Architectural Drawings for Solar Photovoltaic Systems

Scope

Provide an architectural drawing and riser diagram for the homeowner showing the planned location for future photovoltaic and solar hot water system components.  Space requirements and layout for photovoltaic and solar water heating system components should be taken into account early in the design process. 

DOE Zero Energy Ready Home Notes

The U.S. Department of Energy (DOE) Zero Energy Ready Home National Program Requirements includes in Exhibit 1, Mandatory Requirements, Item 7 Renewable Ready, that all homes must meet the requirements in the Consolidated Renewable Energy Ready Home (RERH) Checklist.

The RERH Checklist requires builders to:

Provide architectural drawing and riser diagram of RERH solar PV system components and solar hot water components.

Alternative: Provide home buyer with the following information:

  • List of renewable-ready features
  • Available free roof area within +/- 45° of true south
  • Location of panel or blocking for future mounting of PV and SWH components
  • Location of Riser
  • Location of Breaker or slot for future breaker in electrical service panel
  • Copy of the Consolidated RERH Checklist
  • A copy of the RERH Solar PV Specification Guide
  • A copy of the RERH Hot Water Specification Guide.

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 (PV) 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, provide an architectural drawing and riser diagram of RERH solar PV system components and solar hot water.

Develop architectural drawings and diagrams that summarize the installed system equipment (conduit, etc.) as detailed below (see Figure 1). These drawings should accurately represent the installed elements of the system and should be provided to the homeowner (likely to be used by future solar installer for obtaining a building permit).  In addition, the homeowner should be provided with a one-line electrical riser diagram of the PV system components. The diagram should have sufficient detail to clearly identify:

  • Configuration of the PV array
  • Conduit size and type
  • Electrical service panel location and dedicated circuit breaker slots
  • Length of conduit from the designated array location to the designated inverter location
  • Location and number of necessary pull boxes in line with each conduit run
  • Length of conduit from the designated inverter location to the electrical service panel
  • Location of the Balance-of-System (BOS) components

The drawings should also contain information about the PV array mounting system and identify the specifications for the major equipment including manufacturer, model and installation details.

PV system drawing example

Figure 1. PV system drawing example.

When designing the system, always follow the recommendations of all local and national codes as well as manufacturer’s recommendations.

 

Ensuring Success

Ensure adequate utility room early in the house design process to allow for ample space for solar photovoltaic (PV) and water heating system components.  Confirm with local code officials early in the design process what steps are needed to guarantee that installation of PV panels will meet with local codes, homeowner's association covenants, and historic district regulations.

Protect the electrical and mechanical components of the PV system from bulk moisture, high temperatures, and direct sunlight.  The utility room should be properly ventilated and maintain average indoor temperatures.  Proper clearances and working spaces should also be maintained.

Climate

Among other things, the Consolidated Renewable Energy Ready Home (RERH) Checklist is required only under the following condition related to climate:

-    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.

Average daily solar radiation

Training

Right and Wrong Images

None Available

Presentations

  1. Zero Energy Ready Home Training
    Author(s): Rashkin
    Organization(s): DOE

Videos

None Available

CAD Images

None Available

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.

DOE Zero Energy Ready Home (ZERH) Program

The DOE ZERH Consolidated Renewable Energy Ready Home (RERH) Checklist states “Provide architectural drawing and riser diagram of RERH solar PV system components and solar hot water components."

Alternative: Provide home buyer with the following information:

  • List of renewable-ready features
  • Available free roof area within +/- 45° of true south
  • Location of panel or blocking for future mounting of PV and SWH components
  • Location of Riser
  • Location of Breaker or slot for future breaker in electrical service panel
  • Copy of the Consolidated RERH Checklist
  • A copy of the RERH Solar PV Specification Guide
  • A copy of the RERH Hot Water Specification Guide“

Homes that already have a solar photovoltaic (PV) system installed do not need to meet the PV requirements of the Consolidated RERH checklist.

DOE Zero Energy Ready Home National Program Requirements Mandatory Requirement 7 (Renewable Ready) shall be met by any home certified under the DOE Zero Energy Ready Home program, only where all of the following conditions are met:

  1. Location, based on zip code has at least 5 kWh/m2/day average daily solar radiation based on annual solar insolation using PVWatts online tool, AND;
  2. Location does not have significant natural shading (e.g., trees, tall buildings on the south-facing roof, AND;
  3. Home as designed has adequate free roof area within +/-45° of true south as noted in the table below. Note that in some cases a house may have insufficient roof area for the Solar Electric RERH checklist, but it may still have the minimum roof area for the solar thermal RERH Checklist and would therefore have to comply with the Solar Thermal RERH checklist. In other cases, the home may only have adequate south facing roof for the Solar Electric or Solar Thermal RERH Checklist, but not both. In that case the builder can decide which one of those two checklists to apply.

2009 IECC

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.

2012 IECC

Section R 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.

2009 IRC

Follow the requirements for solar water heating systems found in the 2009 IRC Section M2301 Solar Energy Systems.

2012 IRC

Follow the requirements for solar water heating systems found in the 2009 IRC Section M2301 Thermal Solar Energy Systems.

2009 International Mechanical Code (IMC)

Follow the requirements for solar water heating systems found in the 2009 IMC, Chapter 14, Solar Systems.

2012 International Mechanical Code (IMC)

Follow the requirements for solar water heating systems found in the 2012 IMC, Chapter 14, Solar Systems.

2014 National Electric Code (NEC)

Follow the requirements for solar photovoltaic (PV) systems found in the 2014 National Electric Code (NEC), Article 690, PV Power Systems, and Article 110, Requirements for Electrical Installations.

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

  1. Author(s): PNNL, ORNL
    Organization(s): PNNL, ORNL
    Publication Date: December, 2010

    Case study about a 20-unit community of energy-efficient duplexes in Massachusetts that incorporated solar water heating and photovoltaics.

References and Resources*

  1. Author(s): Baechler, Gilbride, Ruiz, Stewart, Love
    Organization(s): PNNL, ORNL
    Publication Date: June, 2007
    Report providing an introduction to current photovoltaic and solar thermal building practices.
  2. Author(s): DOE
    Organization(s): DOE
    Publication Date: April, 2017

    Standard requirements for DOE's Zero Energy Ready Home national program certification.

  3. Author(s): Aldrich
    Organization(s): CARB, Steven Winter Associates
    Publication Date: March, 2013
    Brochure on specifications for PV systems.
  4. Author(s): Brooks, Dunlop
    Organization(s): NABCEP
    Publication Date: March, 2012
    This Photovoltaic (PV) Installer Resource Guide is an informational resource covering basic requirements for PV installations intended for individuals pursuing the Photovoltaic Installer Certification credential offered by the North American Board of Certified Energy Practitioners (NABCEP).
  5. Author(s): BSC
    Organization(s): BSC
    Publication Date: June, 2006
    Report aiming to "de-mistify" technology and economic considerations of residential PV systems.
  6. Author(s): EPA
    Organization(s): EPA
    Publication Date: January, 2011

    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.

Contributors to this Guide

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

Last Updated: 08/04/2014

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