Note: For all computers except the unexpanded VIC-20, add the DATA statements in lines 2000-2995 (Program 7) to your version of the heating audit program. Add the DATA statements of lines 2000-3000 (Program 14) to your version of the cooling audit program. For the
VIC-20 add only DATA statements (from Programs 7 and 14) for the cities nearest your home plus line 2990 for the heating audit or line 2995 for the cooling audit.
Have you, like thousands of Americans, added insulation, storm windows, a setback thermostat, and caulking to improve the energy efficiency of your home? Other than the 15% energy credit you could claim on your taxes starting in 1979, it is difficult to know what savings you are achieving with these substantial investments of time and money. A colder than normal winter will cause increased fuel use for heating, which may or may not overshadow the energy savings by insulating. On the other hand, the winter of 1979-80 was so mild in most parts of the United States that it brought significant fuel savings for most homeowners whether they insulated or not. However, energy costs have increased so much in some areas and for some fuels that these consumers may not have achieved a monetary savings.
The cost for heating or cooling a house is due to three things:
1) outside temperature 2) thermostat setting
3) insulation (including air infiltration)
Only the last two are under your control. The most cost-effective action you can take is to raise the thermostat in the summer and lower the thermostat in winter. The next most effective is to increase the insulation. But even after you have done this, the fuel use will still be driven by the outside temperature. In order to compare the severity and predict fuel use, meteorologists have developed two concepts:
1) Heating degree day 2) Cooling degree day
Heating degree day is an estimate of the heating necessary in the winter, and cooling degree day is an estimate of the cooling necessary in the summer. Both are calculated from the maximum and minimum temperatures and summed each day to accumulate monthly and yearly totals.
Heating degree days accumulate on days with an average temperature cooler than 65 °F, and cooling degree days
accumulate on days with an average temperature warmer than 65 °F. These data are recorded for several hundred stations in the United States and are available in "Local Climatological Data," a publication from the U. S. Dept. of Commerce, National Climatic Center, Federal Building, Asheville, NC 28801. The concepts of the cooling and heating degree days have shown excellent correlation with fuel use in my residence (see Figures 1 and 2) both in heating and air conditioning on a month by month basis, and an even higher correlation for an entire season. This correlation prompted me to develop a BASIC program for calculating an energy use rate for one year and predicting energy use in the following years based on degree days. Using this technique, you can calculate energy fuel savings as well as economic savings, even though the weather, energy cost, and energy efficiency of your home are changing month by month and year by year.
Each program requires less than 8K and can be shortened considerably by selectively eliminating DATA statements to restrict the geographical coverage. Each program requires the homeowner to have records of fuel use and cost for two years or more. The programs can evaluate efficiency from the years 1974 through and including 1980. Any type of fuel can be used; just remember that the units you input will be the units calculated for the fuel savings. Similarly, the rate is given as cost/fuel units, and so is dependent upon the units you input. Changing fuels or changing residences invalidates the technique.
The heating season is from October 1 to May 1, and the cooling season is from April 1 to November 1; seasons are made extra long in order to accommodate the wide range of climates in the United States. Because many fuels are used for other purposes such as hot water heating, home lighting, etc., the off season minimum usage is used to remove these factors from the seasonal weather effects. Thus the heating program requests the July fuel use, and the cooling program requests the January fuel use. Should a user live between cities, listed runs for all cities in that region will allow interpolation. Following are some key variables:
ST$= state
CT$=city
H(1,I) = degree days for 1974 for city I x = fuel use/degree days for base year H = predicted fuel use minus actual fuel used RATE(k) = cost/fuel unit
F(k) = fuel unit D(k) = cost k = year
MI = fuel used in minimum month
The precision of this technique is good, but may predict only small savings or even loss in years when no energy conservation practices were in effect. This uncertainty is due to the variance between day and night temperatures, which is not always well represented by the mean temperature for the day.
S I 125
-J100
•§5 75 3 50
X o 25
Heating Degree Days
Natural Gas Used
500 Q 400 300
i
DO
Oct. Nov. Dec. Jan. Feb. March April May June July
200-5
100 |
0
Figure 1. Heating Degree Days by Month for 1979-80 in Houston, TX and Natural Gas Used in the Author's Residence.
2400
Cooling Degree Days ^~
/ /
\ \ Kilowatt Hours 500^
400 £300 Jf
200 £
100 §
April May June July Aug. Sept. Oct. Nov. Dec. Jan.
Figure 2. Cooling Degree Days by Month for 1979 in Houston, TX and Kilowatt Hours used in the Author's Residence.
Table 1 * Sample Run Of Heating Fuel Audit.
HEATING FUEL AUDIT
STATE (DON'T ABBREVIATE)? TEXAS
THE WINTER OF 73-74 IS CALLED 74, CHOICES ARE 74 TO 80 STARTING YEAR? 78
LAST YEAR? 80
CHOICES OF INPUT ARE BY YEAR OR MONTH BY YEAR (Y OR N)? Y
UNITS OF FUEL CAN BE ANYTHING: GALLONS, KWH, CUFT, ALL FUEL ENTRIES MUST BE THE SAME UNITS
YEAR= 78
FUEL USE FOR OCT 1 TO MAY 1? 650 COST(DOLLARS)? 205.05
YEAR= 79
FUEL USE FOR OCT 1 TO MAY 1? 526 COST(DOLLARS)? 182.7
YEAR= 80
FUEL USE FOR OCT 1 TO MAY 1? 318 COST(DOLLARS)? 120.6
FUEL USE FOR JULY? 10
STATE CITY
1 TEXAS BROWNSVILLE
2 TEXAS AMARILLO
3 TEXAS FORT WORTH
4 TEXAS HOUSTON
CHOOSE # OF CITY? 4
CHOSEN CITY= HOUSTON RATE(1ST YR)= .31 YEAR
79 80
RATE .34 .37
FUEL SAVED 15 178
DOLLARS 5.51 67.54
SAVED
(+ = SAVINGS,- = LOSS)
Table 2* Sample Run Of Cooling Fuel Audit.
