Solar Plumbing and Wiring Chase

    Scope Images
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    Plumbing riser detail for solar thermal systems
    Scope

    Install a plumbing and wiring chase from the utility room to the roof space designated for the future solar hot water array Space requirements and layout for solar water heating and photovoltaic system components should be taken into account early in the design process. 

    See the Compliance Tab for related codes and standards requirements, and criteria to meet national programs such as DOE’s Zero Energy Ready Home programENERGY STAR Certified Homes, and EPA Indoor airPLUS.

    Description

    A renewable energy-ready home (RERH) is one that is built with the wiring and plumbing conduit and other components in place to facilitate the future installation of solar photovoltaic panels and/or solar water heating panels. Some energy-efficiency programs, like the U.S. Department of Energy’s DOE Zero Energy Ready Home Program, require homes to be renewable-energy ready.

    To meet the requirements of the DOE Zero Energy Ready Home program, install either a single 4” or two 2” PVC chases from the utility room to the roof space (see Figure 1). The pipe chase should be installed as a straight run and be clearly labeled as an RERH component.

    A single straight 4” pipe chase or two 2” pipe chases installed in a straight run from the utility room to the underside, or attic side, of the designated solar array roof area will allow for the installation of the solar pipes and pipe insulation during the solar system installation. The pipe chase can be made of lightweight PVC or any other code-compliant material that is favored in the local housing market. It is not recommended to use a boxed-in open chase in the wall as other contractors may inadvertently install wires, plumbing, and ductwork through it. The use of a boxed-in open chase may also compromise the integrity of the home’s thermal shell. With this in mind, the chase should be capped on both ends and sealed at all floor and ceiling penetrations to maintain air tightness and mandatory fire ratings.

    A straight pipe chase between the utility room and the attic is the recommended method. Minor horizontal pipe runs at either end of the pipe chase are allowable. However, in situations where the pipe chase between the attic space and the utility room travels at a slope, bends, or terminates in an area lacking sufficient access or in a way that would prevent the continuation of the pipe run to the collector area or solar storage tank, it is recommended that the actual system water pipes be installed between the utility room and the roof area. A certified NABCEP solar professional should be consulted when installing the actual pipe run as opposed to a pipe chase.

    The termination of the pipe chase or pipes should extend above the attic insulation by 6 inches and be located in an area that provides sufficient accessibility and clearance: 18 inches from the top of the chase to the underside of the roof deck. This is so a solar installer can have room to continue the pipe run above the roof deck to the solar array, at a future point in time. If the actual pipes are run to the roof, they must terminate at a universally convenient location relative to the proposed solar array location. The end of the pipe chase or pipes should be labeled to indicate its purpose and intended use.

    How to Install a Pipe Chase for Solar Hot Water

    1. Designate a proposed location and square footage for the solar hot water array on the roof (preferable directly above the utility room).
    2. Install a single 4” chase or two 2” chases from utility room to the attic space below designated array location.
    3. Ensure the chase terminates at least 6” above the attic floor insulation (if applicable) and at least 18” below the attic roof deck.  Cap both ends.
    4. Wrap a 3” x 1” label around the chase so the text is visible and upright (if possible).  The label should read, “Renewable Energy Ready Home – Solar Thermal Pipe Chase.”
    5. Record the pipe chase location on a plumbing riser diagram.
    Plumbing riser detail.
    Figure 1. An accurate plumbing riser detail helps contractors and homeowners understand how all the components of the Consolidated Renewable Energy Ready Home checklist fit together.

     

    Ensuring Success

    Ensure adequate utility room early in the house design process to allow for ample space for solar water heating and photovoltaic system components. 

    Confirm with local code officials early in the design process what steps are needed to ensure that installation of solar water heating panels will meet with local codes, homeowner's association covenants, and historic district regulations. See the article on building codes and regulations related to solar water heating systems at Energy.gov for additional information.

    Protect the electrical and mechanical components of the solar water heating system from bulk moisture, high temperatures, and direct sunlight.  The utility room should be properly ventilated and maintain average indoor temperatures.

    Climate

    The DOE Zero Energy Ready Home PV-Ready Checklist (Revision 07)  is required only under the following condition related to climate (See the Compliance Tab for other exceptions):

    • Location, based on zip code, has at least 5 kWh/m2/day average daily solar radiation based on annual solar insolation using the PVWatts online tool. See map below. 

    In climates where freezing temperatures are likely to occur, a closed-loop anti-freeze system with heat exchanger will keep outdoor water pipes from bursting.

    Average daily solar radiation per month.
    Map of average daily solar radiation per month.

