Home energy and appliances sources and dates
Where the starting numbers for the calculators in this group come from, and the date we checked each one. They are examples, not quotes.
Sources by Calculator
Back to all sources and dates. Each table lists a calculator's starting numbers, source links and check dates.
Solar panel payback
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Solar irradiation and monthly production | Site-specific (PVWatts v8) | NLR (formerly NREL) PVWatts v8 API | 2026-10-16 |
| Residential electricity rates | Site-specific ($0.18 to $0.28 / kWh) | U.S. Energy Information Administration (EIA) Form 861 / OpenEI Utility Rate Database | 2026-10-08 |
| Rooftop solar installation cost | $4.00 / Watt DC ($32,000 for 8 kW) | Lawrence Berkeley National Laboratory (LBNL), Distributed Solar and Storage 2025 Data Update | 2026-10-16 |
| Federal Section 25D Clean Energy Credit | 0% default | IRS FAQs on the changes to sections 25C, 25D and others under Public Law 119-21 | 2026-10-16 |
| Business solar credit (Section 48E) | 0% in the home example; 30% in the commercial example (a historical workbook figure) | IRS draft instructions for Form 3468 (2026) | 2026-10-16 |
| Business depreciation (Business tax view) | 5-year MACRS, half-year rule, 0% bonus | IRS cost recovery for qualified clean energy facilities, property and technology | 2026-10-16 |
| Solar panel degradation rate | 0.50% / year | NLR Annual Technology Baseline (ATB) | 2026-10-16 |
| Address geocoding | Street address to lat/lon | U.S. Census Bureau Geocoding Services API | 2026-10-08 |
Heat pump vs fossil fuel heating
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Heating oil price | $6.04 / gal | U.S. EIA Heating Oil and Propane Update | 2026-10-05 |
| Propane price | $2.64 / gal | U.S. EIA weekly residential propane price | 2026-10-16 |
| Natural gas price | $1.60 / therm | U.S. EIA Natural Gas Prices | 2026-10-08 |
| Residential electricity price | $0.18 / kWh | U.S. EIA Electric Power Monthly, Table 5.6.A | 2026-10-16 |
| Heating oil energy content | 138,500 BTU / gal | U.S. EIA Energy Units & Conversions | 2026-10-12 |
| Propane energy content | 91,500 BTU / gal | U.S. EIA Energy Units & Conversions | 2026-10-12 |
| Natural gas energy content | 100,000 BTU / therm | U.S. EIA Energy Units & Conversions | 2026-10-12 |
| Electricity energy content | 3,412 BTU / kWh | U.S. EIA Energy Units & Conversions | 2026-10-12 |
| Existing oil boiler AFUE | 83% | U.S. Department of Energy / Energy Star | 2026-10-12 |
| Existing propane boiler/furnace AFUE | 82% | U.S. Department of Energy | 2026-10-12 |
| Existing natural gas AFUE | 82% | U.S. Department of Energy | 2026-10-12 |
| Heat pump seasonal COP | 3.0 | NEEP Cold-Climate Air-Source Heat Pump List | 2026-10-12 |
| Heat pump installed cost | $18,000 | NYSERDA Clean Heat Market Study & Installer Survey | 2026-10-12 |
| Avoided like-for-like replacement | $8,500 | NYSERDA / HomeAdvisor HVAC Cost Guide | 2026-10-12 |
| Federal 25C tax credit | $0 (ended) | IRS FAQs on the One Big Beautiful Bill credit changes | 2026-10-16 |
| DOE Home Energy Rebates (HEAR, HOMES) | $0 default | NC DEQ summary of DOE Program Notices 26-1 and 26-2 | 2026-10-16 |
| NY Clean Heat rebates | $0 default (up to $8,000+) | NYS Clean Heat Program | 2026-10-12 |
| NYSERDA EmPower+ | $0 default | NYSERDA EmPower+ Program | 2026-10-12 |
Home battery backup and solar storage
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Usable battery capacity | 13.5 kWh | Tesla Powerwall 3 Datasheet | 2026-10-12 |