COOLING FUEL AUDIT
STATE (DON'T ABBREVIATE)? TEXAS
THE SUMMER OF 1974 IS CALLED 74, CHOICES ARE74 TO 80 STARTING YEAR? 78
LAST YEAR? 80
CHOICES OF INPUT ARE BY YEAR OR MONTH BY YEAR (Y OR N)? Y
UNITS OF FUEL CAN BE ANYTHING: GALLONS, KWH, CUFT, 100 CUFT ALL FUEL ENTRIES MUST BE THE SAME UNITS
YEAR= 78
FUEL USE FOR JANUARY? 679 CITY
CHOSEN CITY= HOUSTON RATE(1ST YR)= .03
1
oo BYMONTH) MOREREQUIRED
Program1.OSIVersion* IREMHEATINGFUELAUDIT 10REM IIREMPROGRAMREQUIRESHEATINGFUELUSE(ANNUALOR 12REMHEATINGMONTHSAREOCT1TOMAY1,2YRSOR 13REMOUTPUTISFUELSAVINGS,AND*SAVINGS 15REM3KK1K}K}K}K!K]KX(]K}K3K}K}K}K}K]K}K)K4(}K}K}K)KX(}KX)K)K)K}K)K)K)K}K^)K}K)K>K)K}K)K}K)K)K}K)K)K}K 17DEFFNTRC(E)=INT(E*10Q)/100 20PRINTTAB(12)?"YEARBYYEARHEATINGCONSERVATIONAUDIT"{PRINT{PRINT 22GOSUB500{INPUT"STATE(DON'TABBREVIATE)"?B* 23FORI=1TO7{READM*(I){NEXT{PRINT 25PRINT"THEWINTEROF1973-74ISCALLED74,CHOICESARE74TO80" 27PRINT{INPUT"STARTINGYEAR"{YS{INPUT"LASTYEAR"{YE{PRINT 30L»YE-YS+iJPRINT"CH0ICE8OFINPUTAREBYYEARORMONTH"{PRINT 40INPUT"BYYEAR(YORN>l>;A«:iFASC(A*)<>89THEN>100 41PRINT{PRINT"UNITSOFFUELCANBEANYTHING{GALLONS,KWH,CUFT, 100CUFT" 43PRINT"ALLFUELENTRIESMUSTBETHESAMEUNITS"{GOSUB500JPRINT 47FORI=1TOL{PRINT"YEAR-"JINT(YS+I-1) 48PRINT'TUELUSEFOROCT1TOMAY1"{{INPUTF(I){INPUT"COST(DOLLARS)" 90GOSUB500{NEXT{GOTO200 100FORI=1TOL.{GQSUB50Q{PRINT"YEAR«"{INKYS+I-1){F0RJ-1T07 105PRINT-FUELUSEFOR"JM»<J>HINPUTFtPRINT"COSTFOR"{M*(J){JINPUTD 110F(I)-F(I)+F{D(I)=D(I)+D{NEXT{NEXT 200INPUT"FUELUSEFORJULY"{MI{1=1
Ul C C C C ' O O C ^G O O C> C O C C^ C C' O C: C C) C O C C C O C C
3 ))))))))) 3 )))))))))))))))))))))
220READST*,Cn*(I),H(l/I),H(2,I),H(3,I),H(4,I),H(5,I),H(6,I),H(7,I) 230IFLEFT*(ST*,7)-LEFT*(B*t7)THENI-I+1 240IFST*-"END"THEN250 245GOTO220 250J-I-l:LL-YS-74+i:PRINTTAB(IS)?"STATE"?TAB(25)?"CITY" 255FORI-1TOJ 260PRINTTAB(10)?I?TAB(15)?B*?TAB(25)?CT*(I):NEXT 270INPUT"CHOOSE*OFCITY"?IJPRINTJGOSUB500 280X=(F(1)-7*MI)/H(LL,I)JRATE(1)===D(1>/F(1):H=FNTFI:C(RATE(1)) 282PRINT"CHOSENCITY="?CT*(I>?TAB(37)?"RATE<1STYEAR)-"JTAB<58>JH 285PRINTtPRINTTAB(5)?"YEAR"? 290PRINTTAB(16>?"RATE"?TAB(25)J"FUELSAVINGS"?TAB(42)?"SAVINGS 295 300 312 320 340 500 RETURN 1999DATAOCTOBER,NOVEMBER,DECEMBER,JANUARY,FEBRUARY,MARCH♦APRILPRINTTAB(16>?"RATE"?TAB(25)?"FUELSAVINGS"?TAB (DOLLARS)" F0RK=2T0L H~H(LL+K™1»I)*X+7*MI-F(K>XRATE(K) H=FNTRC(H){RATE(K)«FNTRC(RATE(K)>D(K)/F(K)tC=H*RATE(K) C=FNTRC(C) PRINTTAB(5)?INT(YS+K~1>?TAB(15)?RATE(K)?TAB(28)?l NEXT:PRINT:GOSUB500;PRINTTAB(20)?"(+=SAVINGS)(•LOSS)":GOT0255