Determining Utility Rates

No estimation of heating costs is complete until the utility rates for the various fuels available are determined and included in the estimate. Utility rates depend on so many variables that we can

Table 4-14 Usage Estimates for Gas Water Heating*

Cold-Water

Temperature

North

South

Size

Northern

Central

Central

Southern

Of

Hot-Water

Localities

Localities

Localities

Localities

Unit

Requirements

40°F

50°F

60°F

70°F

0-BR

30 Gallon/Day

12.8

11.2

10.0

8.5

1-BR

40 Gallon/Day

16.4

14.7

12.9

10.9

2-BR

50 Gallon/Day

19.7

17.5

15.2

13.2

3-BR

60 Gallon/Day

22.9

20.5

17.7

15.3

4-BR

70 Gallon/Day

26.6

23.6

20.6

17.6

5-BR

80 Gallon/Day

30.2

27.0

23.5

20.2

’Estimates are given in therms per dwelling per month. Where wholesale electricity is to be used for lighting, refrigeration, cooking, and domestic hot water, the monthly demand for all purposes may be estimated at 2.65 watts per kWh.

Courtesy National Oil Fuel Institute

Table 4-15 Usage Estimates for Electric Water Heating*

Cold-Water

Temperature

North

South

Size

Northern

Central

Central

Southern

Of

Hot-Water

Localities

Localities

Localities

Localities

Unit

Requirements

40°F

50°F

60°F

70°F

0-BR

30 Gallon/Day

210

185

165

140

1-BR

40 Gallon/Day

280

250

220

185

2-BR

50 Gallon/Day

350

310

270

235

3-BR

60 Gallon/Day

420

375

325

280

4-BR

70 Gallon/Day

490

435

380

325

5-BR

80 Gallon/Day

560

500

435

375

’’Estimates are given in kWH per dwelling per month. Courtesy National Oil Fuel Institute

Calculate only an estimated cost, not a precise figure. The problem is to arrive at as accurate an estimation as possible.

Among the many variables involved in determining utility rates are the following:

1. Differing rate structures

2. Fuel/energy adjustment factors

3. Variations in energy block sizes and prices

4. Rate structure qualification procedures

5. Community utility taxes

6. Maximum demand charges

Differing rate structures exist for different facilities or usage. The problem is to determine which rate structure applies to the particular situation. This information can usually be obtained by contacting the local utility and consulting with the utility rate correspondent.

Although this is a simplified explanation, a typical utility bill is computed by adding the demand charge, the energy or commodity charge, and the fuel adjustment charge, and dividing by the total amount of electricity or gas used during the billing period. This produces the average electric or gas cost. The procedure is illus­trated in Table 4-16.

Table 4-16 Determining Utility Rates

Demand Charge

300 X $0.60 = $180.00 50 X $0.45 = $ 22.50 $202.50 Commodity Charges Therms Rate X Amount

3.0 X TФH = $150.00

2.0 X 4.0^ = 90.00

5. $240.00

Total commodity charges: 8 X $240.00 = $1920.00 Fuel adjustment (40,000 X $0.01819) 727.60

$2647.60

$1620 + $2647.60

Average gas cost——————————— = 10.6^/therm

40,000

Posted in Audel HVAC Fundamentals Volume 1 Heating Systems, Furnaces, and Boilers