Provide an architectural drawing and riser diagram for the homeowner showing the planned location for future solar hot water and photovoltaic system components. 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 program, ENERGY STAR Single-Family New Homes, and Indoor airPLUS.
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.
When constructing a home to be renewable energy ready, develop architectural drawings and plumbing riser diagrams that summarize the installed system equipment (pipe chase, etc.). The drawings should accurately represent the installed elements of the system during the final inspection of the house; these drawings should be included in the homeowner education packet.
To meet the requirements of the DOE Zero Energy Ready Home program, the builder should provide a basic architectural drawing to the homeowner summarizing where the equipment is located within the house (see Figure 1). The builder should also provide the homeowner with a plumbing riser detail of the solar water heating system components. This diagram should have sufficient detail to clearly identify:
- Pipe chase size and type
- Length of chase from the designated roof/attic termination point to the utility room
- Designated location and allotted space size of future hot water tank
- Designated location and allotted space size of pump package mounting panel.
How to Create an Architectural Drawing for Solar Hot Water:
- Create a plumbing riser diagram like the one shown in Figure 1 that includes all of the following components of the solar hot water system:
- Proposed location and square footage for the solar hot water panel array on the roof (preferably directly above the utility room)
- Pipe chase from attic to utility room with size, type, and location clearly indicated.
- Utility room space that contains
- 3’ x 3’ x 7’ extra space for a solar hot water heater
- a 3’ x 2’ plywood panel mounted on the wall adjacent to the solar hot water tank location for balance of system components
- a solar bypass valve on the cold inlet to the existing water heater
- access to the plumbing and wiring chase that extends to the proposed solar thermal panel array on the roof.
Ensure adequate utility room size and location for solar water heating and photovoltaic system components early in the house design process.
Confirm with local code officials early in the design process what steps are needed to guarantee 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.
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 a heat exchanger will keep outdoor water pipes from freezing and bursting.
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.
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 DOE Zero Energy Ready Home PV-Ready Checklist are Completed.
DOE recommends but does not require solar thermal water systems. See the DOE Zero Energy Ready Home Solar Hot Water-Ready Checklist (Encouraged).
Section R401.3 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.
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.
M2301 Solar Energy Systems (Solar Thermal Energy Systems in 2015 and 2018 IRC) - See requirements for solar water heating systems.
Section N1101.3 (Section N1107.1.1 in 2015 and 2018 IRC). 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.)
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.
Follow the requirements for solar water heating systems found in the IMC, Chapter 14, Solar Systems (Solar Thermal Systems in 2018 IMC).
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.
The following authors and organizations contributed to the content in this Guide.
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.