| Installed system cost | $14,000 | EnergySage Home Battery Cost Survey & NREL U.S. Solar Photovoltaic and Energy Storage Cost Benchmark | 2026-10-12 |
| Round-trip efficiency | 90% | Tesla Powerwall 3 Technical Specs & Sandia National Laboratories Energy Storage Systems | 2026-10-12 |
| Retained capacity warranty | 70% at 10 years | Tesla Powerwall Warranty & Enphase Warranty | 2026-10-12 |
| Time-of-use rate example (NY) | Peak: $0.35/kWh; Off-peak: $0.12/kWh (the example uses a time-of-use plan) | Central Hudson Residential Time-of-Use Rate (SC 6) & ConEd SC 1 Rate III | 2026-10-16 |
| Annual TOU cycles | 300 cycles | DOE OE Energy Storage Database | 2026-10-12 |
| Solar export credit rate | $0.18 (1:1 Net Metering) or $0.08-$0.10 (VDER/Avoided Cost) | NYSERDA Value of Distributed Energy Resources (VDER) & NYS DPS Net Metering Rules | 2026-10-08 |
| Grid outage duration (reliability) | 220 minutes/yr in New York (incl. major events) | EIA Form 861 State Electric Reliability Indices (SAIDI) | 2026-10-16 |
| Value of backup power | $0 / hour | LBNL Interruption Cost Estimate (ICE) Calculator | 2026-10-12 |
| Incentives (Federal & State / Utility) | $0 default | NYSERDA Energy Storage Program & IRS FAQs on the One Big Beautiful Bill credit changes | 2026-10-16 |
Appliance electricity running cost
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Electricity price | $0.18 / kWh | EIA Electric Power Monthly Table 5.6.A | 2026-10-08 |
| Space heater power | 1,500 W | DOE Energy Saver: Estimating Appliance Energy Use | 2026-10-08 |
| Window air conditioner | 1,000 W (8,000 BTU) | ENERGY STAR Room Air Conditioners | 2026-10-12 |
| Central air conditioning | 3,500 W (3 ton) | DOE Energy Saver Central Air Conditioning | 2026-10-12 |
| Dehumidifier | 450 W | ENERGY STAR Dehumidifiers | 2026-10-12 |
| Hot tub | 1,500 W avg | California Energy Commission Title 20 Appliance Efficiency | 2026-10-12 |
| Refrigerator | 450 kWh/year | FTC EnergyGuide / ENERGY STAR Certified Refrigerators | 2026-10-12 |
| Chest freezer | 250 kWh/year | FTC EnergyGuide / ENERGY STAR | 2026-10-12 |
| Electric water heater | 4,500 W | DOE Energy Saver Water Heating | 2026-10-12 |
| Electric clothes dryer | 3,000 W | ENERGY STAR Clothes Dryers | 2026-10-12 |
| Dishwasher | 270 kWh/year | FTC EnergyGuide / ENERGY STAR | 2026-10-12 |
| Electric oven / range | 2,500 W | DOE Energy Saver | 2026-10-12 |
| Microwave oven | 1,000 W | DOE Energy Saver | 2026-10-12 |
| Desktop PC with monitor | 150 W | Lawrence Berkeley National Laboratory Standby Power | 2026-10-12 |
| Laptop computer | 50 W | Lawrence Berkeley National Laboratory | 2026-10-12 |
| Video game console | 180 W | Natural Resources Defense Council (NRDC) Console Energy Study | 2026-10-12 |
| Television (55" 4K LED) | 80 W | ENERGY STAR Televisions | 2026-10-12 |
| Wi-Fi router / modem | 12 W | LBNL Standby Power Summary | 2026-10-12 |
| LED light bulb | 9 W | ENERGY STAR Certified Light Bulbs | 2026-10-12 |
| Incandescent light bulb | 60 W | DOE Energy Saver Lighting | 2026-10-12 |
| Sump pump | 800 W | Goulds / Wayne Sump Pump Technical Datasheets | 2026-10-12 |
| Well water pump | 1,200 W | Franklin Electric Submersible Motor Datasheets | 2026-10-12 |
| EV charger Level 1 | 1,400 W | DOE Alternative Fuels Data Center | 2026-10-12 |
| EV charger Level 2 | 7,200 W | DOE Alternative Fuels Data Center | 2026-10-12 |
| Electric blanket | 100 W | Consumer Reports Heating Pad & Blanket Testing | 2026-10-12 |
| Swimming pool pump | 1,500 W | ENERGY STAR Pool Pumps | 2026-10-12 |
| Box / ceiling fan | 60 W | DOE Energy Saver Fans | 2026-10-12 |
Heat pump water heater payback
