# Heat pump versus boiler calculator

- Human page: https://happytails.ai/en/calculators/heat-pump-versus-boiler-calculator/
- Markdown: https://happytails.ai/en/calculators/heat-pump-versus-boiler-calculator.md
- Structured JSON: https://happytails.ai/agents/en/calculators/heat-pump-versus-boiler-calculator/index.json
- Visibility: public

## Tool capabilities

| Property | Value |
| --- | --- |
| Tool ID | `heat-pump-versus-boiler-calculator` |
| Category | calculators |
| Implementation | Registered implementation. Registration alone is not a production-quality guarantee. |
| Browser execution | Automatic updates after valid input or file selection. |
| Browser processing | Browser; see tool notes for network behavior. |
| HTTP API | Not callable through HTTP. |
| Browser-agent interface | run_current_tool |

### Implementation notes

Calculated on your device for annual heat demand up to 1 billion kWh. Enter fuel price and energy per unit from your bill or supplier; no regional fuel default is inferred.

### Inputs and settings

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

| Setting | Meaning | Control type | Default | Constraints |
| --- | --- | --- | --- | --- |
| `heat` | Annual useful heat demand (kWh) | number | 9000 | min=0 max=1000000000 step=any |
| `scop` | Heat pump seasonal COP | number | 3 | min=0 max=20 step=any |
| `electricityTariff` | Electricity price per kWh | number | 0.3 | min=0 max=100000 step=any |
| `fuel` | Boiler fuel | select | "Gas" | Allowed: Gas, Oil, LPG, Electricity, Other |
| `fuelUnit` | Fuel sales unit | text | "supplier unit" |  |
| `fuelKwhPerUnit` | Fuel energy per sales unit (kWh) | number | 10 | min=0 max=100000 step=any |
| `efficiency` | Boiler efficiency (%) | number | 90 | min=0 max=100 step=any |
| `fuelPrice` | Fuel price per sales unit | number | 1 | min=0 max=100000 step=any |
| `emissions` | Emissions comparison | select | "Exclude emissions" | Allowed: Exclude emissions, Use entered factors |
| `electricityCo2` | Electricity emissions (kg CO2e per input kWh) | number | "" | min=0 max=1000 step=any |
| `fuelCo2` | Fuel emissions (kg CO2e per input kWh) | number | "" | min=0 max=1000 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

Annual heat from 0 to 1 billion kWh, seasonal COP above 0 to 20, boiler efficiency above 0 to 100%, fuel energy above 0 to 100,000 kWh per sales unit, and prices from 0 to 100,000. Optional emissions factors from 0 to 1,000 kg CO2e per input kWh. Labels have at most 80 characters. Calculated on your device. Downloads: JSON report and results CSV.

