SIR: Savings to Investment Ratio

Of Green Water Heating Systems Averaged Over 5 U.S. Climate Zones

Cilmate Zone Factor (CZFn) Ohio SIR Maine SIR New York SIR

From Electric Water Heating Situation Analysis (EEI/DOE 12/6/96)

 

 

Heavy Residential User of 6618 kWh/yr Costing $562.53 @ 8.5/kWh1

System

Type

 

Measure

Cost

Measure2

Life

(years)

Present3

Value Factor

Savings kWh/yr

E-SIR4,5

kWh/$

NAECA Standard

66 gal.
Tank Cost: $275

$500

10

(Gas: 9)

7.7

(7.1)

 

N/A

A

Multifunction HPWH

$1000

13

9.4

4100

38.6

B

Add-On HPWH

$860

15

10.4

3510

42.5

C

Solar [Thermal]

$2750

30

15.4

3080

17.3

D

GFX Model

G3-60 or S4-60

$400

30

15.4

2250
PP&L: 2347

86.6

PP&L: 91.8

E

Tankless

$500

15

10.4

1280

26.5

F

Desuperheater

$600

13

9.4

1020

16.0

CD

Solar & GFX

$3150

30

15.4

5330

26.0

BD

HPWH & GFX

$1260

15

15.4

5940

72.4

Medium Residential User of 3764 kWh/yr Costing $318.75 @ 8.5/kWh

System

Type

 

Measure

Cost

Measure

Life

(years)

Present

Value

Factor

Savings kWh/yr

E-SIR

kWh/$

NAECA
Standard

66 gal.
Tank Cost: $275

$500

10

(Gas: 9)

7.7

(7.1)

 

N/A

A

Multifunction

HPWH

$1000

13

9.4

2500

23.5

B

Add-On HPWH

$860

15

10.4

2070

25.1

C

Solar [Thermal]

$2750

30

15.4

2420

13.5

D

GFX Model

G3-60 or S4-60

$400

30

 

15.4

1280
PP&L -1660

R-2000 -

17606,7,8

49.3

PP&L - 63.9

R-2000 -

67.8

E

Tankless

$500

15

10.4

1280

26.6

F

Desuperheater

$600

13

9.4

610

9.53

CD

Solar & GFX

$3150

30

15.4

3700

17.3

BD

HPWH & GFX

$1260

15

15.4

3350

40.8

FOOTNOTES

  1. Estimates for whole-house On-Demand (Tankless) water heaters were substituted for Point-of-Use units because they also eliminate standby loss and have lower installed costs as compared to EEI/DOE estimates of $1800 & $1100 for multiple Point-of-Use units for heavy users & medium users, respectively. (See Final Report for DOE/EEI Joint Water Heater Initiative, Electric Water Heating Situation Analysis, Reference #31186, Final Report to EEI/DOE December 6, 1996 by A.D. Little, Inc., Acorn Park, Cambridge, MA 02140-2390)
  2. Measure Life (ML) in years from Final Report Appendix A, pg. 10.
  3. Present Value Factor (PVF) = 20*[1-(1/1.05)^ML]**
  4. E-SIR = (PVF)* (kWh savings)/(Measure Cost)
  5. SIR = E-SIR * CZFn * kWhcost
  6. Energy Savings for GFX & GAS Water Heater = 96 Therm; from Canadian R-2000/Energuide Credits.
  7. E-SIRGAS/GFX = 3.96 Therm/$
  8. SIRGAS/GFX = 3.96 @ $1/Therm
  9. Example: Ohio SIR @ Ohio Edison Rate = 11/kWh in CZ2

**Equations courtesy of Nick Milano, Energy Program Developer,

Ohio Office of Energy Efficiency, 614-466-8436 (Fax: 1864)

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