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Equipment efficiencies (UEF) | 0.92 electric, 0.62 gas, 3.50 HPWH | Energy Star Water Heater Program | 2026-10-08 |
| Electricity price | $0.18/kWh | US Energy Information Administration (EIA) Electric Power Monthly, Table 5.6.A | 2026-10-16 |
| Natural gas price | $1.60/therm | US Energy Information Administration (EIA) Natural Gas Prices | 2026-10-16 |
| Propane price | $2.64/gal | US Energy Information Administration (EIA) weekly residential propane price | 2026-10-16 |
| State tax credit | 0% (no cap applied) | IRS Energy Credit Termination FAQ | 2026-10-16 |
| Utility rebate | $0 (illustrative $800 example) | DSIRE Database of State Incentives for Renewables and Efficiency | 2026-10-08 |
Attic insulation and air sealing payback
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Expected heating and cooling bill reduction | 15% | EPA Energy Star Seal and Insulate Methodology | 2026-10-08 |
| Recommended attic insulation level | R-49 to R-60 | U.S. Department of Energy Insulation Guidelines | 2026-10-08 |
| Turnkey project installed cost | $2,400 ($2.00 / sq ft on 1,200 sq ft) | DOE / HomeAdvisor Attic Insulation Cost Guide | 2026-10-08 |
| Federal Section 25C tax credit | None; state tax credit $0 | IRS FAQs on the 2025 changes to 25C, 25D and other credits | 2026-10-16 |
| State and utility weatherization rebates | $0 default ($500 to $1,500 typical) | DOE Home Energy Rebates (HOMES and HEAR); NC DEQ summary of DOE Program Notices 26-1 and 26-2 | 2026-10-16 |
Appliance repair vs replace
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Appliance electricity consumption | 700 kWh/yr existing vs 400 kWh/yr new | U.S. DOE and EPA Energy Star Appliance Benchmarks | 2026-10-12 |
| Appliance service life and 50% Rule | 12 years new life; 4 years repair life | Consumer Reports Appliance Lifespan Survey | 2026-10-12 |
| Residential electricity rate | $0.18 / kWh | U.S. EIA Electric Power Monthly Table 5.6.A | 2026-10-08 |
| Replacement appliance purchase price | $1,100 | Bureau of Labor Statistics CPI Major Appliances | 2026-10-12 |
| Repair quote benchmark | $300 | Consumer Reports Appliance Repair Cost Guide | 2026-10-12 |
Smart thermostat payback
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Smart thermostat device cost | $220 | ENERGY STAR Smart Thermostats Product Finder | 2026-10-13 |
| Utility marketplace rebate | $75 | ENERGY STAR Rebate Finder | 2026-10-13 |
| Annual heating and cooling bill | $1,800/yr | U.S. Energy Information Administration Residential Energy Consumption Survey | 2026-10-13 |
| Certified HVAC bill savings | 8% | ENERGY STAR Smart Thermostats Savings Methodology | 2026-10-13 |
| Demand-response annual credit | $35/yr | U.S. Department of Energy Grid-Interactive Efficient Buildings | 2026-10-13 |
Replacement windows payback
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Installed cost per window | $850 (12 windows = $10,200) | Journal of Light Construction Cost vs. Value Report | 2026-10-13 |
| Tax credit or rebate | $0 | Internal Revenue Service Energy Efficient Home Improvement Credit | 2026-10-16 |
| Annual heating and cooling bill | $2,200/yr | U.S. Energy Information Administration Residential Energy Consumption Survey | 2026-10-13 |
| Heating and cooling bill savings | 12% | ENERGY STAR Certified Windows, Doors, and Skylights | 2026-10-13 |
| Resale value recouped | 67% | Journal of Light Construction Cost vs. Value Report | 2026-10-13 |
Adding a battery to existing solar
