## 4.2 Heating Equipment

This section addresses the requirements for heating equipment, including furnaces, boilers, heat pumps, and electric resistance equipment.

### 4.2.1 Mandatory Measures for Heating Equipment

#### 4.2.1.1 Equipment Efficiency

§110.1 and §110.2(a). Appliance Efficiency Regulations

The efficiency of most heating equipment is regulated by NAECA (the federal appliance standard) and the California Appliance Efficiency Regulations. These regulations are not contained in the Energy Standards but are published separately. These regulations are referenced in §110.1|topic=SECTION 110.1 – MANDATORY REQUIREMENTS FOR APPLIANCES. The Appliance Efficiency Regulations include definitions for all types of equipment and are regularly updated, which may change the minimum efficiencies of most equipment.

Note: The Appliance Efficiency Regulations that are in effect when the building permit is applied for will determine the minimum efficiency of the appliances identified in the compliance documentation.

The energy efficiency of other equipment is regulated by §110.2(a)|topic=(a) Efficiency.. Also, see the Nonresidential Compliance Manual for more information on larger equipment.

A. Gas and Oil-Fired Furnaces

The Appliance Efficiency Regulations (Title 20) require gas and oil-fired central furnaces with outputs less than 225,000 Btu/hr to be rated according to the associated Annual Fuel Utilization Efficiency (AFUE). Gas and oil-fired central furnaces with outputs greater than or equal to 225,000 Btu/hr are rated according to the respective thermal (or steady-state) efficiency. Refer to Table 4-1 for the applicable efficiency requirements.

#### Table 4-1 – : Minimum Efficiency for Gas and Oil-Fired Central Furnaces

Appliance | Minimum Efficiency (%)
Rated Input (Btu/hr) | AFUE | Thermal Efficiency
Weatherized gas central furnaces with single phase electrical supply | < 225,000 | 81 | —
Non-weatherized gas central furnaces with single phase electrical supply | < 225,000 | 80 | —
Weatherized oil central furnaces with single phase electrical supply | < 225,000 | 78 | —
Non-weatherized oil central furnaces with single phase electrical supply | < 225,000 | 83 | —
Gas central furnaces | ≥ 225,000 | — | 80
Oil central furnaces | ≥ 225,000 | — | 81

Source: California Appliance Efficiency Regulations Title-20 - Table E-4 and E-6

Noncentral gas furnaces and space heaters shall be certified to have AFUE values greater than or equal to those 'listed Table 4-2.

#### Table 4-2 – : Minimum Heating Efficiency for Nonducted,
Noncentral Gas-Fired Heating Equipment

Type | Capacity | AFUE
Wall Furnace (fan type) | ≤ 42,000 Btu/h | 75%
> 42,000 Btu/h | 76%
Wall Furnace (gravity type) | ≤ 27,000 Btu/h | 65%
> 27,000 Btu/h and ≤ 46,000 Btu/h | 66%
> 46,000 Btu/h | 67%
≤ 37,000 Btu/h | 57%
> 37,000 Btu/h | 58%
≤20,000 Btu/h | 61%
> 20,000 Btu/h and ≤ 27,000 Btu/h | 66%
Floor Furnace | > 27,000 Btu/h and ≤ 46,000 Btu/h | 67%
> 46,000 Btu/h | 68%
Room Heater | ≤ 42,000 Btu/h | 75%
> 42,000 Btu/h | 76%
≤ 27,000 Btu/h | 65%
> 27,000 Btu/h and ≤ 46,000 Btu/h | 66%
> 46,000 Btu/h | 67%

Source: California Appliance Efficiency Regulations Title-20 - Table E-2

A. Heat Pumps and Electric Heating

Heat pumps shall be certified to have a HSPF or COP equal to or better than those 'listed in Table 4-3.

There are no minimum appliance efficiency standards for electric-resistance or electric-radiant heating systems.

