Methodology & sources
Where every number comes from.
A bracketed number like [2] anywhere on this site points to a source listed at the bottom of this page. A figure with no footnote is either from the specimen building or labeled as an assumption.
Every action in a Payback Plan gets three numbers: what it saves per year, what it costs up front, and how long until the savings cover the cost. Actions are ranked by that last number, fastest first, so a board can start with what pays back soonest.
Savings are always counted against your own bills, not a national average. Upfront cost includes materials and any contractor; volunteer time is listed but not priced.
The arithmetic
- Payback (months)
- = upfront cost ÷ yearly savings × 12
- Five-year net
- = yearly savings × 5 − upfront cost
- No upfront cost
- = payback “immediate”
The waste check is a back-of-envelope estimate, not a plan. You enter your average monthly electric bill, your heating fuel and yearly heating spend, how often the building is used, and six yes/no questions about its condition. Each “yes” adds one measure, sized as a share of the relevant spend.
Those shares are planning assumptions, not measurements of your building. A real Payback Plan replaces all of them with your actual bills and rate plan.
The CO₂ line converts dollars to kilowatt-hours using the New York average electricity price[4] and EPA emission factors.[9] It never affects the dollar figures.
The formula
yearly spend = monthly electric × 12 + yearly heating
(electric heat: not added twice)
each fix = its share × the spend it affects
range = 10% to 20% of yearly spend
payback = upfront ÷ yearly saving × 12
Inputs above $50,000 a month (electric) or $600,000 a year (heating) are treated as typos and produce no result.
Assumptions and their sources
| Assumption | Value | Source |
|---|---|---|
| New York electricity price (for kWh and CO₂ only) | 29.45¢ per kWh | EIA Electric Power Monthly, Table 5.6.A (New York residential average, April 2026) |
| Illustrative waste range, doing nothing | 10% to 20% of total energy spend, inside the up to 30% ENERGY STAR cites for worship facilities | ENERGY STAR for Congregations (an average worship facility can save up to 30%) |
| Heating share of the bill, for electric heat | 35% of electric spend | Sources: to be added |
| Cooling share of the electric bill | 10% of electric spend | Sources: to be added |
| Thermostat schedules | 15% of heating + cooling (used a few days a week), 10% (used most days) | Sources: to be added |
| LED changeover | 12% of electric spend | Sources: to be added |
| Sealing drafts | 8% of heating spend | Sources: to be added |
| Boiler or furnace tune-up | 5% of heating spend (not for electric heat) | Sources: to be added |
| Smart power strips | 4% of electric spend, at most $200 a year | Sources: to be added |
| Old spare fridge | 900 kWh a year, never more than the electric bill | Sources: to be added |
| Upfront costs | Planning figures per measure, not quotes | Sources: to be added |
| CO₂ factors for electricity and gas | 0.8231 lb per kWh (U.S. average), 11.7 lb per therm of gas | EPA Greenhouse Gas Equivalencies Calculator: Calculations and References |
| CO₂ factor for heating oil | 6 lb per dollar of oil | Sources: to be added |
| Natural gas price (for CO₂ only) | $1.75 per therm | Sources: to be added |
| Tree equivalent | 132 lb CO₂ per young urban tree per year | EPA Greenhouse Gas Equivalencies Calculator: Calculations and References |
The specimen Payback Plan, and the drawing and figures on our home page, describe a fictional mid-size congregation in the Hudson Valley. Its numbers are internally consistent: twelve months of bills add up to $13,800, and five ranked actions add up to $2,140 a year.
Where the specimen relies on a figure we haven’t sourced yet, it says “specimen assumption” or “in this specimen.” Treat those as illustrations of the format, not claims about buildings in general.
[1]
New York Public Service Law § 76: Rates for religious bodies, New York State Senate
Cited for: Service used exclusively for religious purposes may qualify for residential-rate gas and electric service.
Checked 2026-07-16
[2]
FlexTech Program (PON 4192), NYSERDA
Cited for: NYSERDA cost-shares energy studies for commercial and institutional buildings, typically 50–75% of the study cost.
Checked 2026-07-16
[3]
NYS Clean Heat, NYSERDA and New York's investor-owned utilities
Cited for: Heat-pump rebates; since January 1, 2026 the residential track covers only 1–4 family homes, so congregations go through their utility's commercial track.
Checked 2026-07-16
[4]
Electric Power Monthly, Table 5.6.A: Average price of electricity by state, U.S. Energy Information Administration
Cited for: The New York electricity price the waste check uses to convert dollars to kilowatt-hours for its CO₂ line (data as of April 2026).
Checked 2026-10-16
[5]
ENERGY STAR for Congregations, U.S. EPA, ENERGY STAR
Cited for: An average worship facility can save up to 30 percent on energy.
Checked 2026-10-16
[6]
Commercial Buildings Energy Consumption Survey 2018, Table C4, U.S. Energy Information Administration
Cited for: Religious worship buildings spend an average of $9,000 a year on major fuels ($0.72 per square foot).
Checked 2026-10-16
[7]
How to create big opportunities to save energy for small businesses (Seth Nowak, 2016), American Council for an Energy-Efficient Economy (ACEEE)
Cited for: Small businesses have often been underserved by utility efficiency programs, facing a lack of staff, time, money, and awareness.
Checked 2026-10-16
[8]
Programmable Thermostats, Energy Saver (archived July 1, 2026), U.S. Department of Energy
Cited for: Turning a thermostat back 7°F to 10°F for 8 hours a day can save as much as 10% a year on heating and cooling.
Checked 2026-10-16
[9]
Greenhouse Gas Equivalencies Calculator: Calculations and References, U.S. EPA
Cited for: 0.0053 metric tons CO₂ per therm of natural gas; 0.060 metric tons CO₂ per urban tree per year (10-year growth average); U.S. average 823.1 lb CO₂ per MWh (eGRID 2022).
Checked 2026-10-16
[10]
eGRID2022 Summary Tables, Table 1: Subregion Output Emission Rates, U.S. EPA
Cited for: Upstate New York (NYUP) electricity: 274.6 lb CO₂ per MWh.
Checked 2026-10-16
Spot a number that’s wrong or out of date? Write to hello@lightkeeperproject.org and we’ll fix it.