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Residential AC-coupled battery retrofit installed cost and usable capacity | $13,500 installed cost for 13.5 kWh nominal (12.2 kWh usable cycled capacity) | National Renewable Energy Laboratory U.S. Solar Photovoltaic System and Energy Storage Cost Benchmarks | 2026-04-01 |
| Round-trip efficiency and annual lithium-iron-phosphate (LFP) capacity degradation | 90% round-trip efficiency, 2.0%/yr capacity fade over 15-year warranty | Lawrence Berkeley National Laboratory Tracking the Sun and Residential Storage Analysis | 2026-04-01 |
| Peak time-of-use (TOU) retail electricity rate, solar export credit, and rate escalation | $0.38/kWh evening peak rate vs $0.08/kWh net billing export credit, 3.5%/yr utility escalation | U.S. Energy Information Administration Electric Power Monthly and Net Billing Tariff Benchmarks | 2026-04-01 |
| State/utility battery rebates, Virtual Power Plant (VPP) grid-event payouts, and outage backup value | $0 rebate, $0/yr VPP payout, $0/yr backup value (enter yours if you qualify) | Lawrence Berkeley National Laboratory Behind-the-Meter Battery Storage and VPP Valuation | 2026-10-16 |
Metal vs asphalt roof
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Roof size | 30 squares (3,000 sq ft of roof surface; second-hand, confirm) | Zonda and JLC Cost vs. Value 2025 | 2026-10-17 |
| Shingle price per square, installed | $1,060 (report job cost $31,871 / 30 = $1,062.37, rounded; second-hand, confirm) | Zonda and JLC Cost vs. Value 2025 | 2026-10-17 |
| Metal price per square, installed | $1,730 (report job cost $51,865 / 30 = $1,728.83, rounded; second-hand, confirm; the report does not say it is standing seam) | Zonda and JLC Cost vs. Value 2025. Context only, not the origin of the number: HomeAdvisor metal roof cost guide | 2026-10-17 |
| Tear-off and disposal, extra | $0 per square (the report job cost includes tear-off; second-hand, confirm) | Zonda and JLC Cost vs. Value 2025 | 2026-10-17 |
| Share of a new shingle roof a buyer repays | 68% (report: $21,501 resale value on $31,871 cost, which is 67.5% by our division; second-hand, confirm) | Zonda and JLC Cost vs. Value 2025 | 2026-10-17 |
| Share of a new metal roof a buyer repays | 50% (report: $25,972 resale value on $51,865 cost; second-hand, confirm) | Zonda and JLC Cost vs. Value 2025 | 2026-10-17 |
| Shingle roof life | 25 years (typical, edit this) | National Roofing Contractors Association figures in a USDA Forest Service slide | 2026-10-17 |
| Metal roof life | 50 years (typical, edit this) | National Roofing Contractors Association figures in a USDA Forest Service slide and HomeAdvisor metal roof cost guide | 2026-10-17 |
| Years compared if you keep the house | 50 years (typical, edit this) | Our own round choice. Context only, not the origin of the number: National Roofing Contractors Association figures in a USDA Forest Service slide | 2026-10-17 |
| Years you plan to stay | 15 years (typical, edit this) | Our own round choice, no source. Context only, not the origin of the number: Zonda and JLC Cost vs. Value 2025 | 2026-10-17 |
| Yearly growth in roof prices and in the value of savings | 3% (typical, edit this) | Our own round choice. Context only, not the origin of the number: Bureau of Labor Statistics Consumer Price Index | 2026-10-17 |
| Discount rate | 5% a year (typical, edit this) | Our own round choice. Context only, not the origin of the number: U.S. Treasury interest rate data | 2026-10-17 |
| Yearly cooling bill and cooling saving from a light metal roof | $600 a year and 10% (typical, edit this; the study figures are second-hand, confirm), so $60 a year | Context only, not the origin of the number: Florida Solar Energy Center report FSEC-CR-1220-00 | 2026-10-17 |
