# Home Energy Calculators – Solar Sizing

> Home Energy Calculators – Solar Sizing is a paid API for AI agents from home-energy-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-30).

Sizes a rooftop solar system from annual kWh consumption and peak sun hours, returning system kW, panel count, annual output, savings, and simple payback period.

## Facts

- Endpoint: GET https://home-energy-calc.x402tookit.com/solar-sizing?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/home-energy-calculators-solar-sizing-d2bc10a0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Jd1O6n2AsOi_J0c7ZTpwD

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability home-energy-calculators-solar-sizing-d2bc10a0
```

Example prompt: My home uses about 14,400 kWh per year, I get 5.5 peak sun hours per day, electricity costs $0.14 per kWh, installed solar runs $3 per watt, and I qualify for a 30% federal tax credit — how big a system do I need and what's the simple payback?

## When to prefer this

Use this endpoint when you need a fast, parameterized solar sizing computation based on known annual consumption and local peak sun hours, especially when you also want financial outputs like payback period and annual savings. Prefer it over general-purpose LLM solar estimates when you want a deterministic, formula-based result with explicit loss factors (NREL PVWatts default) and incentive modeling.

## Known failure modes

- Missing required annualKwh or peakSunHours parameters returns a validation error
- Out-of-range values (e.g. peakSunHours > 8 or annualKwh < 100) rejected with error message
- offsetPercent outside 10–150 range causes a validation failure
- incentivePercent > 100 returns an error
- panelWatts outside 100–800 range rejected
- Network timeout or service unavailability returns a non-200 HTTP status

## How this service works

Size a rooftop solar system from annual kWh and peak sun hours: kW, panel count, yearly output, savings and simple payback.

## Output

Returns a JSON object with system size in kW DC, number of panels, panel wattage, annual energy output, coverage percentage, gross and net system cost, annual savings, and simple payback period in years, along with a summary and disclaimer.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "annualKwh",
      "peakSunHours"
     ],
     "properties": {
      "annualKwh": {
       "type": "number",
       "description": "Electricity to offset per year, kWh (100 to 1,000,000)"
      },
      "panelWatts": {
       "type": "number",
       "description": "Watts per panel, 100 to 800 (default 400)"
      },
      "costPerWatt": {
       "type": "number",
       "description": "Installed cost per watt before incentives, for payback"
      },
      "pricePerKwh": {
       "type": "number",
       "description": "Electricity price per kWh, for savings"
      },
      "peakSunHours": {
       "type": "number",
       "description": "Average peak sun hours per day at your site, 1 to 8 (most US sites 3.5 to 6)"
      },
      "offsetPercent": {
       "type": "number",
       "description": "Share of use to cover, 10 to 150 (default 100)"
      },
      "incentivePercent": {
       "type": "number",
       "description": "Tax credit or rebate as % of cost, 0 to 100 (default 0)"
      },
      "systemLossPercent": {
       "type": "number",
       "description": "All system losses, 0 to 50 (default 14, the NREL PVWatts default)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/home-energy-calculators-solar-sizing-d2bc10a0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from home-energy-calc.x402tookit.com](https://www.zero.xyz/host/home-energy-calc.x402tookit.com/llms.txt)