Page 509 - 2018_IRC

ENERGY EFFICIENCY

by an accredited, independent laboratory and listed and manufacturer with a heating temperature setpoint of not
labeled by the manufacturer. greater than 70°F (21°C) and a cooling temperature setpoint
Exception: Site-built windows, skylights and doors. of not less than 78°F (26°C).
N1102.4.4 (R402.4.4) Rooms containing fuel-burning N1103.1.2 (R403.1.2) Heat pump supplementary heat
appliances. In Climate Zones 3 through 8, where open (Mandatory). Heat pumps having supplementary electric-
combustion air ducts provide combustion air to open com- resistance heat shall have controls that, except during
bustion fuel-burning appliances, the appliances and com- defrost, prevent supplemental heat operation when the
bustion air opening shall be located outside the building heat pump compressor can meet the heating load.
thermal envelope or enclosed in a room that is isolated N1103.2 (R403.2) Hot water boiler outdoor temperature
from inside the thermal envelope. Such rooms shall be setback. Hot water boilers that supply heat to the building
sealed and insulated in accordance with the envelope through one- or two-pipe heating systems shall have an out-
requirements of Table N1102.1.2, where the walls, floors door setback control that decreases the boiler water tempera-
and ceilings shall meet a minimum of the basement wall ture based on the outdoor temperature.
R-value requirement. The door into the room shall be fully
gasketed and any water lines and ducts in the room insu- N1103.3 (R403.3) Ducts. Ducts and air handlers shall be
lated in accordance with Section N1103. The combustion installed in accordance with Sections N1103.3.1 through
N1103.3.8.
air duct shall be insulated where it passes through condi-
tioned space to an R-value of not less than R-8. N1103.3.1 (R403.3.1) Insulation (Prescriptive). Supply
and return ducts in attics shall be insulated to an R-value
Exceptions:
of not less than R-8 for ducts 3 inches (76 mm) in diameter
1. Direct vent appliances with both intake and and larger and not less than R-6 for ducts smaller than 3
exhaust pipes installed continuous to the outside. inches (76 mm) in diameter. Supply and return ducts in
other portions of the building shall be insulated to not less
2. Fireplaces and stoves complying with Sections
N1102.4.2 and R1006. than R-6 for ducts 3 inches (76 mm) in diameter and to not
less than R-4.2 for ducts smaller than 3 inches (76.2 mm)
N1102.4.5 (R402.4.5) Recessed lighting. Recessed lumi- in diameter.
naires installed in the building thermal envelope shall be Exception: Ducts or portions thereof located com-
sealed to limit air leakage between conditioned and uncon-
ditioned spaces. Recessed luminaires shall be IC-rated and pletely inside the building thermal envelope.
labeled as having an air leakage rate of not greater than 2.0 N1103.3.2 (R403.3.2) Sealing (Mandatory). Ducts, air
cfm (0.944 L/s) when tested in accordance with ASTM handlers and filter boxes shall be sealed. Joints and seams
E283 at a pressure differential of 1.57 psf (75 Pa). Recessed shall comply with Section M1601.4.1.
luminaires shall be sealed with a gasket or caulked between N1103.3.2.1 (R403.3.2.1) Sealed air handler. Air han-
the housing and the interior wall or ceiling covering.
dlers shall have a manufacturer’s designation for an air
N1102.5 (R402.5) Maximum fenestration U-factor and leakage of not greater than 2 percent of the design air-
SHGC (Mandatory). The area-weighted average maximum flow rate when tested in accordance with ASHRAE 193.
fenestration U-factor permitted using tradeoffs from Section N1103.3.3 (R403.3.3) Duct testing (Mandatory). Ducts
N1102.1.5 or N1105 shall be 0.48 in Climate Zones 4 and 5 shall be pressure tested to determine air leakage by one of
and 0.40 in Climate Zones 6 through 8 for vertical fenestra- the following methods:
tion, and 0.75 in Climate Zones 4 through 8 for skylights. The
area-weighted average maximum fenestration SHGC permit- 1. Rough-in test: Total leakage shall be measured with a
ted using tradeoffs from Section N1105 in Climate Zones 1 pressure differential of 0.1 inch w.g. (25 Pa) across
through 3 shall be 0.50. the system, including the manufacturer’s air handler
enclosure if installed at the time of the test. Registers
shall be taped or otherwise sealed during the test.
SECTION N1103 (R403)
SYSTEMS 2. Postconstruction test: Total leakage shall be mea-
sured with a pressure differential of 0.1 inch w.g.
N1103.1 (R403.1) Controls (Mandatory). Not less than one (25 Pa) across the entire system, including the man-
thermostat shall be provided for each separate heating and ufacturer’s air handler enclosure. Registers shall be
cooling system. taped or otherwise sealed during the test.
N1103.1.1 (R403.1.1) Programmable thermostat. The Exceptions:
thermostat controlling the primary heating or cooling sys-
tem of the dwelling unit shall be capable of controlling the 1. A duct air-leakage test shall not be required
heating and cooling system on a daily schedule to maintain where the ducts and air handlers are located
different temperature set points at different times of the day. entirely within the building thermal envelope.
This thermostat shall include the capability to set back or 2. A duct air-leakage test shall not be required for
temporarily operate the system to maintain zone tempera- ducts serving heat or energy recovery ventilators
tures of not less than 55°F (13°C) to not greater than 85°F that are not integrated with ducts serving heating
(29°C). The thermostat shall be programmed initially by the or cooling systems.

484 2018 INTERNATIONAL RESIDENTIAL CODE ®
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