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

### Complete machine-readable capability record

```json
{
  "id": "heat-pump-versus-boiler-calculator",
  "category": "calculators",
  "built": true,
  "requirements": "Annual heat from 0 to 1 billion kWh, seasonal COP above 0 to 20, boiler efficiency above 0 to 100%, fuel energy above 0 to 100,000 kWh per sales unit, and prices from 0 to 100,000. Optional emissions factors from 0 to 1,000 kg CO2e per input kWh. Labels have at most 80 characters. Calculated on your device. Downloads: JSON report and results CSV.",
  "implementation": {
    "fields": [
      {
        "key": "heat",
        "label": "Annual useful heat demand (kWh)",
        "value": 9000,
        "type": "number",
        "min": 0,
        "max": 1000000000,
        "step": "any"
      },
      {
        "key": "scop",
        "label": "Heat pump seasonal COP",
        "value": 3,
        "type": "number",
        "min": 0,
        "max": 20,
        "step": "any"
      },
      {
        "key": "electricityTariff",
        "label": "Electricity price per kWh",
        "value": 0.3,
        "type": "number",
        "min": 0,
        "max": 100000,
        "step": "any"
      },
      {
        "key": "fuel",
        "label": "Boiler fuel",
        "value": "Gas",
        "type": "select",
        "values": [
          "Gas",
          "Oil",
          "LPG",
          "Electricity",
          "Other"
        ]
      },
      {
        "key": "fuelUnit",
        "label": "Fuel sales unit",
        "value": "supplier unit",
        "type": "text",
        "maxLength": 80,
        "help": "For example litre, therm or kWh. This label does not choose an energy conversion."
      },
      {
        "key": "fuelKwhPerUnit",
        "label": "Fuel energy per sales unit (kWh)",
        "value": 10,
        "type": "number",
        "min": 0,
        "max": 100000,
        "step": "any",
        "help": "Editable example only. Use the same unit and heating-value basis as the supplied price and efficiency."
      },
      {
        "key": "efficiency",
        "label": "Boiler efficiency (%)",
        "value": 90,
        "type": "number",
        "min": 0,
        "max": 100,
        "step": "any"
      },
      {
        "key": "fuelPrice",
        "label": "Fuel price per sales unit",
        "value": 1,
        "type": "number",
        "min": 0,
        "max": 100000,
        "step": "any"
      },
      {
        "key": "emissions",
        "label": "Emissions comparison",
        "value": "Exclude emissions",
        "type": "select",
        "values": [
          "Exclude emissions",
          "Use entered factors"
        ]
      },
      {
        "key": "electricityCo2",
        "label": "Electricity emissions (kg CO2e per input kWh)",
        "value": "",
        "type": "number",
        "min": 0,
        "max": 1000,
        "step": "any",
        "showWhen": {
          "emissions": [
            "Use entered factors"
          ]
        }
      },
      {
        "key": "fuelCo2",
        "label": "Fuel emissions (kg CO2e per input kWh)",
        "value": "",
        "type": "number",
        "min": 0,
        "max": 1000,
        "step": "any",
        "showWhen": {
          "emissions": [
            "Use entered factors"
          ]
        }
      }
    ],
    "registrationFamily": "home-heating-costs",
    "input": false,
    "live": true,
    "presentation": "metrics",
    "note": "Calculated on your device for annual heat demand up to 1 billion kWh. Enter fuel price and energy per unit from your bill or supplier; no regional fuel default is inferred.",
    "experience": {
      "automatic": true,
      "single": true,
      "inputMaxLength": 1000000,
      "inputMode": "text",
      "label": "Heating assumptions",
      "placeholder": "Use the fields below",
      "help": "This calculator uses the fields below. Results update as you type. Up to 1,000,000 characters.",
      "action": null
    },
    "mode": "automatic",
    "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

Compare annual energy cost for the same useful heat demand, using heat-pump SCOP and an editable boiler fuel conversion, with optional emissions factors you supply.

### How to use Heat pump versus boiler calculator

1. Enter annual useful heat demand and the heat pump seasonal COP and electricity price.
2. Name the boiler fuel sales unit and enter its energy content, price and boiler efficiency.
3. Choose whether to include emissions and, if so, enter both sourced factors per input kWh.
4. Compare energy use, cost and any emissions difference, then download the JSON report or CSV.

How can we improve this tool?

Report a problem or share an idea.

Please leave out private information. Your message and the tool name go to our team via PostHog.

## 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))

- [Hot water energy calculator](https://happytails.ai/en/calculators/hot-water-energy-calculator/) ([Markdown](https://happytails.ai/en/calculators/hot-water-energy-calculator.md))

- [Insulation calculator](https://happytails.ai/en/calculators/insulation-calculator/) ([Markdown](https://happytails.ai/en/calculators/insulation-calculator.md))

## Compare equal heat

Both systems deliver the same useful heat. The heat pump electricity is heat divided by SCOP; boiler fuel energy is heat divided by efficiency. For 9,000 kWh of heat, SCOP 3 needs 3,000 electricity kWh, while 90% efficiency needs 10,000 fuel kWh.

### Fuel units are explicit

Gas, oil and LPG can be sold in different units. Enter the kWh in one sales unit using the same heating-value basis as the efficiency. The example value of 10 is editable and is not a region or fuel lookup. A label such as litre does not choose a conversion.

### Interpreting differences

A positive saving means lower heat-pump energy cost; a negative saving means higher cost. Costs exclude standing charges, installation, finance, servicing and backup heat. Optional emissions use your entered factors, without bundled emission assumptions.