     

    Presentations

    Compliance

    The Compliance tab contains both program and code information. Code language is excerpted and summarized below. For exact code language, refer to the applicable code, which may require purchase from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if you find broken links.

     

    ENERGY STAR Certified Homes

    The ENERGY STAR Certified Homes National Program Requirements for Homes states that “Dwelling units in multifamily buildings with 4 or 5 stories above-grade are eligible to earn the ENERGY STAR if each unit has its own heating, cooling, and hot water systems4, separate from other units, unless the domestic hot water is provided by a solar system.  Then (Footnote 4), “Central systems for domestic hot water are allowed for domestic hot water if solar energy provides at least 50% of the domestic hot water needs for the residential units.”

     

    DOE Zero Energy Ready Home (Revision 07)

    Exhibit 1 Mandatory Requirements.
    Exhibit 1, Item 1) Certified under the ENERGY STAR Qualified Homes Program or the ENERGY STAR Multifamily New Construction Program.
    Exhibit 1, Item 7) Provisions of the Consolidated Renewable Energy Ready Home (RERH) Checklist are completed. 

    The RERH Checklist requires builders to

    • Install a single 4” chase or two 2” chases from utility room to the attic space below designated array location (cap and label both ends). (RERHSWH Guide 3.5)

    DOE recommends but does not require solar thermal water systems. See the DOE Zero Energy Ready Home Solar Hot Water-Ready Checklist (Encouraged)

     

    2009, 2012, 2015, 2018, and 2021 International Energy Conservation Code

    Section 401.3 A permanent certificate shall be posted on or near the electrical distribution panel that lists types and efficiencies of water heating, heating, and cooling equipment, as well as insulation R values, and window U and SHGC factors.

    Retrofit:  2009, 2012, 2015, 2018,  and 2021 IECC

    Section R101.4.3 (in 2009 and 2012). Additions, alterations, renovations, or repairs shall conform to the provisions of this code, without requiring the unaltered portions of the existing building to comply with this code. (See code for additional requirements and exceptions.)

    Chapter 5 (in 2015, 2018, 2021). The provisions of this chapter shall control the alteration, repair, addition, and change of occupancy of existing buildings and structures.

     

    2009, 2012, 20152018, and 2021 International Residential Code (IRC)

    M2301 Solar Energy Systems (Solar Thermal Energy Systems in 2015, 2018, and 2021 IRC)  - See requirements for solar water heating systems.

    20152018, and 2021 IRC

    Appendix U (Appendix T in 2018 IRC and Appendix AT in 2021 IRC) Solar Ready Provisions - Prepare the home for solar installations in accordance with these specifications.

    Retrofit:  2009, 2012, 2015, 2018,  and 2021 IRC

    Section R102.7.1 Additions, alterations, or repairs. Additions, alterations, renovations, or repairs shall conform to the provisions of this code, without requiring the unaltered portions of the existing building to comply with the requirements of this code, unless otherwise stated. (See code for additional requirements and exceptions.)

    Appendix J regulates the repair, renovation, alteration, and reconstruction of existing buildings and is intended to encourage their continued safe use.

     

    2009, 2012, 2015, 2018, and 2021 International Mechanical Code (IMC)

    Follow the requirements for solar water heating systems found in the IMC, Chapter 14, Solar Systems (Solar Thermal Systems in 2018 and 2021 IMC).

    More Info.

    Access to some references may require purchase from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if you find broken links.

    Case Studies
    References and Resources*
    Author(s)
    U.S. Environmental Protection Agency
    Organization(s)
    EPA
    Publication Date
    Description
    The RERH specifications and checklists take a builder and a project design team through the steps of assessing a home’s solar resource potential and defining the minimum structural and system components needed to support a solar energy system.
    Author(s)
    FSEC
    Organization(s)
    FSEC
    Publication Date
    Description
    Website with information for consumers about solar thermal systems for homes.
    Author(s)
    Aldrich
    Organization(s)
    CARB,
    Steven Winter Associates,
    SWA
    Publication Date
    Description
    Brochure on specifications for solar thermal systems.
    *For non-dated media, such as websites, the date listed is the date accessed.
    Contributors to this Guide

    The following authors and organizations contributed to the content in this Guide.

    Building Science Measures
    Building Science-to-Sales Translator

    Solar DHW Ready Home =

    Image(s)
    Technical Description

    Solar hot water systems use energy from the sun to heat water for use in the home. The easiest time to prepare a home for the installation of these systems is during design and construction. A solar hot water-ready home does this by providing plumbing lines from the attic to the hot water heater, chases for wiring, documentation that the roof is designed to support the extra weight of the solar thermal panels, adequate roof space for the solar collector array that is not shaded, and adequate space in the utility room for an additional solar hot water tank, pumps, and controls. 


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