ON MARCH 3, 2009


Development of Plan


Waste and inefficiencies in the Town’s street lighting system have been a focus of the Jaffrey Energy Committee.   The Town’s ad hoc Street Lighting Committee was established by the Selectmen in late 2007 at the request of the then Chair of the Energy Committee, Harry Young.  The Selectmen directed the Committee to “study the town’s lighting to save money and reduce global warming.” The Committee has worked hard, conducting a comprehensive survey of the Town’s streetlights, researching the literature regarding streetlight purposes and uses, adopting a statement of guiding principles and criteria, and developing a plan for fundamental change in the Town’s streetlight system.


Guiding Principles Adopted By the Committee:


            Provide Needed Lighting:  Impelled by critical public safety and community concerns, the Committee is seeking to ensure that the Town of Jaffrey has an aesthetically appropriate street lighting system sufficient to meet the needs of its residents.


            Conserve Energy:  Impelled by critical global warming and energy security concerns, the Committee is seeking to reduce, to the maximum extent feasible consistent with the Town’s street lighting needs, the energy consumed by particular streetlights and by the Town’s entire street lighting system.


            Save Money:  Impelled by critical Town budget and tax burden concerns, the Committee is seeking to reduce, to the maximum extent possible, the recurring and long-term costs of the Town’s street lighting system.



Guiding Criteria Adopted by the Committee


            Intersections:  In general, there should be streetlights sufficient to signal the location of each intersection of major public roads where there is significant vehicular traffic.


            Sidewalks:  In general, there should be streetlights sufficient to illuminate sidewalks in densely populated areas where there is significant pedestrian movement.


            No Wasted Light:  The light provided by each street light should be no more than what is necessary to accomplish its purpose, should not illuminate the night sky, and should not shine into neighboring windows or yards.


            Energy Efficient Lighting:  The Town’s new street lights should be state-of-the-art in terms of the light (lumens) provided per watt of energy consumed and in terms of their long-term durability and maintenance needs.


            Consistent Lighting:   In general, there should be one consistent type of street light, providing light of the same color (whether yellow-looking as in high pressure sodium lights or white-looking as in metal halide lights), used throughout Town.”



Plan Recommended by the Committee for Selectmen and Public Review


- The PSNH inventory for the Town currently shows 217 lamps.  The Committee found 5 additional lamps that are not in the PSNH inventory.  The Committee’s baseline is, therefore, 222 lamps.[1]


- The Committee recommends removing 86 lamps.  Lamp-by-lamp recommendations are shown on the accompanying maps and spread sheets.  (The Committee’s initial list of 96 possible removals has been reduced to 86 recommended removals after review with Police Chief Oswalt.)


- The Committee recommends replacing the 123 remaining lamps that are outside of the Historic District with Full Cut-Off Metal Halide lamps rated at 70 Watts and 5000 lumens[2].


- The Committee recommends keeping the Jaffrey Historic District lighting pending further review with the Jaffrey Historic District Commission.  For these 13 incandescent lamps, PSNH will establish a separate account in the name of the Jaffrey Historic District Commission.


- Estimated results[3] are $29,329 in Annual Dollar Savings (after payback period) and 17,695 in Wattage[4] (Energy) Savings.  Over 25 years, the estimated dollar savings will amount to $733,225.  This amounts to a 64% reduction in annual Town costs and a 64% reduction in energy consumed.   The PSNH payback period, assuming an estimated $70,000 conversion cost, is about 2.4 years (or about 3.2 years if Town chooses to realize about $7,362 per year in net savings right away).



Respectfully Submitted on March 3, 2009,

for the Jaffrey Streetlight Committee

by its Chair, Harry Young.


[1] These 222 lamps exclude DOT and Town owned lamps.  The PSNH Baseline of 217 Lamps includes: 

            - 206 PSNH-inventoried lamps outside of Historic District, of which:

141 are Mercury Vapor @ 100 watts and 3,500 lumens each.

36 are Mercury Vapor @ 250 watts and 11,000 lumens each.

12 are Mercury Vapor @ 175 watts and 7,000 lumens each.

4 are Mercury Vapor @ 400 watts and 20,000 lumens each.

4 are Metal Halide @ 100 watts and 8,000 lumens each.

3 are High Pressure Sodium @ 50 watts and 4,000 lumens each.

2 are Metal Halide @ 70 watts and 5,000 lumens each.

1 is High Pressure Sodium @ 70 watts and 5,800 lumens.

1 is High Pressure Sodium @ 100 watts and 9,500 lumens.

1 is High Pressure Sodium @ 150 watts and 16,000 lumens.

- 11 PSNH-inventoried lamps in Historic District, of which:

8 are Incandescent @ 105 watts and 600 lumens each.

3 are Incandescent @ 105 watts and 1,000 lumens each

- Total Wattage required to power all PSNH Lamps is 28,825, of which:

27,670 watts are required for Lamps outside of Historic District.

1,155 watts are required for Lamps in Historic District.

- Total Annual Cost for all Lamps at current PSNH rates is $45,809.


[2] The Committee had hoped to be able to recommend use of 50 watt, 4000 lumen metal halide lamps, but was informed by PSNH in early February 2009 that PSNH had decided that these lamps were problematic in their design and would not be supported by PSNH.  The lumen maintenance curve for metal halide is superior to mercury vapor.  In its 2nd, 3rd & 4th years of operation, the  5000 lumen metal halide lamp will likely be providing about 4000 lumens after the 1st year, 3500 lumens after the 2nd year, and about 3250 lumens in the 3rd & 4th years.  This is to be compared with Jaffrey’s typical 3500 lumen mercury vapor light which is likely to provide about 2800 lumens after the 1st year, 2400 lumens after the 2nd year, 2100 lumens after the 3rd year, and 1800 lumens after the 4th year.

[3] Adjustments to these estimates will be made after final reconciliation of the PSNH inventory with the Committee’s list of lights.

[4] Adjustments to this wattage estimate need to be made to account for differences in the power (wattage) consumption requirements of the ballasts that will be used with the metal halide lamps.  The adjustments will likely be relatively minor.