Wisconsin Administrative Code › Department of Safety and Professional Services › SPS 301-399 - Safety, Buildings, and Environment › SPS 320-325 - Uniform Dwelling Code › Chapter SPS 322 - Energy Conservation › Subchapter VI - Simulated Performance Alternative › Section SPS 322.53 - Calculation procedure

Current through June 24, 2024
(1) GENERAL. Except as specifically allowed
					 under this section, the standard reference design and proposed design shall be
					 configured and analyzed using identical methods and techniques.
(2) REFERENCE AND PROPOSED DESIGNS. The
					 standard reference design and proposed design shall be configured and analyzed
					 as specified by Table 322.53-1. Table 322.53-1 shall include by reference all
					 notes contained in Table 322.31-1.
(3) CALCULATION SOFTWARE TOOLS. Calculation
					 procedures used to comply with this section shall be capable of calculating the
					 annual energy consumption of all building elements that differ between the
					 standard reference design and the proposed design and shall include the
					 following capabilities:
(a) Computer
					 generation of the standard reference design using only the input for the
					 proposed design. The calculation procedure may not allow the user to directly
					 modify the building component characteristics of the standard reference
					 design.
(b) Calculation of
					 whole-building sizing as a single zone for the heating and cooling equipment in
					 the standard reference design residence in accordance with s.
					 SPS
					 322.40(3).
(c) Calculations that account for the effects
					 of indoor and outdoor temperatures and part-load ratios on the performance of
					 heating, ventilating and air conditioning equipment based on climate and
					 equipment sizing.
(d) Printed code
					 official inspection checklist listing each of the proposed design component
					 characteristics from Table 322.53-1 determined by the analysis to provide
					 compliance, along with their respective performance ratings.
Building Component
Standard Reference Design
Proposed Design
Above-grade walls
Type: mass wall if proposed wall is mass;
									 otherwise wood frame
As proposed
Gross area: same as proposed
As proposed
U-Factor: from Table 322.31-2
As proposed
Solar absorptance = 0.75
As proposed
Emittance = 0.90
As proposed
Basement and crawlspace walls
Type: same as proposed
As proposed
Gross area: same as proposed
As proposed
U-Factor: from Table 322.31-2 with insulation
									 layer on interior side of walls
As proposed
Above-grade floors
Type: wood frame
As proposed
Gross area: same as proposed
As proposed
U-Factor: from Table 322.31-2
As proposed
Ceilings
Type: wood frame
As proposed
Gross area: same as proposed
As proposed
U-Factor: from Table 322.31-2
As proposed
Roofs
Type: composition shingle on wood
									 sheathing
As proposed
Gross area: same as proposed
As proposed
Solar absorptance = 0.75
As proposed
Emittance = 0.90
As proposed
Attics
Type: vented with aperture = 1
									 ft2 per 300 ft2 ceiling
									 area
As proposed
Foundations
Type: same as proposed
As proposed
Doors
Area: 40 ft2
As proposed
Orientation: North
U-Factor: same as fenestration from
									 Table
As proposed
322.31-2
As proposed
Glazinga
Total areab= (a) The
									 proposed glazing area; where the proposed glazing area is less than 18% of the
									 conditioned floor area
As proposed
(b) 18% of the conditioned floor area; where
									 the proposed glazing area is 18% or more of the conditioned floor area
									 Orientation: equally distributed to four cardinal
compass orientations
As proposed
U-Factor: from Table 322.31-2
As proposed
SHGC = 0.40 Interior shade fraction: Summer
									 (all hours when cooling is required) =
0.70 Winter (all hours when heating is
									 required) = 0.85
As proposed Same as standard reference
									 designc
External shading: none
As proposed
Skylights
U-Factor: from Table 322.31-2
As proposed
Thermally isolated sunrooms
None
As proposed
Air exchange rate
Specific Leakage Area
									 (SLA)d = 0.00036 assuming no energy recovery
For residences that are not tested, the same as
									 the standard reference design;
For residences without mechanical ventilation
									 that are tested in accordance with ASHRAE 119, Section 5.1, the measured air
									 exchange ratee but not less than 0.35 ACH;
For residences with mechanical ventilation that
									 are tested in accordance with ASHRAE 119, Section 5.1, the measured air
									 exchange ratee combined with the mechanical
									 ventilation ratef, which may not be less than 0.01 X
									 CFA + 7.5 X (N br + 1) where:
CFA = conditioned floor area
N br = number of bedrooms
Mechanical ventilation
None, except where mechanical ventilation
									 is
specified by the proposed design, in which
									 case: Annual vent fan energy use: kWh/yr = 0.03942 X CFA + 29.565 X (N br + 1)
									 where: CFA = conditioned floor area N br = number of bedrooms
As proposed
Internal gains
IGain = 17,900 + 23.8 x CFA + 4,104 X N br
									 (Btu/day per dwelling unit)
Same as standard reference design
Internal mass
An internal mass for furniture and contents of
									 8 pounds per square foot of floor area
Same as standard reference design, plus any
									 additional mass specifically designed as a thermal storage
									 elementg but not integral to the building envelope
									 or structure
Structural mass
For masonry floor slabs, 80% of floor area
									 covered by R-2 carpet and pad, and 20% of floor directly exposed to room
									 air;
As proposed
For masonry basement walls, as proposed, but
									 with insulation required by Table 322.31-2 located on the interior side of the
									 walls;
As proposed
For other walls, for ceilings, floors, and
									 interior walls, wood frame construction
As proposed
Heating systems 
									 h,i
Fuel type: same as proposed design