A. Gas- and Oil-Fired Central Boilers and Electric Boilers

Gas- and oil-fired central boilers shall be certified to have and AFUE or Combustion Efficiency equal to or better than those listed in

#### Table 4-3 –: Minimum Heating Efficiency for Heat Pumps

Equipment Type | Appliance Efficiency Reg. Reference | Configuration/Size | Minimum Heating Efficiency
Packaged terminal heat pumps (heating mode) | Table 110.2 E | Newly constructed or newly conditioned buildings or additions | 3.7-(0.052 x Cap1/1000) = COP
Packaged terminal heat pumps (heating mode) | Table 110.2 E | Replacements | 2.9-(0.026 x Cap1/1000) = COP
Single- phase air source heat pumps (NAECA) | Table C-2 | < 65,000 Btu/h cooling | Packaged 8.0 HSPF Split 8.2 HSPF
Space constrained < 65,000 Btu/h cooling capacity | Packaged 7.4 HSPF Split 7.4 HSPF
Small -duct high -velocity < 65,000 Btu/h cooling capacity | 7.7 HSPF
Three-phase air source heat pumps | Table C-3 | < 65,000 Btu/h | Packaged 7.47 HSPF Split 7.47 HSPF
≥ 65,000 and <135,000 | 3.3 COP
≥ 135,000 and <240,000 | 3.2 COP
≥ 240,000 and <760,000 | 3.2 COP
Water-source heat pumps | Table C-4 | 65,000 and< 135,000 Btu/h | 4.2 COP
≥ 135,000 Btu/h, < 240,000 Btu/h | 2.9 COP
Single package vertical heat pumps | Table C-5 | < 65,000 single -phase | 3.0 COP
< 65,000 3-Phase | 3.0 COP
≥ 65,000 and < 135,000 | 3.0 COP
≥ 135,000 and < 240,000 | 2.9 COP
1. Cap = Cooling Capacity

Source: California Appliance Efficiency Regulation Title 20 and Energy Efficiency Standards

#### Table 4-4 –: Minimum Efficiency for Gas and Oil Fired Central Boilers

Appliance | Rated Input (Btu/hr) | Minimum Efficiency (%)
Gas steam boilers with single-phase electrical supply | < 300,000 | 80 ¹ | AFUE
Gas hot water boilers with single-phase electrical supply | < 300,000 | 82 ¹,² | AFUE
Oil steam boilers with single-phase electrical supply | < 300,000 | 82 | AFUE
Oil hot water boilers with single-phase electrical supply | < 300,000 | 84 ² | AFUE
Electric steam residential boilers | < 300,000 | — | —
Electric hot water residential boilers | < 300,000 | — | —
All other boilers with single-phase electrical supply | < 300,000 | — | —
Steam boilers; gas-fired, except natural draft; | ≥ 300,000 | Thermal Efficiency | Combustion Efficiency
79 | 80
Steam boilers; gas-fired, natural draft | ≥ 300,000 | 77 | 80
Steam boilers; oil-fired | ≥ 300,000 | 81 | 83
¹ No constant burning pilot light design standard. ² Automatic means for adjusting temperature design standard.

Source: California Appliance Efficiency Regulations Title-20 Table E-3 and E-4

#### 4.2.1.2 Heating System Controls

§150.0(i), 110.2(b), Exceptions to §110.2(b), 110.2(c), Exception to 110.2(c)

All unitary heating systems, including heat pumps, must be controlled by a setback thermostat. These thermostats must be capable of allowing the occupant to program the temperature set points for at least four different periods in 24 hours. For example, the setback thermostat could be programmed at specific temperature starting at 6:30 am, 9:00 am, 4:30 pm and 9:00 pm, thus allowing for four periods within 24 hours.

If the heating system is integrated into a central energy management control system (EMCS), then that system does not need to comply with the setback requirements. Additionally, all gravity gas wall heaters, floor heaters, room heaters and fireplaces, decorative gas appliances, wood stoves and non-central electric heaters do not need to be controlled by a setback thermostat.

