Costs, payback and incentives
How InverseAudit prices each measure, which utility incentives it applies, and how payback and SIR are calculated.
For: AnalyzerWhere: Dataset › Retrofit Costs, Dataset › Utility Incentives and the Energy Audit page
On this page
Retrofit costs
The cost of each measure comes from a retrofit costs table, priced per unit (for example per square foot of roof). Open Dataset › Retrofit Costs in the left menu to see it.
When you click Update, the audit prices the measures with your own table for the building’s audit year and state if you have one, and otherwise the Standard dataset. The standard dataset can’t be edited. Calculate only recalculates the savings; the costs, the number of measures and the net project budget are recalculated when you click Update.
| Column | Meaning |
|---|---|
| Life Expectancy | Years the measure lasts. Used for the SIR. |
| Bare Material | Material cost per unit, without overhead and profit |
| Bare Labor | Labor cost per unit, without overhead and profit |
| Bare Total Costs | Bare material + bare labor |
| Multiplier | Overhead and profit markup. A blank multiplier counts as 1. |
| Total O&P | Bare Total Costs × Multiplier, the cost per unit used in the audit |
Create your own costs table
- On Retrofit Costs, click NEW COSTS TABLE.
- Choose the audit year and state the table is for.
- Choose Copy from a standard dataset, Copy from your dataset or Create an empty dataset, and click Create Table.
- Edit the costs, then click Save changes. The bare total and Total O&P columns update when the page reloads.
Each year and state can have one table. Make the table for the building’s own state, because the audit only picks up a table whose state matches the building.
Change the cost of one measure
On the Recommendations tab of the report, the analyzer can click a measure’s Retrofit Costs or Utility Incentives value, enter a new amount and click Update. A retrofit cost you type in is kept the next time you update the report. All other costs are priced again from the current retrofit costs table.
Utility incentives
Open Dataset › Utility Incentives and choose the Utility, Service Rate and Audit Year to see the incentive programs InverseAudit knows about. This page is maintained by InverseAudit. If your utility’s programs are missing or out of date, click Contact Us.
- Performance-based incentives pay per kWh and per kW saved. These are the ones the audit calculates.
- Retrofit-based incentives are listed with their program name and website for reference. They aren’t added to the audit’s totals.
- The Whole building tab holds programs that pay for the whole building’s savings or per square foot.
Incentives need a utility rate. With an average rate, the Net project budget card says that incentives can’t be applied. See Rates.
In the Energy Audit, the Net project budget card shows the retrofit cost after incentives. Under its Manage menu, the analyzer chooses the Incentive Method: Measure-based or Whole building. Only methods the utility offers can be chosen. The Dashboard and the report use the same method.
Whole-building incentives add the Performance row (per kWh and kW saved) and the Building Area row (per ft²) when their switches are on. When the program sets a Max Limit (%), the building-area part is limited to that share of the project budget.
Payback and SIR
| Value | Formula | Where |
|---|---|---|
| Payback period | Cost of measures ÷ annual cost savings | Payback period card, Summary tab |
| Net payback period | (Cost of measures − incentives) ÷ annual cost savings | Summary tab, when there are incentives |
| SIR | Annual cost savings × life expectancy ÷ (retrofit cost − incentive) | Recommendations tab |
Savings aren’t discounted. An SIR above 1 means the measure pays for itself over its life. A payback under 30 years shows a green flag on the card.
The Summary tab shows the savings of all selected measures implemented together. The Recommendations tab shows each measure on its own, so its rows don’t add up to the summary.