How to interpret the calculators
The tools on BalconySolarCalculator.com are scenario calculators, not quotes, production guarantees, legal determinations, tax advice, or live data services. They combine user entries with fixed values stored in each page. Results can be useful for comparing scenarios, but they should be checked against a current electricity bill, equipment quote, site-specific solar model, official law, utility requirements, and qualified professional advice where appropriate.
No calculator retrieves a live utility tariff, product price, weather file, legislative database, or incentive database. A statewide average electricity price is not the same as the price on an individual bill.
Electricity-price data
The calculators contain a static table of state electricity-price inputs. Earlier page copy described the table as “real EIA electricity rates,” but the embedded values do not consistently reproduce one identifiable EIA monthly, year-to-date, or annual table. They are therefore documented as planning inputs and have not been changed in this review.
The previously displayed 17.65¢/kWh figure appears only in informational homepage copy and does not feed any calculation. It matches the EIA's preliminary U.S. residential average retail price for February 2026, a monthly value—not an annual national average. It was removed from the marketing copy to avoid that ambiguity.
EIA explains that its average retail electricity price is calculated from revenue divided by sales. It is not an individual customer's tariff. For authoritative comparisons, consult the EIA Electric Power Monthly national table, the EIA state residential table, and the EIA explanation of price data. Use the energy charge and applicable riders from your own bill when making a purchase decision.
Payback calculator
The main calculator estimates daily production as system kilowatts × the embedded state peak-sun-hours value × the selected orientation factor. It multiplies daily production by 30.4 days and a fixed 85% system factor to estimate monthly production. Estimated monthly savings are monthly production × the selected self-consumption factor × the embedded electricity price. Estimated payback is entered system cost divided by estimated monthly savings.
Orientation factors are 100% for south, 88% for southwest/southeast, 72% for east/west, 40% for north, and 80% for “not sure.” Self-consumption factors are 85% for mostly home, 65% for partly home, and 45% for away on most weekdays. These are simplified calculator assumptions, not universal measured values.
The system-cost slider and presets are user-input aids. They are not a national price range. The formerly displayed “18–36 months typical U.S. payback” was hard-coded marketing copy, not a calculated nationwide statistic. Payback depends on all of the inputs above.
Orientation calculator
The orientation tool uses a fixed 4.5 peak-sun-hours-per-day assumption, an 85% system factor, the entered electricity price, and direction factors of 100% south, 87% southwest/southeast, 72% east or west, 45% northwest/northeast, and 25% north. Its tilt table treats 30–35 degrees as 100% and ranges from 85% at 0 degrees to 70% at 90 degrees.
Those exact percentages are internal comparison assumptions. They are not copied from NREL and should not be treated as a location-specific forecast. NREL's PVWatts Calculator is the preferred authoritative tool for a location-specific estimate using address, azimuth, tilt, equipment, losses, and weather data.
Renter and homeowner comparison
The renter scenario uses 4.5 peak sun hours, an 80% orientation factor, an 85% system factor, the selected static state price, and the entered wattage and cost. Its long-term figures use fixed multipliers documented in the results.
The homeowner scenario assumes $2.80 per installed watt, 4.5 peak sun hours, an 80% system factor, flat electricity prices, no export compensation beyond the entered bill, no state incentives, 22 times annual savings for the 25-year figure, and a $4-per-watt home-value effect. These are internal scenario assumptions, not current national quotes, NREL benchmarks, incentive determinations, or appraisal guarantees.
The IRS states that the Section 25D Residential Clean Energy Credit is not available for property placed in service after December 31, 2025. See the IRS Residential Clean Energy Credit page and the IRS termination-date FAQ. Other credits and incentives have separate eligibility rules.
Battery calculator
The battery tool uses static state prices and sun hours, an 85% system factor, and fixed self-consumption pairs: 85%/97% for mostly home, 60%/92% for partly home, and 35%/88% for away. Battery capture is limited by selected capacity relative to modeled daily generation. Selecting a time-of-use plan applies a fixed 15% savings boost.
The 512Wh/$300, 1,024Wh/$550, and 2,048Wh/$950 options are illustrative capacity and price presets. They are not live product prices or recommendations. The model does not reproduce an actual tariff or fully model usable capacity, charge/discharge losses, standby consumption, degradation, cycling limits, warranty, or backup operation.
Legal-status and wait-or-buy tools
The legal classifications, effective-date notes, wattage limits, utility notes, and readiness scores form a fixed September 2026 research snapshot. The wait-or-buy result adds points based on that status, a static electricity-price value, housing selection, urgency, and bill-pain selection. Its score is a planning heuristic, not a legal or financial finding.
Legislative passage, enactment, effective date, implementing rules, safety-standard availability, code compliance, utility procedures, and property rights are different issues. A status can become stale quickly. California SB 868, for example, had later action after the embedded September snapshot; the dataset was not changed because this phase did not authorize calculator data or scoring changes.
Official sources reviewed include:
- Utah HB 340 enrolled text
- Maine LD 1730 status
- Virginia HB 395 chapter text
- Colorado HB26-1007 status
- Maryland HB 1532 status
- New Hampshire SB 540 status
- Connecticut HB 5340 status
- Vermont S.202 status
- New Jersey S2368 status
- New York S8512C status
- California SB 868 status
Always open the current official source and confirm the law, effective date, utility procedure, code, equipment requirements, and property restrictions that apply to the installation address.
Solar equipment life and output
The site does not guarantee “free electricity” after modeled payback. DOE reports that photovoltaic systems can have operational lifespans measured in decades, while actual output, maintenance, inverter or component replacement, damage, and end-of-life timing vary. See DOE's End-of-Life Management for Solar Photovoltaics and PV life-cycle guidance.
Update policy and unresolved limitations
Factual copy and source labels were reviewed October 6, 2026. The calculator datasets and formulas were deliberately left unchanged. The static state electricity values do not map cleanly to one cited EIA table, and the legal snapshot contains at least one status that changed after its review date. Those datasets require a separately approved, versioned update with regression testing.
Product prices, equipment availability, state incentives, community-solar contract terms, and utility tariffs were removed as general factual claims where no current authoritative source supported them. Users should verify those items directly with the responsible source.
Last reviewed October 6, 2026.