Fritz: All Fritz

home *** CD-ROM | disk | FTP | other *** search

/ Fritz: All Fritz / All Fritz.zip / All Fritz / FILES / MISCEOUS / ZIP.LZH / ZIP.DOC < prev next >

Wrap

Text File | 1990-02-02 | 26KB | 423 lines

ZIP.DOC Page 1 A Short Guide to ZIP, Version 1.0 November 1988 ZIP, the Zip Code Insulation Program, determines economic levels of insulation for new and existing houses in any location in the United States, given the first three digits of its Zip code. Economic insulation levels are determined for attics, exterior walls, floors over unheated areas, slab floors, and basement and crawlspace walls. The economic levels computed by ZIP reflect the type of heating and cooling systems specified by the user, as well as system energy efficiencies, local energy prices, and current installed insulation costs. Local climate data for the three-digit Zip code are retrieved from the ZIP disk. Default energy and insulation price data are also retrieved from the ZIP disk. However, it is recommended that users override these latter default values with estimates of local energy and insulation prices, as requested during the analysis. ZIP is a public domain computer program developed by the National Institute of Standards and Technology (NIST, formerly the National Bureau of Standards) under the sponsorship of the United States Department of Energy (DOE)*. As ZIP is in the public domain, it may be copied and distributed freely. ZIP and its supporting data files are provided on a single 5-1/4 inch floppy disk for use with microcomputers having an MS-DOS operating system (typical IBM- PC/XT/AT and compatible systems). This "Short Guide" is a condensed version of the "User's Guide to ZIP 1.0, the Zip Code Insulation Program," (ORNL/TM-11009 or NISTIR 88-3801). The printed "User's Guide" provides comprehensive information about the ZIP program and includes documentation of its computational algorithms. However, for most users this "Short Guide" provides sufficient information to run ZIP successfully. For information on how to obtain the more comprehensive ZIP "User's Guide", write to David McElroy Oak Ridge National Laboratory Bldg 4508, Mail Stop 6092 PO Box 2008 Oak Ridge, TN 37831-6092 The ZIP program was originally written to calculate economic levels of insulation reported by 3-digit ZIP Code in the Department of Energy's "Insulation Fact Sheet" (DOE/CE-0180, January 1987). The "Insulation Fact Sheet" provides useful information related to the choice of insulation materials for particular applications and suggestions related to its proper installation. This program has now been enhanced and documented for more general use, allowing users to obtain more detailed recommendations based on local conditions. The "Insulation Fact Sheet" can also be obtained at the address shown above. ---------- * Neither NIST nor DOE assumes any liability resulting from the use of the information provided by the ZIP program or from any errors or omissions in the program. ZIP.DOC Page 2 The version of ZIP described here is intended for use by any government or private agency (such as a utility) being asked to provide advice to consumers on economic levels of insulation for new or existing houses. ZIP can also be used by insulation manufacturers, insulation installers, and by homeowners (either on their own personal computer or at some central location such as a home show, utility office, or energy conference). Where local building codes require more insulation than suggested by ZIP, the codes should take precedence. CALCULATION OF ECONOMIC LEVELS OF INSULATION The economic levels of insulation calculated by ZIP are based on an incremental type of analysis. Successive levels of insulation in each part of the house are evaluated independently to determine how far it pays to keep adding insulation and when to stop. For example, in an attic an economic analysis is performed at R-0 (no insulation), R-11, R-19, R-22, R-30, R-38, and R-49. As long as the additional insulation needed to increase the total R-value from one level to the next is found to be cost effective, that increment will be included in the recommended insulation level for that application. If it is not cost effective, that increment will not be included. In general, the more severe the climate, the higher the cost of energy, and the lower the heating and cooling system efficiencies, the more it pays to add insulation and the higher will be the economic level. Economic calculations in ZIP are based on a reduction in long-term heating and cooling costs. For new houses, a thirty-year life is used in calculating the economic level of insulation. That is, the economic level of insulation calculated for a new house will be the level which has the lowest present- value insulation cost plus energy cost over a thirty-year period. For existing houses, a twenty-year life is used in the calculations. In performing these calculations, a seven percent annual rate of return, over and above general inflation, is used to discount future savings to present value. If inflation is currently five percent, this is approximately equivalent to requiring a minimum twelve percent rate of return on the investment. Each increment of insulation must earn at least this rate of return to be considered cost effective. Residential energy