Any heat pump with supplementary electric resistance heating must have controls that have two capabilities to limit the electric resistance heating. The first is to set the cut-on and cut-off temperatures for compression and supplementary heating at different levels.

For example, if the heat pump begins heating when the inside temperature reaches 68°F, the electric resistance heating is set to come on if the temperature gets below 65°F; and there is an opposite off mode such that if the heat pump shuts off when the temperature reaches 72°F, the back-up heating shuts off at 68°F.

The second control capability prevents the supplementary electric resistance heater from operating when the heat pump alone can meet the heating load, except during defrost. There is a limited exception to this second function for “smart thermostats” that provide the following: intelligent recovery, staging, ramping, or another control mechanism that prevents the unnecessary operation of supplementary electric resistance heating when the heat pump alone can meet the heating load.

To meet the thermostat requirements, a thermostat for a heat pump must be a “smart thermostat” that minimizes the use of supplementary heating during startup and recovery from setbacks.

Note: Room air conditioner heat pumps are not required to comply with the thermostat requirements.

#### 4.2.1.3 Equipment Sizing

§150.0(h)1and 2

The Energy Standards do not set limits on the sizing of heating equipment, but they do require that heating loads be calculated for new heating systems. Oversized equipment typically operates less efficiently and can create comfort problems due to excessive cycling and high airflow.

Acceptable load calculation procedures include methods described in the following publications:

The ASHRAE Handbook – Equipment,

The ASHRAE Handbook – Applications,

The ASHRAE Handbook – Fundamentals,

The SMACNA Residential Comfort System Installation 'Manual, or

ACCA 'Manual J

The Energy Standards require that the outdoor design conditions for load calculations be selected from Reference Joint Appendix JA2, and that the indoor design temperature for heating load calculations be 68°F.

The outdoor design temperature must be no lower than the “heating winter median of extremes” as 'listed in the Reference Joint Appendix JA2.

If the actual city location for a project is not included in the Reference Joint Appendix JA2, or if the data given for a particular city does not match the conditions at the actual site as well as that given for another nearby city, consult the local building department for guidance.

The load calculations must be submitted with the compliance documentation when requested by the building department.

The load calculations may be prepared by 1) a mechanical engineer, 2) the mechanical contractor who is installing the equipment or 3) someone who is qualified to do so in the State of California according to Division 3 of the Business and Professions Code.

Note: The Business and Professions Code does not prohibit an unlicensed person from preparing plans, drawings, or specifications for single-family dwelling units of wood-frame construction not more than two stories and basement in height, or for certain buildings containing no more than four dwelling units of wood-frame construction not more than two stories and basement in height. However, licensure is required for apartment or condominium complexes.

#### 4.2.1.4 Furnace Temperature Rise

§150.0(h)4

High temperature rise in a furnace is an indicator of low airflow and/or over specification firing rate. High temperature rise causes low efficiency and may potentially damage the furnace. Central forced-air heating furnace installations must be configured to operate at or below the furnace manufacturer's maximum inlet-to-outlet temperature rise specification.

#### 4.2.1.5 Standby Losses and Pilot Lights

§110.5 and §110.2(d)

Fan-type central furnaces may not have a continuously burning pilot light. This requirement does not apply to wall furnaces, floor furnaces or any gravity type furnace. Household cooking appliances also must not have a continuously burning pilot light, except for those without an electrical supply voltage connection and in which each pilot consumes less than 150 Btu/hr.

Larger gas-fired and oil-fired forced air furnaces with input ratings equal to or greater than 225,000 Btu/h (which is bigger than a typical residential furnace) must also have an intermittent ignition device (IID) and either power venting or a flue damper.

A vent damper is an acceptable alternative to a flue damper for furnaces where combustion air is drawn from the conditioned space. All furnaces with input ratings ≥ 225,000 Btu/h, including electric furnaces, that are not within the conditioned space must have jacket losses not exceeding 0.75 percent of the input rating.

