United States version
How it works
Evaluate an audit recommendation using a specified reduction in energy spending. The Irish optional baseline uses Electric Ireland EnergySaver 14 DD/online-bill tariff variants with separately dated PSO periods, not a national average or a future-price guarantee.
This is the United States planning view, with monetary inputs and outputs in USD. A currency label does not establish that a tax rate, construction price, coverage rule or legal limit has been verified locally. The inputs and limitations below describe the actual scope.
Input query strings and outputs
Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.
Input query strings
7-
?annualEnergyCost=Manual baseline: annual energy spendingMoney · Required · Default: 2,400
-
?savingPercent=Audit-supported variable-spending reduction assumptionPercentage · Required · Default: 20
-
?projectCost=Project priceMoney · Required · Default: 5,000
-
?incentive=Confirmed eligible incentiveMoney · Required · Default: 0
-
?extraMaintenance=Additional annual maintenanceMoney · Required · Default: 0
-
?years=Analysis yearsNumber · Required · Default: 15
-
?discountRate=Discount ratePercentage · Required · Default: 4
Outputs
6-
baselineCostEntered or modeled baseline annual spendingCurrency · Currency: USD
-
fixedCostTariff standing charge and PSO, not reduced by energy efficiencyCurrency · Currency: USD
-
capitalNet capital costCurrency · Currency: USD
-
annualSavingFirst-year net savingCurrency · Currency: USD
-
paybackSimple payback, yearsNumber · Primary output
-
npvDiscounted net valueCurrency · Currency: USD
Formula
Annual net saving = eligible variable energy spending × reduction fraction − additional maintenance. Fixed standing charges and PSO are not reduced by a consumption-saving percentage.
Calculations retain numeric precision internally. Displayed values are rounded for readability. Quantities that must be purchased as whole units are rounded up only where the formula explicitly requires it.
Read the inputs before calculating
- Manual baseline: annual energy spending: Enter the quantity described by the label.
- Audit-supported variable-spending reduction assumption: Enter the quantity described by the label.
- Project price: Enter the quantity described by the label.
- Confirmed eligible incentive: Enter the quantity described by the label.
- Additional annual maintenance: Enter the quantity described by the label.
- Analysis years: Enter the quantity described by the label.
- Discount rate: Enter the quantity described by the label.
Reproducible worked example
The following is a fictional arithmetic example, not a local quote, a verified claimant or a market forecast. Its values are included so the formula can be checked. The form does not automatically confirm any verification checkbox.
| Input | Example value |
|---|---|
| Manual baseline: annual energy spending | 2,400 |
| Audit-supported variable-spending reduction assumption | 20 |
| Project price | 5,000 |
| Confirmed eligible incentive | 0 |
| Additional annual maintenance | 0 |
| Analysis years | 15 |
| Discount rate | 4 |
| Output | Calculated result |
|---|---|
| Entered or modeled baseline annual spending | USD 2,400 |
| Tariff standing charge and PSO, not reduced by energy efficiency | USD 0 |
| Net capital cost | USD 5,000 |
| First-year net saving | USD 480 |
| Simple payback, years | 10.4167 |
| Discounted net value | USD 336.826 |
Interpreting a changed assumption
Start with one complete scenario and change only one input when diagnosing a difference. Recheck units, the period of every rate, whether an amount is recurring or one-off, and whether a cost is already included elsewhere. A larger calculated benefit is not evidence that an assumption is more likely to occur.
Limitations
- This is an audit scenario, not a diagnosis of the building. Add interacting upgrades only after accounting for overlapping savings.
Frequently asked questions
What does this Home Energy Audit Savings result represent?
Evaluate an audit recommendation using a specified reduction in energy spending. The Irish optional baseline uses Electric Ireland EnergySaver 14 DD/online-bill tariff variants with separately dated PSO periods, not a national average or a future-price guarantee. It applies the displayed formula to your inputs; it does not infer omitted facts.
Are the starting amounts verified United States prices or legal rules?
No. Numeric defaults are illustrative unless an input or dated reference explicitly identifies a researched component. Currency is USD; local quotes, eligibility and unsupported rules must be entered and verified separately.
What must I check before relying on the result?
Check the input units, supplier or authority evidence, the stated model exclusions and the period used for costs. This arithmetic does not supply missing site-specific design or local legal rules.
Can I compare or share different assumptions?
Change one assumption at a time and use the browser-local project or share controls. A shared URL contains the encoded input values; do not include information you do not wish to disclose.
Sources and reference scope
- DOE energy-use arithmetic — retrieved 2026-09-24. Energy consumption versus power; not a local tariff or an approval of this implementation.
- PVWatts: site-specific solar estimation — retrieved 2026-09-24. External site-yield model. AskCalculators uses your entered yield; it does not call or reproduce PVWatts.
- DOE insulation overview — retrieved 2026-09-24. Insulation and thermal resistance concepts; not structural or code approval.
These references support only their stated scope. They are not evidence that every local rule or price needed by the master expansion has been loaded.