savings are not taxed, so that this is in effect an after-tax rate of return on investment. Moreover, the first increments of added insulation typically return much higher dividends than the last increment. Thus the average rate of return on the entire investment tends to be considerably higher than the minimum acceptable level, especially if there is little insulation to start with. There are other benefits from installing economic levels of insulation in houses. These include increased occupant comfort, reduced demand for scarce energy resources, reduced peak energy demand, reduced pollution, and perhaps even reductions in global warming. However, none of these benefits is included explicitly in the ZIP analysis of insulation savings. ZIP.DOC Page 3 RUNNING ZIP To start ZIP, insert the disk into the default drive and enter 'ZIP'. (Alternatively, the files on the ZIP disk can be copied to a hard disk and run from that drive.) Enter the first three digits of the Zip code of interest as requested, and ZIP will respond with the reference location and the corresponding heating degree days (base 65F) and cooling degree hours (base 74F). The reference location is typically the location designated by the U.S. Postal Service as the main post office at the three-digit Zip code level. If the location is acceptable, press <Enter>; otherwise enter another Zip code. ZIP then asks the user to designate whether the analysis is for a new or existing house, the type and approximate efficiency of the heating and cooling systems, and the presence of ductwork in unconditioned spaces. Five different heating systems can be selected in ZIP: three furnaces types, including natural gas, fuel oil, and electric resistance; electric baseboard; and electric heat pump. Two electric cooling systems can be selected: central and window air conditioners. (An evaporative cooling system can also be selected. However, no cooling savings from insulation are calculated for this latter system.) In addition, the user can specify the approximate operating efficiency of the heating and cooling systems (low, medium, high, or very high). System specifications are needed to calculate the purchased energy savings corresponding to any given reduction in space heating and cooling loads. If there is ductwork in attics, crawlspaces, or other unconditioned spaces, an adjustment is also made to the equipment efficiency to reflect duct losses. Current energy prices for heating and cooling, corresponding to the type of systems selected, are then requested. Default values based on the DOE regional energy price data base are displayed. These values can be used but it is recommended that the user replace these with local energy prices in the units shown (e.g., kWh, therms, gallons). These prices should include all taxes and fuel adjustment costs (but not demand charges, if any*). If declining (or increasing) block rates are applicable (for example, kWh prices are often lower for kWh usage above 500 kWh per month than for the first 500 kWh), the energy cost should reflect the cost of the last units purchased each month (during the months of major usage), not the average cost for all units. If there are different prices for summer and winter usage (as is often the case for electricity), the price used for cooling should be based on the summer rate and the price for heating on the winter rate. Screen 1.1 shows the menu for selecting the insulation applications of interest to the user. Mark an 'X' in the box corresponding to each of the choices desired. Only data pertinent to the applications marked with an X will be requested after this point. -------- * ZIP does not evaluate benefits for reductions in the maximum rate of energy use in specific time periods. However, demand charges, which are needed to evaluate such benefits, are not typically included in residential rate schedules and thus this analysis is not applicable to most houses. ZIP.DOC Page 4 Screen 1.1 Menu for marking insulation systems of interest ╔════════════════════════════════════════════════════════════════════════════╗ ║ MARK INSULATION SYSTEMS OF INTEREST WITH AN X ║ ║ (Use cursor to move up and down, <Del> to erase X) ║ ║ ║ ║ ATTIC [X] ║ ║ EXTERIOR WALLS: ║ ║ Wood Frame [X] ║ ║ Concrete-masonry [X] ║ ║ FLOORS/CRAWLSPACES: ║ ║ Floors over unheated/uninsulated spaces [X] ║ ║ Slab floors [X] ║ ║ Crawlspace walls [X] ║ ║ BASEMENT WALLS - DEEP: ║ ║ Exterior Insulation [X] ║ ║ Interior Insulation [X] ║ ║ BASEMENT WALLS - SHALLOW: ║ ║ Exterior Insulation [X] ║ ║ Interior Insulation [X] ║ ║ ║ ║ Press <End> When finished. ║ ╚════════════════════════════════════════════════════════════════════════════╝ If insulation in an existing house is being evaluated, the user is asked to identify the approximate levels of insulation in the attic, wood-frame walls, floors over unheated areas, and crawlspace walls, if any. The approximate level is selected from a menu of choices by code number, not by the actual R-value. Default insulation costs for each application checked are then displayed. For most applications, three to eight different insulation levels are shown along with default estimates of their installed cost. ZIP will evaluate each of these levels to determine which is the most cost effective in this analysis, using the costs shown. The