirements.

D. 3: This is the maximum sone level specified for kitchen exhaust fans (range hoods), not for the quieter bathroom environment.

1. U.S. Green Building Council. (2016). LEED v4 for Homes Design and Construction. Washington, DC: U.S. Green Building Council. Page 131, EQ Credit: Indoor Contaminant Control, Option 2. Local Exhaust, Requirement 2.

2. U.S. Green Building Council. (2020). LEED v4.1 Residential Single Family. Washington, DC: U.S. Green Building Council. Page 111, EQ Credit: Enhanced Indoor Air Quality, Option 2. Local Exhaust, Requirement 2.

3. University of Florida, Program for Resource Efficient Communities. (n.d.). LEED for Homes v4 Project Checklist. Page 10, EQ Prerequisite: Indoor Contaminant Control. Retrieved from the University of Florida's official domain, which specifies, "All bathroom exhaust fans are ENERGY STAR qualified or have a maximum sound rating of 1.0 sone."