LAING AUTOCIRC PUMP
Operating Cost Savings Summary
Based on 3 bedroom home with 4 occupants, water heater 60 feet from
farthest fixture, non-insulated ¾" copper hot water supply line with
Laing Autocirc Undersink System Pump at the farthest fixture from water
heater.
Gas Water
Heater
Chart Calculation Factors For Gas Water Heater:
1.
Savings
of 34.2 gal./day of previously heated water wasted from discharging
down drain. (350 days/yr.
= 11,970 gal./yr.)
2. Water
heater is set at an average temperature of 140°F, has an efficiency
rating of 65%, and a heat rise temperature value of 100°F.
3. The
incoming water temperature is 40°F.
4. Gas
cost per therm includes taxes and charges.
5. Gas
savings in therms result from not having to heat wasted water less the
gas used to offset piping heat losses. (101.71 therms/yr.)
6. Additional
piping heat losses are based on 10 BTU/hr./ft. in 60 feet of 3/4"
uninsulated hot water supply piping.
7. Water
cost is based on $2.02/100 cu. ft. and sewer surcharge cost is based on
$1.35/100 ft.3. (Total
water cost savings = $53.79/yr.)
8. Cost
to run pump = $1.24/yr. (Based on $0.10/kWh, pump running 4 min./hr.,
16 hrs./day, and 350 days/yr.)
9. Numbers
are rounded off.
Electric Water
Heater
Chart Calculation Factors For Electric Water Heater:
1.
Savings
of 34.2 gal./day of previously heated water wasted from discharging
down drain. (350 days/yr.
= 11,970 gal./yr.)
2. Water
heater is set at an average temperature of 140°F, has an efficiency
rating of 100%, and a heat rise temperature value of 100°F.
3. The
incoming water temperature is 40°F.
4. Electrical
energy savings in kWh result from not having to heat wasted water less
the energy used to offset piping heat losses. (1,924.69 kWh)
5. Cost
per kWh includes taxes and charges.
6. Additional
piping heat losses are based on 10 BTU/hr./ft. in 60 feet of 3/4"
uninsulated hot water supply piping.
7. Water
cost is based on $2.02/100 cu. ft. and sewer surcharge cost is based on
$1.35/100 ft.3. (Total
water cost savings = $53.79/yr.)
8.
Cost to run pump = $1.24/yr. (Based on $0.10/kWh, pump running 4 min./hr.,
16 hrs./day, and 350 days/yr.)
9. Numbers
are rounded off.
Notes:
1. Use of insulated copper supply line on Autocirc system would result in
additional savings.
2. Actual savings may differ from household to household depending on a variety of
factors including water use habits, length of hot water supply line, number of home
occupants, etc.
Above summary based on study and analysis prepared
by Edward Saltzberg and Associates, consulting mechanical engineers. Copies of this
detailed analysis are available on request from Laing Thermotech, Inc.
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