#### 4.2.1.6 Pipe Insulation

§150.0(j)2C, §150.0(j)3, §120.3

The piping for heat pumps and for both steam and hydronic heating systems shall meet the insulation requirements provided below in Table 4-5 when the insulation is located outside conditioned space, it requires protection from damage caused by environmental conditions. The insulation must be rated for outdoor use or covered with a material that can withstand the outdoor conditions. Examples of these types of coverings are aluminum, sheet metal, painted canvas, plastic cover, or, if the insulation is cellular foam, a coating that is water-retardant and shields from solar radiation. Moreover, the insulation used for the refrigerant suction line of a heat pump must be Class I or Class II vapor retardant. If the insulation is not Class I or Class II, then the insulation must be installed at the required thickness that would qualify it as a Class I or Class II vapor-retarder.

#### Table 4-5 -: Insulation Requirements for Heating System Piping

Fluid Temperature Range (oF) | Conductivity Range (in Btu-inch per hour per square foot per (oF) | Insulation Mean Rating Temperature (oF) | Nominal Pipe Diameter (in inches)
1 and less | 1 to <1.5 | 1.5 to <4 | 4 to <8 | 8 and larger
Insulation Thickness Required (in inches)
Space Heating, Hot Water Systems (Steam, Steam Condensate and Hot Water), Service Water Heating Systems
Above 350 | 0.32-0.34 | 250 | 4.5 | 5.0 | 5.0 | 5.0 | 5.0
251-350 | 0.29-0.31 | 200 | 3.0 | 4.0 | 4.5 | 4.5 | 4.5
201-250 | 0.27-0.30 | 150 | 2.5 | 2.5 | 2.5 | 3.0 | 3.0
141-200 | 0.25-0.29 | 125 | 1.5 | 1.5 | 2.0 | 2.0 | 2.0
105-140 | 0.22-0.28 | 100 | 1.0 | 1.5 | 1.5 | 1.5 | 1.5
Heat Pump Suction Line
40-60 | 0.21-0.27 | 75 | 0.75 | 0.75 | 1.0 | 1.0 | 1.0
Below 40 | 0.20-0.26 | 50 | 1.0 | 1.5 | 1.5 | 1.5 | 1.5

From Table 120.3 A of the Building Energy Efficiency Standards

### 4.2.2 Prescriptive Requirements for Heating Equipment

§150.1(c)6Heating System Type

Prescriptive Component Package A requires the installation of a gas heating system or heat pump that meet the required minimum energy efficiency (See Table 4-1 through Table 4-4|topic=Table 4-4 –\: Minimum Efficiency for Gas and Oil Fired Central Boilers).

Supplemental heating systems are allowed prescriptively and the designer may elect to provide supplemental heating to a space such as a bathroom. In this instance, the supplemental heating system must be installed in a space that is served by the primary heating system and must have a thermal capacity of less than 2 kilowatts (kW) or 7,000 Btu/hr while being controlled by a time-limiting device not exceeding 30 minutes. Electric resistance and electric radiant heating installation are allowed as the primary heating system only when using the performance compliance method when using the prescriptive compliance approach, no additional credit is given for selecting equipment that is higher than what is required by the prescriptive component package.

### 4.2.3 Compliance Options for Heating Equipment

There is one option for receiving compliance credit related to the heating system. This credit is available through the performance compliance method.

#### 4.2.3.1 High Efficiency Heating

Heating system efficiencies are explained in Section 4.2.1.1. The minimum efficiency is required according to the prescriptive package. When the performance compliance approach is used, additional compliance credit may be available when higher efficiency heating equipment, such as a high-efficiency furnace or heat pump, is modeled. For example, selecting a nonweatherized furnace with an AFUE higher than 81 will result in a compliance credit, which can be used to offset other building features that do not meet the prescriptive requirements. However, all mandatory requirements must be complied with.