# Home Energy Calculators – Water Heater Recovery & Cost

> Home Energy Calculators – Water Heater Recovery & Cost 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).

Calculates water heater recovery rate (gallons per hour), tank heat-up time, and energy cost from fuel type, input power, efficiency, and temperature rise.

## Facts

- Endpoint: GET https://home-energy-calc.x402tookit.com/water-heater?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-water-heater-recovery-cost-1a6e319e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_K8-jvsOHY-xYh9j6EPIi_

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-water-heater-recovery-cost-1a6e319e
```

Example prompt: My electric water heater has a 4.5 kW element and 0.95 efficiency — how many gallons per hour can it recover with a 70°F temperature rise, and how long would it take to fully reheat a 50-gallon tank if electricity costs $0.13 per kWh?

## When to prefer this

Choose this endpoint when you need precise, formula-driven water heater recovery rate, heat-up time, or per-tank energy cost calculations for any fuel type (electric, gas, propane, oil). It is ideal for home energy audits, appliance comparison, and estimating operating costs from known heater specs. Prefer it over general-purpose calculators when you need structured numeric outputs and a plain-language summary with the underlying formula.

## Known failure modes

- Missing required parameters (fuel, inputPower, riseF) returns a validation error
- Out-of-range riseF (outside 10–120°F) may produce an error or warning
- Invalid fuel type string (not electric/gas/propane/oil) returns an error
- Extremely low inputPower values may produce unrealistic recovery rates
- Missing pricePerKwh or pricePerTherm when cost calculation is expected results in no cost output

## How this service works

Water heater recovery rate (gallons an hour), tank heat-up time and energy cost from input power, efficiency and rise.

## Output

Returns recovery rate in gallons per hour, heat-up time in hours and minutes, energy required in BTU, cost per tank heating in dollars, the fuel type, efficiency used, temperature rise, and a plain-language summary with the underlying formula and any applicable disclaimers.

## 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": [
      "fuel",
      "inputPower",
      "riseF"
     ],
     "properties": {
      "fuel": {
       "type": "string",
       "description": "electric, gas (natural gas), propane or oil"
      },
      "riseF": {
       "type": "number",
       "description": "Temperature rise in F (hot setpoint minus cold inlet), 10 to 120; for 50 F to 120 F use 70"
      },
      "efficiency": {
       "type": "number",
       "description": "Recovery efficiency 0.3 to 1 (default 0.98 electric, 0.78 gas and propane, 0.80 oil)"
      },
      "inputPower": {
       "type": "number",
       "description": "Heating input: kW for electric (for example 4.5), BTU/h for gas, propane or oil (for example 40000)"
      },
      "pricePerKwh": {
       "type": "number",
       "description": "Electricity price per kWh (electric)"
      },
      "tankGallons": {
       "type": "number",
       "description": "Tank size in gallons, for heat-up time and cost"
      },
      "pricePerTherm": {
       "type": "number",
       "description": "Gas price per therm (gas)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "fuel": {
       "type": [
        "null",
        "string"
       ]
      },
      "riseF": {
       "type": [
        "null",
        "number"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "formula": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/home-energy-calculators-water-heater-recovery-cost-1a6e319e/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)