Guide To Pool Heating

Page 34 of 51

How to Calculate Pool Heating Costs
When You Use Natural Gas

This is a cost estimating template. Simply fill in the appropriate numbers and perform the
simple calculations shown. This template will help you to determine the cost of operating a
swimming pool heater fueled by natural gas.

A.

Cost Per Therm of Natural Gas
Note: Call your gas company for your rate
One Therm = 100,000 Btus
Example: 75.7¢ per Therm

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B.

BTU/Hour Rating of Natural Gas Heater
Note: Look on Gas Heater Name Plate
Or, call the pool dealer who installed heater.
Example: 150,000 Btus/hour rating.

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C.

Efficiency Rating of Heater
Note: Look on Heater Name plate oruse .8(80%)

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D.

Therms per hour = ((B ÷ C) ÷ 100,000)
Note: Input btus xefficiency = Output btus (rating)
Example: 150,000 output rating ÷ .8 = 187,500
187,500 input required ÷ 100,000 = 1.875 therms/hr

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E.

Hours per day heater is used

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F.

Daily Operating Cost = (A x D x E)

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Example:
.757 x 1.875 therms/hrx 10 hrs/day = $14.19/day

G.

Days in the month heater is used

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H.

Monthly Operating Cost = (F x G)

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Example:
14.19x 20 days per month = $283.80

The cost of operating a natural gas swimming pool heater may be substantial. Many reports
indicate $150 or more per week. In Minnesota during 1988, a typical natural gas heater budget for
the pool season was $1000-1200.00 each year.