| Insurance discount for a metal roof | $0 a year (no source supports a discount; enter only one your insurer quoted) | Context only, not the origin of the number: Louisiana Department of Insurance report on the FORTIFIED roof discount | 2026-10-17 |
Standby generator vs home battery
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Outage hours a year | 3.7 (New York), 10.2 (U.S.) | EIA Electric Power Annual, table 11.3 (2024, all events) | 2026-10-17 |
| Hours in one outage | 4.0 (New York), 6.7 (U.S.) | EIA Electric Power Annual, table 11.3 (2024, all events) | 2026-10-17 |
| Power to keep on | 1.5 kW (typical) | EIA FAQ on home electricity use | 2026-10-17 |
| Cost of an hour without power | $10 (typical) | LBNL Interruption Cost Estimate Calculator, as shown in a CPUC slide deck (2021-05-12) | 2026-10-17 |
| Years to compare | 15 years | typical, no source | 2026-10-17 |
| Yearly price rise | 2% a year | typical, no source | 2026-10-17 |
| Generator with installation | $12,700 | Consumer Reports, 5 Best Whole-House Generators of 2026 (updated 2026-07-28) | 2026-10-17 |
| Generator rebate | $0 | typical, no source | 2026-10-17 |
| Generator service and parts | $250 a year (typical) | Generac owner's manual, 9 kW to 22 kW air-cooled | 2026-10-17 |
| Generator life | 20 years (typical) | Generac 22 kW standby generator page | 2026-10-17 |
| Generator power | 21 kW | Generac 22 kW standby generator page | 2026-10-17 |
| Gas used at half and full load | 221 and 311 ft³ an hour | Generac 22 kW standby generator page | 2026-10-17 |
| Weekly test run | 5 minutes | Generac owner's manual, 9 kW to 22 kW air-cooled | 2026-10-17 |
| Natural gas price | $17.58 per 1,000 ft³ (New York), $15.34 (U.S.) | EIA residential natural gas price, New York; EIA residential natural gas price, U.S. | 2026-10-17 |
| Battery with installation | $14,000 | typical, no source | 2026-10-17 |
| Battery rebate or tax credit | $0 | IRS FAQs on Public Law 119-21 | 2026-10-17 |
| Battery energy and power | 13.5 kWh and 11.5 kW | Tesla Powerwall 3 datasheet; LBNL, U.S. Distributed Solar and Storage, 2026 Data Update | 2026-10-17 |
| Battery life | 15 years (typical) | Tesla Powerwall 3 datasheet | 2026-10-17 |
| Share kept full for outages | 100% | typical, no source | 2026-10-17 |
| Round-trip efficiency | 90% (typical) | Tesla Powerwall 3 datasheet | 2026-10-17 |
| Battery upkeep | $0 a year | typical, no source | 2026-10-17 |
| Time-of-use prices and discharges | $0.35 peak, $0.12 off-peak, 300 a year | typical, no source | 2026-10-17 |
| Price the grid charges you | $0.20 per kWh | EIA New York electricity profile | 2026-10-17 |
| Credit for exported solar | $0.08 per kWh | typical, no source | 2026-10-17 |
Pellet or wood stove vs heating oil
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Heating oil price, New York | $6.335 a gallon, week ending 2026-10-12, before taxes (read directly) | EIA weekly New York heating oil | 2026-10-17 |
| Oil price a year earlier, New York | $3.837 a gallon (derived: $6.335 less EIA's $2.498 yearly rise) | EIA Heating Oil and Propane Update | 2026-10-17 |
| Heating oil energy content | 138,500 Btu a gallon (read directly) | EIA Energy Units and Conversions | 2026-10-17 |
| Oil furnace or boiler efficiency | 83%, federal minimum for a new oil furnace (confirm) | 10 CFR 430.32(e), eCFR | 2026-10-17 |
| Oil used for heat and the share replaced | 800 gallons a year and 50% (typical, edit this); Northeast average 460 gallons | EIA RECS 2020, Table CE4.7, Alliance for Green Heat | 2026-10-17 |
