Home Heating Analysis Worksheet Appendix C Introduction This home energy audit will guide you in calculating the heat loss of your residence. This audit includes heat gains from various sources; Item H (on the summary page) will allow you to compare the energy use of your home with that of others. You will also be able to compare costs of heating your home with various fuels by using Section II and Item F. Analysis of your findings will indicate which features in your house are wasting the greatest amounts of energy. An easy-to-print PDF version of this worksheet is available for download on the companion Web site for this book. Directions Page 1 A. Fill in each of the blanks in Section I. B. From your utility companies, find out the local cost per unit measure for each of the fuel sources in Section II. C. Calculate the cost per MBtu delivered to the living space. D. Make a sketch of your home, including the area of each type of exterior surface. Page 2 A. You may want to make several copies of page 2 (room data page), allowing calculations of heat losses for up to 12 rooms. B. For each room of your home with exterior heat-dissipating surfaces, fill in the data requested: 1. Provide the name of the room. 2. Provide the surface areas of all heat-dissipating surfaces. C-1 90831_appendixC.indd C-1
C-2 Appendix C 3. Referring to the table of heat-loss factors at the end of this appendix on pages C-8 C-10, note the surface type at 1 and the corresponding factor at 2 for each surface. 4. Multiply the surface area by the factor 2 to determine the Btu/h loss. 5. Add the column of Btu/h losses for each room to determine the total room loss. Page 3 On Summary page C-6 A. 1. Add the Btu/h losses of all windows from all rooms and record under Sum of Rows. 2. Add the Btu/h losses of each other feature and record under Sum of Rows. 3. Calculate infiltration losses. 1. Select the K factor from Item 7 in the table of heat-loss factors. 2. Transfer the volume of heated space from page 1. 3. Multiply 0.018 3 65 3 K 3 volume of heated space. 4. Add all losses (Sum of Rows) to determine the total peak hourly loss (Btu/h). 5. Calculate the percent total heat loss for each surface type (total loss of each type 4 total peak hourly loss 3 100). B. Calculate the losses as a result of heat transfer from the central heating system. C. Calculate the heat gains. D. Calculate the peak net heat loss. E. Calculate the seasonal heating needs. F. Determine the total heating cost by multiplying Item E by the cost per MBtu for the fuel used to heat your home (see Section II on page 1). G. Compare your calculated heating season cost with your actual heating season cost. H. Calculate the Btu/degree-day/ft 2 and compare with the heating requirements of other homes. I. If there is a discrepancy between the calculated and actual total heating season costs (Items F and G), try to explain why. 90831_appendixC.indd C-2
Appendix C C-3 Name: Page 1 Home Heating Analysis 1 General Information: 1. All dimensions should be measured and not estimated. 2. The surface heat loss is equal to the factor you choose for that surface multiplied by the surface area. 3. Selection of a living unit with a self-contained heating system is preferred. 4. Prepare a drawing illustrating floor plan(s): room names, dimensions and areas; locations and sizes of exterior doors and windows. Calculate total area by floor level. Show wall thickness. Indicate north compass direction. 5. Round all values to the nearest tenth. I. Location of building: (city); (state) Latitude: (to nearest whole degree) Degree-days: Type of structure: house number of stories apartment/duplex mobile home Type of construction (Example: standard height concrete block foundation; wood frame with 2 3 4 studs, 3½ fiberglass insulation, cedar shiplap siding, 12 fiberglass ceiling insulation, ceiling heights: 8 1st floor, 7 6 2nd floor) Total amount of heated space: ft 2 (floor area); ft 3 (volume) Type of heat source(s): (oil, natural gas, electric, LP, wood, etc.) Type of heating system: (forced hot air, baseboard hot water, electric baseboard, radiant, etc.) Rating of heating system: Btu/h (output) (see specification plate on unit) II. Fuel/energy costs in your area 3 units/mbtu 4 Conversion Efficiency 5 $/MBtu delivered Home Heating Energy Conversion Cost/MBtu Cost If This Source Cost Efficiency Delivered Fuel Were Used Electricity $ /kwh 3 293 kwh/mbtu 4 1.00 5 Oil (#2) $ /gal 3 7.14 gal/mbtu 4 0.70 5 Natural gas $ /therm 3 10 therm/mbtu 4 0.80 5 LP gas $ /gal 3 11 gal/mbtu 4 0.80 5 Coal (bit.) $ /ton 3 0.039 ton/mbtu 4 0.65 5 Wood (128 ft 3 ) $ /cord 3 0.035 cord/mbtu 4 0.60 5 $ / 3 /MBtu 4 5 (other) 1 Developed by Hinrichs, Salvagin, and Scheider at SUNY Oswego 90831_appendixC.indd C-3
C-4 Appendix C 90831_appendixC.indd C-4
Appendix C C-5 90831_appendixC.indd C-5
