FYI > California Title 24 Rinnai America Corporation ("RAC") prepared the below summary of California Title 24, primarily based on the California Energy Commission s 2013 Building Energy Efficiency Standards. The purpose of this document is to provide a general overview of the requirements of California Code of Regulations (CCR) Title 24. This document is offered for informational purposes only as a broad summary of information provided by California Energy Commission; it is not a legal document. What is Title 24? Title 24 references numerous state regulations that govern the design and construction of buildings and facilities as well as energy conservation. Within Title 24, there are multiple sections, each of which reference specific requirements concerning the codes for Electrical, Mechanical, Plumbing, etc. To ensure proper compliance, you should refer directly to CEC Title 24 or contact a professional certified in this area. Title 24 Compliance Title 24 breaks down energy use in buildings into several categories: space heating, space cooling, water heating and lighting. Since usage is impacted by climate conditions in the different areas of the State, the calculations will vary by Zone. The 16 Zones are shown in the below map provided by T24-Reports.com. Title 24 provides two methods for compliance: (1) Prescriptive Method: Each individual component of the proposed building must meet a prescribed minimum energy requirement. Certain requirements define maximum levels, such as maximum number of windows allowed. While it is the simplest approach, it is also the least flexible for compliance and is typically only used in 5-10% of the applications. (2) Performance Method: Also known as the computer method, requires a detailed total accounting of a building s energy usage. The budget for the proposed house is compared to a standard that not only considers the type of energy that is used (electricity, gas, or propane), but also when it is used. Unlike the Prescriptive Method, the overall valuation can then be manipulated with trade-offs, upgrades or downgrades of conservation features. While this approach requires the most effort, it also provides the greatest flexibility and as such is typically used in 90-95% of the applications.
HERS, RESNET and Title 24 To achieve compliance with the Title 24 Standards, some buildings require diagnostic testing or field verification of energy efficient systems or devices by a HERS (Home Energy Rating System) to determine compliance. HERS is a nationally recognized index developed by the Residential Energy Services Network (RESNET) and reflects a home's energy efficiency similar to the standards that are employed by the California s Title 24. Water Heating Equipment and Distribution Systems Within the CCR Plumbing Code, there are minimum standards for water heating equipment and hot water distribution systems. The water heating budget is based on minimum energy factors that appear in the CCR 2013 Residential Compliance Manual, Table 5.1 at right. The use of tankless water heaters provides an opportunity for potential energy savings. The chart below right, provided by Title 24, Inc., reflects estimated percent savings of a tankless water heater over a standard 50 gallon gas fired water heater. The energy impact of the hot water distribution system is also a key component of the overall system calculations and can vary widely based on the type of system, type of configuration, quality of installation and house design. Hot water distribution systems are broken down into two main categories based on application: 1) One or more water heating systems serving a single dwelling unit (includes single family homes and dedicated water heating systems serving a single dwelling unit in multifamily and hotel/motel buildings) 2) Multi-family central distribution systems (One or more central water heaters serving multiple dwelling units). Percentage of Improvement over Standard 50 Gallon Gas-fired Water Heater with.62 EF Climate Zone 6 Los Angeles & Orange County Coastal Climate Zone 7 San Diego Coastal Climate Zone 8 Orange County Inland Climate Zone 9 Los Angeles County Inland Climate Zone 10 San Bernardino & Riverside Counties Climate Zone 14 High Desert Climate Zone 15 Low Desert Non-Condensing Tankless Condensing Tankless (.82 EF) (.94 EF) 10.20% 16.00% 9.50% 14.70% 7.30% 11.30% 6.40% 3.30% 9.80% 4.90% 7.50% 5.20% 3.10% 4.50%
There are many types of configurations that may be used. The impact on the overall calculations of various methods is reflected in CCR 2013 Residential Compliance Manual, Table 5-7 at right. The incorporation of recirculation into the overall water heating distribution system design has become more popular due to its water conservation potential, but it comes at a cost to the overall Title 24 energy compliance. There are many different options available. However, all have a multiplier greater than 1.0 due to the fact that the Title 24 Standard is based on a system without recirculation. The code defines the different recirculation systems as follows: Recirculation w/non-demand controls (R-ND) This option includes all recirculation controls with the exception of demand recirculation control systems. The active control shall be either: timer, temperature, or time and temperature. Timers shall be set to less than 24 hours. The temperature sensor shall be connected to the