| New York residential electricity | $0.29 a kWh (29.38 cents, January to July 2026) | EIA Electric Power Monthly, Table 5.6 | 2026-10-17 |
| Pellet price | $380 a ton (typical, edit this; no New York price could be read) | Heller's and Northeast Pellets price lists; NYSERDA survey not opened | 2026-10-17 |
| Cordwood price | $350 a full seasoned cord (typical, edit this) | Fixr, wood stove cost | 2026-10-17 |
| Pellet heat content | 16.5 million Btu a ton, 8,250 Btu a pound (second-hand) | Maryland Extension FS-937, quoting the Pellet Fuels Institute | 2026-10-17 |
| Cordwood heat content | 22 million Btu a cord, mixed hardwood (typical, edit this) | Cornell Cooperative Extension, 2014 | 2026-10-17 |
| Stove efficiency | 70% for pellets, 65% for wood (typical, edit this; low end of tests) | Alliance for Green Heat, wood stoves, EPA Burn Wise | 2026-10-17 |
| Stove installed cost and yearly upkeep | $3,000 pellet, $4,000 wood with chimney, $200 a year (typical, edit this) | Fixr | 2026-10-17 |
| Stove electricity | 2.5 kWh a day (typical, edit this); cordwood 0 | PICKHVAC, 2025-06-03 | 2026-10-17 |
| Federal credit for biomass stoves | $0 (ended after 2025-12-31; confirm) | IRS, home improvement credit | 2026-10-17 |
| New York stove incentive | $0 (confirm; last known $1,500 in 2020, unverified, from search snippet) | Alliance for Green Heat, New York, second-hand; NYSERDA Renewable Heat NY, EmPower+ not opened | 2026-10-17 |
Tankless vs tank water heater
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| DOE efficiency range | 24% to 34% more efficient at 41 gallons a day or less, 8% to 14% at about 86 (second-hand, from a 2012 copy; DOE's live page did not load on 2026-10-18) | InspectAPedia copy of DOE page, 2012-05-02; DOE Energy Saver pages unverified (HTTP 404 on 2026-10-18) | 2026-10-18 |
| Hot water use and the Minnesota study | 48 gallons a day (typical, edit this; Minnesota study: 24, 48 and 54 by household size, second-hand); its 37% less energy and 20 to 40 year paybacks (2008 to 2010, CEE page, official) are shown, not used in the math | ACEEE 2012 paper, second-hand; CEE project page | 2026-10-18 |
| Tank installed price | $1,376 gas or propane, $902 electric (DOE averages; official) | 89 FR 105188; 89 FR 37778 | 2026-10-18 |
| Tankless installed price | $2,282 gas or propane basic, $2,499 condensing (DOE averages, 2023 dollars, from a withdrawn rule; official); $1,500 electric (typical, edit this; no DOE figure) | 89 FR 105188; withdrawal, 90 FR 21390 | 2026-10-18 |
| Extra work (electrical, venting, gas line) | $1,375 electrical (typical, edit this; middle of DOE's $750 to $2,000); $0 venting and $0 gas line (typical, edit this; DOE's average already assumes new venting, and no gas line price was found) | 89 FR 105188; maker datasheet, Stiebel Eltron rev. 6.2025; CEE slides | 2026-10-18 |
| Efficiency (UEF) | Tank 0.58 gas or propane, 0.92 electric (rounded federal minimums); tankless 0.81 gas or propane (federal minimum), 0.97 electric (typical, edit this) | 10 CFR 430.32; ENERGY STAR | 2026-10-18 |
| Heater lives | 13 and 20 years (typical, edit this; DOE says 10 to 15 and 20 or more) | DOE text, 2012 copy (second-hand); 89 FR 37778 | 2026-10-18 |
| Federal credit | $0 (ended after 2025-12-31; confirm) | IRS | 2026-10-18 |
| Utility and state rebates | $0 (unverified; confirm with your utility) | NYSERDA not opened (HTTP 403) | 2026-10-18 |
| Electric tank rule from 2029 | UEF 2.30 for plain electric tanks from 2029-05-06 (as published; confirm) | 10 CFR 430.32(d)(2) | 2026-10-18 |
| Electricity price | $0.25 a kWh, New York, as of 2026-10-08; U.S. $0.18 (shared state prices, EIA based) | EIA Electric Power Monthly | 2026-10-08 |