C-6 Appendix C Name: Page 3 Summary Page III. A. For all rooms, total the heat loss per surface type (sum of rows): Conduction Losses Windows Doors Outside Walls Roof/Ceiling Basement Floor/Slab Infiltration Losses (see at right) Total Peak Hourly Loss (Btu/h) Sum of Rows % of Total Heat Loss 100% Air exchanges per hour (see Item 7 on factor sheet) Factor chosen: K 5 Volume of heated space 5 ft 3 (from p. 1) Infiltration loss 5 heat capacity of air 3 T 3 air exchanges/h 3 volume of heated space 5 0.018 3 65 3 K 3 volume of heated space B. Losses as a result of heat transfer from central heating systems: If hot air ducts or hot water baseboard supply pipes are not insulated, multiply Total Peak Hourly Loss by 1.20. If ducts/pipes are insulated, multiply by 1.10. Multiply by 1.0 if electric heat is used. C. Heat gains (yearly averages): Appliances and lighting Enter 2500 (2000 if water heater is in unheated space). People Enter 400 for each occupant (averaged). Solar Gain Enter 35 3 area of south-facing windows. Total Gains D. Peak net heat loss: Subtract total gains [C] from total losses [B]. E. Seasonal heating needs: Divide item D by 1,000,000 and multiply by the number of degree-days 3 24 65. F. Total heating season costs based on previous calculations using fuel/energy costs in your area (Part II, p. 1) Calculation based on $ /MBtu for kind(s) of fuel or energy used. Btu/h Btu/h Btu/h Btu/h Btu/h 5 Btu/h 5 MBtu 5 dollars 90831_appendixC.indd C-6
Appendix C C-7 G. Actual heating season costs taken from your bills. (Subtract domestic water heating costs if you use the same type of energy source for both space and water heating approximately 20% of the total bill. You can also find the cost by comparing winter and summer energy bills.) H. For comparison purposes, divide item D by the area of heated space and the number of degree-days and multiply by 24 65. I. Comment on any discrepancy between your results in F and G. 5 dollars 5 Btu/ degree-day/ft 2 90831_appendixC.indd C-7
C-8 Appendix C HEAT LOSS FACTORS FOR HOME ENERGY AUDIT CALCULATIONS (INCLUDES COMPOSITE CONSTRUCTION; CONSIDERS CONDUCTION LOSSES ONLY; T 5 65 F) Surface Type Factor (Btu/ft 2 /h) Standard Low 12 Hour Use of: 1. Windows and Sliding Glass Doors Factor Emittance Drapes Quilts Single pane 71.4 59.1 46.8 20.6 w/storm window 32.5 26.2 15.3 Double pane w 1 4 air space 37.8 29.6 16.4 w 1 2 air space 31.9 22.4 25.8 15.2 Heat mirror 14.4 Triple pane w 1 4 air space 25.4 21.4 13.5 w 1 2 air space 20.1 17.6 17.5 11.9 2. Exterior Doors (Excluding Sliding Glass Doors) Factor (Btu/ft 2 /h) (Calculate glass area in doors as windows) Wood: 11 4 no storm door 27.0 11 4 w/1 storm door 17.0 11 2 no storm door 24.0 11 2 w/1 storm door 15.0 12 3 solid-core door 21.0 Steel with foam core: 13 4 Pella 5.1 13 4 Therma-Tru 4.1 3. Exterior Walls (with Siding) Factor (Btu/ft 2 /h) Concrete block (8 ) 33.0 w/vermiculite-insulated cores 5.1 w/foam-insulated cores 3.3 w/4 on uninsulated stud wall 15.0 w/4 insulated stud wall 4.5 See Item 8 for special conditions of structures w/1 air space and ½ drywall 24.0 with infiltration barriers, adjacent unheated areas, and earth sheltering. 90831_appendixC.indd C-8
Appendix C C-9 Brick (4 ) w/4 uninsulated stud wall 16.0 w/4 insulated stud wall 4.6 Logs (6 ) 7.8 (8 ) 6.0 See item 8 for special conditions of structures Uninsulated wood frame w/2 3 4 construction 14.0 with infiltration barriers, adjacent unheated Insulated wood frame areas, and earth sheltering. w/11 2 fiberglass 7.3 w/31 2 fiberglass; studs 16 on center 5.3 w/31 2 fiberglass and 1 foam 3.2 w/6 fiberglass; studs 24 on center 3.4 w/6 fiberglass and 1 foam 2.5 w/6 cellulose 3.0 w/6 cellulose and 1 foam 2.3 Insulated double-wall frame 111 2 fiberglass 1.8 111 2 cellulose 1.6 131 2 fiberglass 1.6 131 2 cellulose 1.4 Solid polystyrene walls 6 2.5 8 1.9 For heated underground basement, use above factors 3 0.5 4. Roof/Ceiling Factor (Btu/ft 2 /h) No insulation 20.0 31 2 fiberglass 5.1 6 fiberglass 3.2 6 cellulose 2.8 12 fiberglass 1.5 12 cellulose 1.4 14 cellulose 1.2 Continued 90831_appendixC.indd C-9
C-10 Appendix C 5. Floor Factor (Btu/ft 2 /h) Over unheated basement or crawl space vented to outside Uninsulated floor 15.0 6 fiberglass floor insulation 2.6 Over sealed, unheated, completely underground basement a Uninsulated floor 8.0 Uninsulated floor w/1 foam on basement walls 3.4 w/3 ½ fiberglass on basement walls 3.2 6 fiberglass floor insulation 1.5 On concrete slab No insulation 6.0 1 foam perimeter insulation 1.4 2 foam perimeter insulation 1.0 6. Other To determine factors for construction not listed on these sheets, use 65/Rtotal 7. Air exchanges per hour K (Btu/h/ft 3 ) Old, uninsulated, not maintained K 5 4.0 Old, uninsulated house, maintained K 5 2.0 Average insulated house, well maintained K 5 1.0 New, well-insulated house K 5 0.5 New, superinsulated (12 walls) K 5 0.2 8. Notes a. Multiply percentage of exposed basement wall above frostline (3 ft below ground level) by 4.0 for a 6 fiberglass insulated floor or 20 for an uninsulated floor. (Omit window areas.) b. If walls are earth sheltered, multiply factor by 0.5. c. If walls are wrapped with Tyvek or Tu-Tuff infiltration barrier, multiply factor by 0.66. d. If a closed, unheated space (such as an unused room, hall, or garage) is adjacent to the exterior wall, multiply the factor by 0.66. 90831_appendixC.indd C-10