user should change these default insulation costs to reflect the current cost of insulation for the application of interest. The guidelines in table 1 should be considered in determining appropriate insulation costs. The insulation levels and corresponding costs in the insulation data file used by the ZIP program are the same for both new and existing houses, with the exception of the insulation for exterior wood-frame walls. In new houses, it is much less costly to insulate a wall before the inside surface is finished than it is to blow insulation into an existing wall cavity. Moreover, for a house under construction, thicker walls or insulated sheathing can be used to improve the its overall insulation effect, while in a completed house, the addition of insulation is generally limited to the available cavity in the existing wall. ZIP.DOC Page 5 Table 1. Important considerations in specifying insulation costs o All costs are to be specified in terms of insulation resistance (R) value, not thickness. o All costs are shown as cost per square foot or cost per linear foot for the indicated R-value. If you get cost estimates for the total job, you must convert them to dollars per square foot or per linear foot as indicated. o The insulation costs should include both material and labor costs if professionally installed. o If you are doing the job yourself, you can omit labor costs, or include the cost of your time, as you prefer. o All insulation costs should include the cost of structural modifications or coverings if these additional costs cannot be justified for other purposes. o Each R-value for any given application is expected to cost more than the previous R-value, never the same or less. o Technically speaking, it is the difference in cost for each additional R-value relative to the previous R-value that is most important in the analysis. Therefore take care to make the cost differentials reasonable. ZIP REPORT FORMAT The results of the economic analysis for the designated location are displayed on the screen, as shown in screen 1.2 for a new house in ZIP Code 809XX (Colorado Springs). The reference location is typically the location designated by the U.S. Postal Service as the main post office for the three- digit ZIP Code. The number of annual heating degree days (base 65F) and cooling degree hours over 74F are shown for the designated location, along with the heating and cooling systems used in the analysis. Screen 1.2 shows the screen display of economic levels for all of the components that can be evaluated by ZIP. However, economic levels are displayed only for those components selected for analysis by the user for the particular application. Screen 1.3 shows additional information for floors over crawlspaces and crawlspace walls that can be displayed by pressing <PgDn>. To return to the ZIP analysis screen, press <PgUp>. Energy savings and their estimated dollar value computed in the analyses are not shown on the screen display. These calculations are based on uniform surface areas for a typical house under average operating conditions for a typical year. They would not provide any meaningful estimate of savings for the user's house. Note that the economic levels of insulation both under floors over crawlspace and on crawlspace walls are shown. However, only one of these would be used in most houses. For crawlspaces that do not need ventilation and can be closed off, it is usually more economical to insulate the walls than the floor if the wall area is less than the floor area. If the crawlspace cannot be safely closed off, the floor above should be insulated instead. In this latter case, care must be taken to insulate water pipes and any ductwork in the unheated area. ZIP.DOC Page 6 Screen 1.2. Display of ZIP Analysis for New House ╔════════════════════════════════════════════════════════════════════════════╗ ║ Economic Insulation Levels for Zip 809XX ║ ║ Reference Location: Colorado Springs, CO ║ ║ Heating system: HEAT PUMP Cooling system: HEAT PUMP ║ ║ -------------------------------------------------------------------------- ║ ║ New House Construction ║ ║ ║ ║ Attic Insulation R-38 ║ ║ Wood-Frame Wall Insulation R-19 ║ ║ Masonry Wall Insulation R-11 ║ ║ Floors over Crawlspace ║ ║ (If crawlspace walls are uninsulated) R-30 ║ ║ Crawlspace Wall Insulation ║ ║ (If floor above is uninsulated) R-19 ║ ║ Slab-Edge Insulation R- 4 ║ ║ Insulation of Basement Walls: ║ ║ Exterior Insulation for Deep Basement R- 8 ║ ║ Interior Insulation for Deep Basement R-11 ║ ║ Exterior Insulation for Shallow Basement R- 8 ║ ║ Interior Insulation for Shallow Basement R-11 ║ ║ ║ ║ -------------------------------------------------------------------------- ║ ║ Press <PgDn> for additional information. ║ ║ Press <SHIFT> <PrtSc> to print this screen if desired. ║ ║ Press <ESC> to exit, R to do another analysis: ║ ╚════════════════════════════════════════════════════════════════════════════╝ Screen 1.3 ╔════════════════════════════════════════════════════════════════════════════╗ ║ Additional information ║ ║ ║ ║ Insulate either the floor over the crawlspace or the crawlspace ║ ║ walls, not both. Consult an insulation specialist to determine ║ ║ which is more appropriate for your house. ║ ║ ║ ║ Crawlspace walls should only be insulated if the crawlspace is ║ ║ closed off, unventilated, and dry all year. The ground should ║ ║ be covered with a vapor barrier (e.g., 4- or 6-mil polyethylene ║ ║ sheeting) to minimize moisture migration into the crawlspace. ║ ║ Note: some building codes may not allow unventilated crawlspaces. ║ ║ If radon gas is a problem at the building site, closing off the ║ ║ crawlspace may not be advisable. ║ ║ ║ ║ When insulating floors over crawlspaces or other unheated areas, ║ ║ make sure that water pipes are freeze-protected and ductwork is ║ ║ well insulated in those areas. ║ ║ ║ ║ -------------------------------------------------------------------------- ║ ║ Press <SHIFT> <PrtSc> to print this screen if desired. ║ ║ Press <PgUp> to show economic insulation levels: ║ ║ ║ ╚════════════════════════════════════════════════════════════════════════════╝ZIP.DOC Page 7 The following files can be found on the original ZIP disk: ZIP.EXE The executable version of ZIP. CLIMATE.DAT A file of climate data, keyed to three-digit ZIP Codes. INSCOST.NEW A file of default insulation price data for new houses. INSCOST.RET A file of default insulation price data for existing houses. ZIP.BAS The source code version of ZIP. ZIP.DOC A short explanation of the ZIP program. Files of default energy price projections for DOE regions 1 through 10:* ENPRICES.1 ENPRICES.4 ENPRICES.7 ENPRICES.2 ENPRICES.5 ENPRICES.8 ENPRICES.3 ENPRICES.6 ENPRICES.9 ENPRICES.10 All of these files (except ZIP.BAS and ZIP.DOC) are needed to run ZIP. Copy these files to a new disk for running the program, and store the original disk in a safe place. There is no disk operating system (DOS) on the original ZIP disk. Thus you should copy the files on this disk to a disk which has been formatted with DOS or to your fixed (hard) disk. If you are copying these files to a fixed disk, you might want to copy them to a subdirectory named ZIP. Note (2-1-90): ZIP 2.0 is currently in the testing stage and is expected to be released in the spring of 1990. ZIP 2.0 will allow the user to evaluate economic levels of insulation for ducts in unconditioned spaces and for cathedral ceilings. It will also determine whether or not a water heater insulation jacket is cost effective based on the water heater type and remaining life. ZIP 2.0 will have other enhancements to make the program easier to use. For information on the availability of ZIP 2.0 contact: Applied Economics Group National Institute of Standards and Technology Bldg 101, Rm A415 Gaithersburg, MD 20899 (301) 975-6131 ----------- * DOE regions are as follows: 1 ME, NH, VT, MA, CT, RI 6 TX, NM, OK, AR, LA 2 NY, NJ, 7 KA, MO, IA, NE 3 PA, MD, WV, VA, DC, DE 8 MT, ND, SD, WY, UT, CO 4 KY, TN, NC, SC, MS, AL, GA, FL 9 CA, NV, AZ, HI 5 MN, WI, MI, IL, IN, OH 10 WA, OR, ID, AK ZIP.DOC Page 8 A technical note on the default energy and insulation prices accessed by ZIP from the ENPRICES and INSCOST files All prices, as displayed on the screen, are currently expressed in 1988 dollars. They are automatically converted to 1988 dollars from 1985 dollars (as they are stored on the disk) using a 12 percent cumulative inflation factor (i.e., a GNP deflator of 1.12) over the three year period. If you intend to change the default prices in the data files you must be careful to specify the proper inflation factor (i.e., GNP deflator) in these data files. If, for example, you change these price data in the files to 1989 dollars for use in 1989, then the GNP deflator should be set to 1.0 (i.e., zero cumulative inflation). If you wish to retain the price data currently in the files but want to convert it to a later year (e.g., 1989) in the screen display, you must change the GNP deflator in the files to reflect the cumulative inflation from 1985 to date. These changes can be made with a simple text editor, saving the file in the text (ASCII) mode when finished. See the ZIP User's Guide, pages 26 and 27, for the format of the insulation price files. Pages 24, 25 and 29 show the format for the energy price files. Note that the energy price projections in the ENPRICES files must be stated in constant dollars, i.e., net of general price inflation. The year in the second line (1985 in the current file) designates the first year for which a price is given. The integer on the third line (26 in the current file) designates the number of years for which prices are contained in the file. The current year for screen display is determined from the clock in your computer; therefore it must be set to the proper year. The current price for screen display is based on the price for the current calender year, multiplied by the GNP deflator in the file. The energy prices for future years contained in the ENPRICES file are used to determine the rate of energy price increase from year to year (net of general inflation), regardless of whether you use the default prices or enter your own price. That is, if the 1988 price for natural gas is 7.02 and the 1989 price is 7.47, then the implicit assumption is that natural gas prices will rise at a rate 6.4% greater than prices in general for that year. If the number of prices in the price file is less than the period of analysis (20 years for existing houses, 30 years for new houses), a zero energy price increase is assumed for those years in which no energy prices are available.