| Natural gas price | $1.78 a therm, New York, as of 2026-10-08; U.S. $1.60 (shared state prices, EIA based) | EIA residential gas prices | 2026-10-08 |
| Propane price | $3.28 a gallon, New York, as of 2026-10-08; U.S. $2.64 (shared state prices, EIA based) | EIA residential propane prices | 2026-10-08 |
Mini-split vs window units vs central air
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Electricity price, New York | $0.29 a kWh: January to July 2026 New York average, 29.38 cents, rounded (read directly) | EIA Electric Power Monthly, Table 5.6.B | 2026-10-18 |
| Electricity price rise | 3% a year (typical, edit this); not a forecast: New York rose 13.0% from 2025 to 2026, year to date (derived) | EIA Electric Power Monthly, Table 5.6.B | 2026-10-18 |
| Cooling hours a summer | 358 hours, Albany (read directly); seven New York cities run 201 to 602; includes typical attic duct losses | NY Technical Resource Manual v13, Appendix G | 2026-10-18 |
| Cooling capacity | 20 Btu an hour for each sq ft (derived from the sizing chart, read directly) | ENERGY STAR room air conditioner sizing chart | 2026-10-18 |
| Window unit price | $300 a unit (typical, edit this); guides $150 to $600 or more (read directly); retailer listings about $176 to $430 (prices only) | Liberty Home Guard article, 2026-10-07; a home-improvement retailer search page (no links kept) | 2026-10-18 |
| Window unit rating, CEER | 13.7, the federal minimum for new 6,000 to 7,900 Btu/h units made on or after 2026-05-26 (read directly); older units 9 to 11 (second-hand) | 10 CFR 430.32(b), eCFR | 2026-10-18 |
| Mini-split price, installed | $4,000 for the first unit and $3,000 for each added one (typical, edit this); guides $1,500 to $5,000 for one zone (read directly) | Liberty Home Guard article, 2026-10-07; Filterbuy and hvacprojectcost.com pages (second-hand; no links kept) | 2026-10-18 |
| Mini-split rating, SEER2 | 20 (typical, edit this); guides say 18 to 30 (read directly); DOE's 15.2 to 35 is unverified (search snippet), not used | Liberty Home Guard article, 2026-10-07; DOE page: not opened (404), unverified | 2026-10-18 |
| Mini-split field estimate (what-if only) | c + d x SEER2: c 7.83, d 0.493 (one indoor unit); c 12.20, d 0.085 (several) (read directly); stress line only | NY Technical Resource Manual v13, air-source heat pump measure, page 197 | 2026-10-18 |
| Central air price, installed | $7,000 on existing ducts (typical, edit this); guides $4,000 to $9,000 (read directly), $5,800 to $14,400 (second-hand) | Liberty Home Guard article, 2026-10-07; Fixr page, 2025-08-29 (second-hand; no links kept) | 2026-10-18 |
| New ducts price | $8,000, paid once (typical, edit this); guides $3,600 to $9,500 (second-hand), $10,000 to $25,000 with central air (read directly) | Fixr, hvacprojectcost.com (second-hand); Liberty Home Guard article, 2026-10-07 (no links kept) | 2026-10-18 |
| Central air rating, SEER2 | 15 (typical, edit this); guides 13 to 16 (read directly); legal minimum for a new split system in New York 13.4 (read directly) | 10 CFR 430.32(c), eCFR; Liberty Home Guard article, 2026-10-07 | 2026-10-18 |
| Upkeep a year | $100 each for mini-split and central air, $0 for window units (typical, edit this); tune-ups $75 to $200 (second-hand) | Liberty Home Guard article, 2026-10-07; PickHVAC, 2025-06-27 (second-hand; no links kept) | 2026-10-18 |
| Equipment life | Window units 10 and central air 15 (read directly); mini-split 15 (typical, edit this); DOE's own lifespan statements: not opened (404), unverified | NY Technical Resource Manual v13, Appendix M, Table M-2 | 2026-10-18 |