piping and to the controls for the pump. This method has the largest multiplier as it assumes worst case which would be the pump running nearly 24-hours continuous. Demand Recirculation; Sensor Control (R-DAuto) Demand controlled recirculation systems shall operate on-demand, meaning that pump operation shall be initiated shortly prior to the hot water draw. The controls shall operate on the principal of shutting off the pump with a sensed rise in pipe temperature (Delta-T). For this measure, a sensor control is used to activate the pump rather than a manual control. Better than R-ND, but still can operate beyond actual use; therefore, it has negative impact on overall Title 24 compliance. Demand Recirculation; Manual Control (R-Dman) Demand controlled recirculation systems shall operate on-demand, meaning that pump operation shall be initiated shortly prior to the hot water draw. The controls shall operate on the principal of shutting off the pump with a sensed rise in pipe temperature (Delta-T). A manual switch is used to activate the pump. While better than other methods mentioned above, since the Standard (as shown on Table 5-7) is a system with no recirculation at all, R-Dman has a negative impact on the overall Title 24 compliance. 2013 Title 24 Highlights and the Impact on Different Systems One or more water heating systems serving a single dwelling unit: New Mandatory Requirements for New Construction include: a) A 120V receptacle that is within 3 feet of the water heater and accessible to the water heater with no obstructions. b) A condensate drain that is no more than 2 inches higher than the base of the installed water heater, and allows natural draining without pump assistance. c) A gas supply line with a capacity to provide at least 200,000 Btu/hr to the water heater.
d) Pipe insulation is a mandatory requirement in the following cases: 1. The first 5 feet of hot and cold water pipes from the storage tank or water heater. 2. All piping with a nominal diameter of ¾ or larger. 3. All piping within a domestic hot water recirculation system regardless of the pipe diameter. This excludes branches off of the recirculation loop that are less than ¾ diameter or do not serve the kitchen. 4. Piping from the heating source to a storage tank or between tanks. 5. All hot water pipes from the heating source to the kitchen fixtures. With the exception of item d, all of the above measures are designed to make the dwelling unit High Efficiency Ready for upgrades to the hot water system. It is significantly more cost effective to install these items at time of initial construction. Addition of new mandatory pipe insulation requirements is seen as an opportunity to minimize heat loss in the distribution system. New Prescriptive Requirements: With the changes in the 2013 standards, in a single family residence when using the prescriptive method, for a system with a single gas or propane instantaneous water heater without a storage tank one must have: a) A gas input rating < 200,000 Btu/h, no supplemental storage tank is installed b) Use a trunk and branch distribution system with all pipes from the water heater to the kitchen being insulated and all pipe with a diameter equal to or greater than ¾ be insulated. c) No recirculation systems installed. New Performance Compliance Options include: a) Point of Use Distribution multiplier now applies to systems with water heaters no more than (5 of ¾ ), (10 of ½ ), or (15 of 3/8 ) of pipe from any point of use are acceptable alternatives. Distances are measured in plan view, allowing for water heaters on either the first or second floor to serve points located on the floor above or below, hence ignoring the direct vertical length of pipe from the water heater. This measure requires HERS verification. b) HERS verified Compact Distribution System credit has been added as a new compliance option credit. The furthest hot water use point from the water heater must be field measured and shown to be within a prescribed distance from the water heater. This measure requires HERS verification. c) Optional HERS verification elements have been added to offer credits for verified quality pipe insulation installation on both recirculating and non-recirculating distribution systems. This measure requires HERS verification. d) Central home run manifold systems located within 5 feet of the water heater will receive a small compliance credit. This measure requires HERS verification. These are intended to give compliance credit for well-designed distribution systems that minimize potential energy losses. Such things as pipe insulation and more efficient distribution design are clearly seen the best options for making a positive impact on the overall Title 24 energy compliance. Multi-family central distribution systems: New Mandatory Requirements: a) Dwelling unit Pipe insulation is now required on all hot water distribution piping greater than ¾ inch diameter, as well as all piping from the water heater to the kitchen. In central multi-family systems all piping in the recirculation loop must be insulated. This requirement applies to the distribution for each dwelling unit. The pipe from the central distribution system to the kitchen or any pipe ¾ inch or greater in the unit distribution system must be insulated. Minimizing energy losses in distribution systems appears to be a main focus in 2013.