									 efficiencies:
As proposed
Electric: air-source heat pump with prevailing
									 federal minimum efficiency;
As proposed
Nonelectric furnaces: natural gas furnace
									 in
accordance with Table 322.31-3;
As proposed
Nonelectric boilers: natural gas boiler in
									 accordance with Table 322.31-3;
As proposed
Capacity: sized in accordance with section
									 SPS
									 322.40(3)
As proposed
Cooling systems 
									 h,j
Fuel type: electric
As proposed
Efficiency: in accordance with prevailing
									 federal minimum standards
As proposed
Capacity: sized in accordance with section
									 SPS
									 322.40(3)
As proposed
Service Water Heating 
									 h,k
Fuel type: same as proposed design
As proposed
Efficiency: in accordance with prevailing
									 federal minimum standards
As proposed
Use: gal/day = 30 + 10 X N br
Same as standard reference
Tank temperature: 120°F
Same as standard reference
Thermal distribution systems
A thermal distribution system efficiency (DSE)
									 of 0.80 shall be applied to both the heating and cooling system
									 efficiencies
Same as standard reference design, except as
									 specified by Table 322.53-2
Thermostat
Type: manual, cooling temperature set point =
									 78°F; heating temperature set point = 68°F
Same as standard reference design
a Glazing shall be defined as
						sunlight-transmitting fenestration, including the area of sash, curbing or
						other framing elements, that enclose conditioned space. Glazing includes the
						area of sunlight-transmitting fenestration assemblies in walls bounding
						conditioned basements. For doors where the sunlight-transmitting opening is
						less than 50% of the door area, the glazing area is the sunlight transmitting
						opening area. For all other doors, the glazing area is the rough frame opening
						area for the door including the door and the frame.
b For residences with
						conditioned basements, R-2 and R-4 residences and townhouses, the following
						formula shall be used to determine glazing area: AF = As X FA X F where:
1. AF = Total glazing area.
2. As = Standard reference design total
					 glazing area.
3. FA = (Above-grade
					 thermal boundary gross wall area)/(above-grade boundary wall area + 0.5 x
					 below-grade boundary wall area).
4.
					 F = (Above-grade thermal boundary wall area)/(above-grade thermal boundary wall
					 area + common wall area) or 0.56, whichever is greater.
And where:
5. Thermal boundary wall is any wall that
					 separates conditioned space from unconditioned space or ambient
					 conditions.
6. Above-grade thermal
					 boundary wall is any thermal boundary wall component not in contact with
					 soil.
7. Below-grade boundary wall
					 is any thermal boundary wall in soil contact.
8. Common wall area is the area of walls
					 shared with an adjoining dwelling unit.
c For fenestrations facing
						within 15 degrees of true south that are directly coupled to thermal storage
						mass, the winter interior shade fraction may be increased to 0.95 in the
						proposed design.
d Where Leakage Area (L) is
						defined in accordance with Section 5.1 of ASHRAE 119 and where: SLA = L/CFA
						where L and CFA are in the same units.
e Tested envelope leakage
						shall be determined and documented by an independent party approved by the code
						official. Hourly calculations as specified in the 2005 ASHRAE Handbook of
						Fundamentals, Chapter 27, page 27.21, Equation 40, Sherman-Grimsrud model, or
						the equivalent shall be used to determine the energy loads resulting from
						infiltration.
f The combined air exchange
						rate for infiltration and mechanical ventilation shall be determined in
						accordance with Equation 43 of 2005 ASHRAE Handbook of Fundamentals page 27.23
						and the "Whole-house Ventilation" provisions of 2005 ASHRAE Handbook of
						Fundamentals, page 27.18 for intermittent mechanical ventilation.
g Thermal Storage Element
						means a component not part of the floors, walls or ceilings that is part of a
						passive solar system, and that provides thermal storage such as enclosed water
						columns, rock beds, or phase-change containers. A thermal storage element must
						be in the same room as fenestration that faces within 15 degrees of true south,
						or must be connected to a room with pipes or ducts that allow the element to be
						actively charged.
h For a proposed design with
						multiple heating, cooling or water heating systems using different fuel types,
						the applicable standard reference design system capacities and fuel types shall
						be weighted in accordance with their respective loads as calculated by accepted
						engineering practice for each equipment and fuel type present.
i For a proposed design
						without a proposed heating system, a heating system of 90% annual fuel
						utilization shall be assumed for both the standard reference design and
						proposed design. For electric heating systems, the prevailing federal minimum
						efficiency air-source heat pump shall be used for the standard reference
						design.
j For a proposed design home
						without a proposed cooling system, an electric air conditioner with the
						prevailing federal minimum efficiency shall be assumed for both the standard
						reference design and the proposed design.
k For a proposed design with a
						non-storage-type water heater, a 40-gallon storage-type water heater with the
						prevailing federal minimum energy factor for the same fuel as the predominant
						heating fuel type shall be assumed. For the case of a proposed design without a
						proposed water heater, a 40-gallon storage-type water heater with the
						prevailing federal minimum efficiency for the same fuel as the predominant
						heating fuel type shall be assumed for both the proposed design and standard
						reference design.
TABLE 322.53-2