| Federal credit for heat pumps and air conditioners | $0: none for equipment placed in service after 2025-12-31 (read directly); confirm | IRS, energy efficient home improvement credit | 2026-10-18 |
| Mini-split rebate in New York | $0 (confirm); no amount verified: the official page, undated, says $100 to $400 or $2,000 to $3,000 on average; a second-hand page says more | NYS Clean Heat, tax credits page; NYSERDA pages: not opened (403), unverified | 2026-10-18 |
| Rebates on window units | $0 (unverified; nothing could be read); enter the price after any rebate | Con Edison rebate page: its list needs a script, so no text could be read | 2026-10-18 |
Furnace, boiler or AC: repair or replace
| Assumption / Input | Starting value | Source | Checked |
|---|---|---|---|
| Repair quote | $1,000 (typical, edit this). Ranges: furnace $349 to $650, boiler $150 to $750, central AC $150 to $2,000 (second-hand) | Fixr repair guides, 2025-08-29 to 2026-01-29 (opened) | 2026-10-18 |
| New system, installed | $6,000 gas furnace, $6,500 oil furnace, $7,000 gas boiler, $7,500 oil boiler, $6,900 central AC (typical, edit this; second-hand; no New York price found) | Fixr guides, 2025-01-31 to 2026-01-28; HVACBase, 2026-10-15 (opened) | 2026-10-18 |
| Life of the new system | 20 years (18 for central AC), typical, edit this. DOE modeled averages: gas furnaces 21.5, boilers 24.6, central AC 21.2. Guides say 10 to 25 (second-hand) | DOE rules (opened; AC rule via govinfo.gov, federalregister.gov did not open: unverified); Fixr, CBS (second-hand) | 2026-10-18 |
| Years the repair lasts, a second repair, and the yearly price rise | 5 years; no second repair; 3% a year (all typical, edit this; the 3% is not a forecast) | None found (searched 2026-10-18) | 2026-10-18 |
| Old unit's rating (when left blank) | Blank: the federal minimum for the year made (78 to 86%; AC 10 to 14 SEER), a floor. Old SEER x 0.95 = SEER2 (rule of thumb; second-hand) | 10 CFR 430.32, eCFR 2026-10-01 (opened); HVACBase for 0.95 (opened) | 2026-10-18 |
| New unit's rating | 95% gas furnace, 87% oil furnace, 90% gas boiler, 87% oil boiler, 15.2 SEER2 AC (typical, edit this; Energy Star levels are in the hints) | Energy Star criteria (opened, undated) | 2026-10-18 |
| Yearly fuel or power use | 530 therms, 500 gallons or 2,800 kWh a year (typical, edit this; U.S. single-family averages) | EIA survey 2020, tables CE4.6 and CE4.7 (opened) | 2026-10-18 |
| Fuel and power prices | U.S.: gas $1.60 a therm, oil $6.04 a gallon, power $0.18 a kWh. New York: $1.78, $6.08, $0.25. Dates are in the hints | EIA, via the site's shared price files | 2026-10-08 |
| Rebates and credits | $0. The federal credit ended after 2025-12-31 (confirm). New York: unverified, NYSERDA pages returned 403 | IRS (opened); NYS Clean Heat (opened); NYSERDA not opened | 2026-10-18 |
| Rules of thumb (notes only, never the answer) | Notes only: $5,000 rule, half-price rule, Energy Star age flag (15 years, AC 10) | CBS News, DOE guide 2011, Energy Star (opened) | 2026-10-18 |
| Safety, oil tank and R-22 links | Links only, no advice of our own | CPSC, EPA, NY DHSES, CDC, NY DEC, EPA R-22 FAQ (opened) | 2026-10-18 |
| New York boilers: age and efficiency | 33 years, 73.19% (2017 trade average; second-hand, interested party). Not defaults | Oil and Energy, 2017 (opened) | 2026-10-18 |
| Pages that could not be opened | Unverified: NYSERDA (403), energy.gov Energy Saver (404), Energy Star landing pages (404), federalregister.gov (redirected) | Nothing from these is used | 2026-10-18 |