3910 RIVERFRONT BLVD BLDG A 2025-08-15

INSTRUCTIONS FOR HEATING EQUIPMENT SIZING FORM Building Code Section 1204.1 and Residential Code Section R303.8 establish a minimum required heating output,and Energy Code Sections 503.2.2 and 1422/1431.2 specify a maximum allowed heating equipment output. General Information: This form is recommended for sizing the heating systems for all residential buildings. It may be used for commercial buildings where appropriate. This form,or acceptable alternate calculations,must be completed for each dwelling unit. A separate copy shall be attached to each set of drawings submitted with the building permit application and over-the-counter(OTC)permit application. If new or enlarged electric service is to be installed in an existing building,you may be subject to additional Seattle City Light requirements. For further information,contact Seattle City Light at 206-615-0600 if the project is north of Denny Way or 206-386-4200 if the project is south of Denny Way. Detailed Instructions(step numbers match the numbers shown on the front of the form): -For existing buildings,complete for each dwelling unit as proposed after remodeling. If space heating equipment is simply being replaced,complete for the dwelling unit as existing. -For new construction,complete for each dwelling unit as proposed. Values in bold are Prescriptive requirements for single-familylduplex. (1)On the line with the appropriate description: -For components A-E,enter the square footage for windows,skylights,sliding glass doors,opaque doors,opaque roof/ceiling(minus skylights), opaque wall(minus windows and doors),floor over unheated space. -For component F,enter the linear feet of perimeter for slab-on-grade floor(less than two feet below grade),not the square footage area of the slab. -For component G,enter the linear feet of perimeter for basement floor(more than two feet below grade). Do not enter if the basement is unheated. -For component H,enter the volume in cubic feet of the interior heated space based on when the dwelling unit or portion thereof was or will be built. For glazing and doors,where U-factors different from those specified are used,enter those U-factors in the blanks provided for that category.For other components,where R-values different from those specified are used,enter that value and the corresponding U-factor or F-factor in the blanks provided in that category.For all new entries,multiply the U-factor or F-factor by the 46°F.design temperature difference(70°F.-24°F.)to obtain the corresponding heat loss factor and enter that value in the Heat Loss Factor column. (2)Multiply the heat loss factor by component square feet(sq.ft),linear feet(lin.ft.)or cubic feet(cu.ft),as appropriate to obtain the component heat loss. (Automated in the electronic version of this form.] (3)Add all entries to obtain the total which is the Design Heating Load(DHL). (Automated in the electronic version of this form.] (4)Enter the heated floor area of the dwelling unit,then divide the DHL by the heated floor area to obtain the load on a square foot basis. (Note that typical values for new construction are 8 Btuh/SF or 2.5 Watts/SF.) (5)To determine the allowable heating equipment output range: -Multiply Design Heating Load(in either Btuh or Watts)by 1.0 to obtain minimum size required by the Building Code(Section 303.8) -Multiply Design Heating Load(in either Btuh or Watts)by 1.5 to obtain maximum allowed by the Energy Code(Section 503.2.2/1422/1431.2) (Note that,for nonresidential buildings,there are no minimum Building Code requirements and the maximum Energy Code allowance is 150%of the DHL.) (Automated in the electronic version of this form.] (6)Enter proposed equipment size(output)and efficiency. The proposed equipment output must be within the minimum and maximum allowed. Note that Energy Code Section 503.2.2, -Exception 2 exempts natural gas-and oil-fired space heating equipment whose total rated space heating output in any one dwelling unit is 40,000 Btulh or less from the sizing limit. -Exception 4 exempts electric resistance heaters under 2 kW from the sizing limit. (Note that there are no exceptions from the 150%sizing limit for high-efficiency equipment or for any other systems,such as heat pumps.) Seattle DPD,2009sec-HeatingEquipmentSizingForm.xls,January 2011 download from the Seattle Energy Code website residential forms page at http://www.seattle.gov/dpd/energylformsres.htm •