Audit Duke Energy Florida Assumptions in a Solar Proposal

Verify the property and source period

Confirm that the current bill names Duke Energy Florida and that the service address matches the proposed installation. Use at least 12 consecutive months of kWh when available, with the start and end dates recorded. Mark missing bills, estimated readings, new occupancy and planned loads such as an EV, pool pump, heat-pump water heater or HVAC replacement.

Do not let an annual usage number appear without its source. A salesperson may summarize bills, but the homeowner should be able to reproduce the total. If weather, vacancy or a recent remodel makes the year atypical, show an alternate scenario rather than silently replacing the history with a preferred number. Keep account credentials private; a downloaded statement or redacted usage table is enough for comparison.

Separate energy production from bill value

The design model should state system capacity, equipment assumptions, roof planes, shade basis, annual production and degradation method. The utility model should state the Duke account period, the treatment of solar used in the home, the treatment of energy sent through the meter and the charges assumed to remain. One estimated production figure cannot substitute for all of those bill inputs.

Create two ledgers. The energy ledger tracks household use, modeled production, self-consumption, import and export in kWh. The money ledger tracks the solar payment or purchase path plus the remaining Duke bill. If the proposal cannot show how the energy ledger feeds the money ledger, treat the advertised monthly difference as unresolved—not as a guaranteed benefit.

Date every utility assumption

Duke’s September 2025 announcement described a 2026 bill change for a residential customer using 1,000 kWh and stated that rates can fluctuate during the year. [1] That public example is context, not a property tariff or a promise. Record the proposal’s source date, rate or rider label and the person responsible for updating it before contract signing if the project timeline changes.

Do not convert Duke’s example into a blanket escalation rate. If the proposal shows future utility inflation, request a second case with a different assumption and a case with no escalation. The purpose is not to make the return look good; it is to show how sensitive the comparison is to a variable no installer controls. Preserve negative or lower-savings outcomes when the inputs produce them.

Keep minimum and remaining charges in the comparison

Duke publishes an explanation of the Florida minimum bill. [2] Ask the proposal to identify customer, minimum or other continuing charges it leaves in the post-solar estimate. Solar offset is an energy comparison; it is not permission to erase the utility account from the budget. A battery also does not automatically remove those charges or change the tariff treatment of exports.

Compare the full written scope alongside the bill model: equipment, roof work, electrical work, permitting, interconnection, monitoring, warranties, service responsibilities and exclusions. A low first payment or a single savings percentage cannot replace the complete installed-price and payment-term review. Origin confirms property-specific pricing after verification and does not publish a generic cash price on this path.

Approve one reviewable version

Give the final proposal a version date and keep its usage file, production model, Duke assumptions, equipment schedule and payment terms together. Record every manual change and identify whether it affects system size, offset, remaining bill or total cost. When panels are added or removed, the modeled production and offset should recalculate rather than leaving the prior result in place.

Before signing, ask: which values came from Duke, which came from the roof model, which are homeowner choices and which are estimates? A reviewer should be able to answer without relying on a verbal presentation. Origin Direct can exchange that review for the homeowner’s address, bill and contact details while preserving its tracked path; it cannot guarantee future rates, five-year payback, bill elimination or utility approval.

Primary sources

1. Duke Energy Florida: 2026 Residential Bill Update

   Checked October 21, 2026. Duke announced 2026 changes for a stated 1,000-kWh residential example and noted that rates can change during the year. The example is not a forecast for a particular solar home.

2. Duke Energy Florida: Understanding the Minimum Bill

   Checked October 21, 2026. Duke explains its Florida minimum-bill structure. Confirm the current tariff and account-specific bill rather than assuming solar removes every utility charge.

3. Duke Energy: Track Energy Use

   Checked October 21, 2026. Duke describes account tools organized by bill cycle, week, day and hour. Availability and displayed intervals depend on the actual account and meter.

4. Florida Administrative Code Rule 25-6.065: Interconnection and Metering of Customer-Owned Renewable Generation

   Checked October 21, 2026. Florida Department of State identifies this as the latest final adopted version. Utility forms, tariffs and project-specific review still control the actual submission.

Planning examples and questions are Origin’s editorial guidance, not a property-specific diagnosis, engineering design, tax determination or promise of savings. Manufacturer and utility references do not imply an affiliation with Origin.

Related guidance

• Reconcile bill and monitoring records
• Review the production model
• Request a proposal comparison