# Led replacement savings calculator

- Human page: https://happytails.ai/en/calculators/led-replacement-savings-calculator/
- Markdown: https://happytails.ai/en/calculators/led-replacement-savings-calculator.md
- Structured JSON: https://happytails.ai/agents/en/calculators/led-replacement-savings-calculator/index.json
- Visibility: public

## Tool capabilities

| Property | Value |
| --- | --- |
| Tool ID | `led-replacement-savings-calculator` |
| Category | calculators |
| Implementation | Registered implementation. Registration alone is not a production-quality guarantee. |
| Browser execution | Use the visible action or interactive controls. |
| Browser processing | Browser; see tool notes for network behavior. |
| HTTP API | Not callable through HTTP. |
| Browser-agent interface | run_current_tool |

### Implementation notes

Runs locally in your browser. Enter your own power, usage, efficiency and tariff assumptions; no live tariff lookup is performed. Results are estimates, not utility bills or engineering advice.

### Inputs and settings

No free-text input is required. Use the file inputs and/or settings below.

| Setting | Meaning | Control type | Default | Constraints |
| --- | --- | --- | --- | --- |
| `oldWatts` | Old bulb power (W) | number | 60 | min=0 step=any |
| `newWatts` | LED power (W) | number | 9 | min=0 step=any |
| `hoursPerDay` | Hours per day | number | 4 | min=0 max=24 step=any |
| `daysPerYear` | Days per year | number | 365 | min=0 max=366 step=any |
| `pricePerKwh` | Price per kWh | number | 0.3 | min=0 step=any |
| `quantity` | Quantity | number | 2 | min=1 step=1 |
| `purchaseCost` | Replacement cost | number | 20 | min=0 step=any |

### Browser-agent workflow

1. Open the human page in a browser that supports WebMCP.
2. Discover the interface exposed by that page; use its actual schema.
3. Select files on the page first when the tool requires files.
4. Call `run_current_tool` with valid input and settings.
5. Inspect the returned result or error and the displayed output. Retrieve files from the displayed download links.

Calls do not automatically copy or download results. Browser permissions still apply. Interface availability alone is not proof of successful execution.

### Planning specification

Runs locally with bounded numeric inputs and returns a complete JSON result. Tariffs, efficiency and usage are not looked up.

This describes intended requirements. Use the implementation notes, interface schema and observed output to determine current support.

### Complete machine-readable capability record

```json
{
  "id": "led-replacement-savings-calculator",
  "category": "calculators",
  "built": true,
  "requirements": "Runs locally with bounded numeric inputs and returns a complete JSON result. Tariffs, efficiency and usage are not looked up.",
  "implementation": {
    "fields": [
      {
        "key": "oldWatts",
        "label": "Old bulb power (W)",
        "value": 60,
        "type": "number",
        "min": 0,
        "step": "any"
      },
      {
        "key": "newWatts",
        "label": "LED power (W)",
        "value": 9,
        "type": "number",
        "min": 0,
        "step": "any"
      },
      {
        "key": "hoursPerDay",
        "label": "Hours per day",
        "value": 4,
        "type": "number",
        "min": 0,
        "step": "any",
        "max": 24
      },
      {
        "key": "daysPerYear",
        "label": "Days per year",
        "value": 365,
        "type": "number",
        "min": 0,
        "step": "any",
        "max": 366
      },
      {
        "key": "pricePerKwh",
        "label": "Price per kWh",
        "value": 0.3,
        "type": "number",
        "min": 0,
        "step": "any"
      },
      {
        "key": "quantity",
        "label": "Quantity",
        "value": 2,
        "type": "number",
        "min": 1,
        "step": 1
      },
      {
        "key": "purchaseCost",
        "label": "Replacement cost",
        "value": 20,
        "type": "number",
        "min": 0,
        "step": "any"
      }
    ],
    "input": false,
    "presentation": "metrics",
    "note": "Runs locally in your browser. Enter your own power, usage, efficiency and tariff assumptions; no live tariff lookup is performed. Results are estimates, not utility bills or engineering advice.",
    "example": {
      "input": "",
      "options": {
        "oldWatts": 60,
        "newWatts": 9,
        "hoursPerDay": 4,
        "daysPerYear": 365,
        "pricePerKwh": 0.3,
        "quantity": 2,
        "purchaseCost": 20
      }
    },
    "experience": {
      "automatic": false,
      "single": false,
      "inputMaxLength": 1000000,
      "inputMode": "text",
      "label": "Energy assumptions JSON",
      "placeholder": "{\n  \"oldWatts\": 60,\n  \"newWatts\": 9,\n  \"hoursPerDay\": 4,\n  \"daysPerYear\": 365,\n  \"pricePerKwh\": 0.3,\n  \"quantity\": 2,\n  \"purchaseCost\": 20\n}",
      "help": "Use the documented numeric fields. Up to 1,000,000 characters. Review the settings before running.",
      "action": null
    },
    "mode": "explicit",
    "interactive": false
  },
  "execution": "Browser interface",
  "api": null,
  "browser_agent": {
    "supported": true,
    "name": "run_current_tool",
    "discovery": "WebMCP on the human page in a supporting browser",
    "verification": "See audit/API-AUDIT.md; availability is not verification"
  }
}
```

## Page guide

Calculate a transparent home-energy estimate locally from the assumptions you enter.

How can we improve this tool?

Report a problem or share an idea.

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### How to use Led replacement savings calculator

1. Enter the energy assumptions and units.
2. Review the calculation and assumptions.
3. Download or copy the complete result.

## Useful next steps

- [Appliance electricity cost calculator](https://happytails.ai/en/calculators/appliance-electricity-cost-calculator/) ([Markdown](https://happytails.ai/en/calculators/appliance-electricity-cost-calculator.md))

- [Battery cycle cost calculator](https://happytails.ai/en/calculators/battery-cycle-cost-calculator/) ([Markdown](https://happytails.ai/en/calculators/battery-cycle-cost-calculator.md))

- [Ev charging cost calculator](https://happytails.ai/en/calculators/ev-charging-cost-calculator/) ([Markdown](https://happytails.ai/en/calculators/ev-charging-cost-calculator.md))

## Transparent energy estimate

Every result shows the assumptions it used. Check local tariffs, equipment specifications and utility statements before making a decision.