The goal of this requirement is to allow easy installation of HPWH when the existing gas water heater needs to be replaced. HPWH typically requires a 240-volt circuit, and this requirement allows an electrician to easily convert the 120-volt circuit to a 240-volt circuit.

The electrical receptacle must be installed with 3 feet from the water heater. It should be connected to a dedicated circuit with a 10 AWG copper branch circuit. The ends of the unused conductor must be labeled as “spare” and be electrically isolated.

A reserved single-pole circuit breaker space must be placed in the electrical panel next to the circuit breaker for the branch circuit and labeled with the words “Future 240V Use.”

The requirement for the condensate drain being placed near the water heater and no higher than the base of the tank allows the condensate to be removed without relying on a sump pump.

5.3.6.1 Pipe Insulation for All Buildings

§150.0(j)1 

All domestic hot water piping shall be insulated as specified in Section 609.11 of the California Plumbing Code, which requires pipe insulation thickness equal to or more than the diameter of the pipe, up to 2 inches. Above pipe diameter of 2 inches, the insulation thickness must be at least 2 inches.

All domestic hot water pipes that are buried below grade must be installed in a waterproof and noncrushable casing or sleeve. The installation shown in Figure 5-4 below would not meet the installation requirements since it is not insulated. In addition, in Figure 5-4 the hot and cold water lines are not separated. Heat transfer will occur, resulting in energy loss and causing condensation on the cold water line.

Figure 5-4: Noncompliant Below-Grade Piping and Hot and Cold Water Lines Separation

Source: Davis Energy Group/Frontier Energy

1. Piping Exempt From the Mandatory Insulation Includes:
   1. Factory-installed piping within space conditioning equipment.
   2. Piping that serves process loads, gas piping, cold domestic water piping (other than within 5 feet of the water heater), condensate drains, roof drains, vents, or waste piping.
   3. Piping that penetrates framing members. This piping is not required to have insulation where it penetrates the framing. However, if the framing is metal, then some insulating material must prevent contact between the pipe and the metal framing.
   4. Piping located within exterior walls that are installed so that piping is placed inside wall insulation. Wall insulation may be an acceptable alternative insulation method for sections of pipes that would otherwise need pipe insulation, as long as the wall insulation in the walls where the pipes are located meets the requirements of QII and the pipes are roughly centered in the wall cavity. (see Reference Appendix RA4.4.1).
   5. Piping surrounded with at least 1 inch of wall insulation, 2 inches of crawl space insulation, or 4 inches of ceiling insulation. For pipes buried in attic insulation, piping may not be placed directly in contact with sheetrock and then covered with insulation to meet this requirement.
2. Other installation information:
   1. Insulation must be at least 6 inches away from the flue. If possible, bend the pipe away from the flue. Otherwise, it may be necessary to stop pipe insulation short of the storage tank. (See the current version of the California Mechanical Code.)
   2. All pipe insulation seams must be sealed.
   3. Installed piping may not be located in supply or return air plenums. (See the current version of the California Mechanical Code.)
   4. Hot and cold water piping, when installed in parallel runs, must be at least 2 inches apart. (See Reference Appendix RA4.)
   5. If a fire wall interrupts the first 5 feet of pipe, the insulation may be interrupted at the wall and continued on the other side.
   6. Insulation for pipe elbows should be mitered and insulation for tees should be notched. (See Reference Appendix RA4.)

Figure 5-5: Pipe Insulation Requirements First Five Feet From Water Heater

Source: California Energy Commission

Insulation properties are given (inches and R-value) by fluid temperature (degrees Fahrenheit) and nominal pipe diameter (inches).

   Source: Excerpt From Table 120.3-A of the Energy Codes

§150.0(j)2 

If hot water piping insulation is exposed to weather, it must be protected from physical damage, ultraviolet (UV) light deterioration, and moisture. Insulation is typically protected by aluminum, sheet metal, painted canvas, plastic cover, or a water-retardant coating that shields from solar radiation. Adhesive tape should not be used as insulation cover because removal of the tape will damage the integrity of the original insulation during preventive maintenance.

Example 5-2 − Distribution Systems

Question:

When I'm insulating the pipes for a recirculating water heating system, I understand that I must insulate the entire length of hot water pipes that are part of the recirculation loop. Do I also need to insulate the runouts?

Answer:

Yes, per the California Plumbing Code, all domestic hot water piping shall be insulated.

Example 5-2 − Recirculation System Insulation

Question:

Can I get pipe insulation credit for a recirculating water heating system?

Answer:

Not for systems serving a single dwelling unit. Recirculating water heating systems have a mandatory insulation requirement for the recirculating section. . All the circulation loop pipes in one location type (for example, inside, outside, underground) must be insulated to the higher level to qualify.

Example 5-3 − Pipe Insulation

Question:

I thought I was supposed to insulate the first 5 feet of hot and cold water piping from the water heater. Did I misunderstand?

Answer:

Yes. Prior code cycles did require this but based on Section 609.11 of the California Plumbing Code, all domestic hot water pipes must be insulated. There is no requirement for cold water pipes to be insulated.