New Prescriptive Requirements: a) Demand recirculation controls are basis of performance energy budget for buildings w/ central recirculation systems. b) Water heating recirculation systems are required to be designed w/ two recirculation loops. This measure must be HERS verified to ensure that two sets of recirculation loops are put in place from either the same or separate water heating equipment. Again, these appear to stress the need for well-designed distribution systems that minimize potential energy losses. These new prescriptive rules were added based on studies that found that recirculation pipe heat loss is a major component of energy loss within a central hot water system. New Performance Compliance Options: For systems serving multiple dwelling units with a recirculating pump, the standard distribution system design is based on a central recirculation system with two recirculation loops which are controlled by a demand control technology. Systems designed with other options are allowed but they require compliance verification through performance calculation. More details can be found in the 2013 Residential Compliance Manual, January 2013 edition, Section 5.3.3 While demand recirculation controls are the basis of the performance energy budget, both temperature modulation controls and time clock controls can be used for performance compliance. Using temperature modulation controls will require additional energy efficiency measures to offset higher energy consumption due to higher recirculation loop pipe heat loss than those for demand controls. Using time clock controls will require even more efficiency measures to offset relatively high heat losses from recirculation loops using this control strategy. Continuing on the theme of minimizing potential energy losses. (More details can be found in the 2013 Residential Compliance Manual, January 2014 edition, Section 5.1.2) 2013 Title 24 Rinnai Perspective The use of Rinnai Tankless Water Heaters is a great option to meet the overall Title 24 energy compliance needs. Below is an example (extracted from Designing For Compliance (9/29/11), of how using a Rinnai tankless water heater can assist in achieving the efficiency required by Title 24 when both the space heating and cooling equipment have a negative effect on the calculation. Applying the Title 24 Standards using a.62 EF, our Luxury Series, Non-Condensing RL75 with a.82 EF reflects a 33.9% improvement. The use of this Rinnai tankless water heater gives the overall proposed design an all-important improvement of.4% in the energy usage calculations. For those looking to utilize a recirculation system in their proposed design, the most energy-efficient method is the Demand Recirculation; Manual Control (R-Dman) with only a 1.15 multiplier. The key feature to this on-demand method is the use of a manual switch to activate the recirculation pump. Rinnai Tankless Water Heaters have been used effectively for years with this type of system. Other viable options, like Rinnai s Circ-Logic, which is timer-based, are considered Recirculation; Non-Demand Control (R-ND).
Since ANY type of recirculation is seen as having a negative energy impact, a better question might be How can I achieve less water loss in my hot water distribution system and thereby eliminate the need for recirculation? Potential design solutions may be in Table 5-7 below from the CCR 2013 Residential Compliance Manual. Compact Design (CHWDS-H) which garners a potential 30% savings (.7 multiplier) or better Pipe Insulation (PIC-H) with a 20% potential savings (.8 multiplier), cannot only have a major impact on Title 24 calculations, but may also eliminate the need for recirculation totally. The versatility of a tankless water heater which, allows one to easily locate closer to fixtures, is ideally suited for Compact Design, saving you additional project cost on equipment, materials and labor. The installation of a tankless water heater is the best decision when thinking of the overall implications of Title 24 on the construction and energy usage in buildings, along with the new requirements that mandate the builder to implement measures to make the dwelling unit High Efficiency Ready. We hope energy conversation AND water conservation are at the top of everyone s list when designing, specifying and installing hot water distribution systems and equipment, and Rinnai has current solutions that support both these important initiatives.