# Home Energy Calculators – Insulation R-Value & U-Factor

> Home Energy Calculators – Insulation R-Value & U-Factor 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 the total R-value and U-factor of a wall or roof assembly from material layers and thickness, with optional framing-fraction correction and heat flow computation.

## Facts

- Endpoint: GET https://home-energy-calc.x402tookit.com/insulation-r-value?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-insulation-r-value-u-factor-18883b96
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_IjfIYnSCUa7I1EfCcNg3t

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-insulation-r-value-u-factor-18883b96
```

Example prompt: Calculate the R-value and U-factor of a wall assembly made up of 0.5-inch drywall, 3.5-inch fiberglass batt cavity, and 0.6-inch sheathing, with a 25% framing fraction and 3.5-inch framing depth — include the air films in the result.

## When to prefer this

Use this endpoint when you need to compute the thermal resistance (R-value) and conductance (U-factor) of a specific wall or roof assembly from its constituent material layers, especially when framing members are present and a parallel-path correction is needed. It is more appropriate than a generic heat-loss calculator when the goal is to evaluate or compare insulation assemblies layer by layer rather than estimate whole-building energy loads.

## Known failure modes

- Missing required 'layers' parameter returns a validation error
- Unrecognized material name in layers string may return null R for that layer
- framingFractionPercent outside the 5–40 range may produce unexpected results
- Very thin or zero thickness values may yield near-zero layer R-values
- Malformed layers string (wrong delimiter or format) may fail to parse any layers

## How this service works

R-value and U-factor of a wall or roof assembly from layers and thickness, with a framing-fraction correction and heat flow.

## Output

Returns the total assembly R-value, U-factor, a breakdown of R-value per layer (with source and thickness), the framing-corrected effective R-value and U-factor when a cavity and framing fraction are provided, and optionally the heat flow in BTU/h when area and temperature difference are supplied.

## 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": [
      "layers"
     ],
     "properties": {
      "cavity": {
       "type": "string",
       "description": "Insulated cavity layer as material:inches or name:Rr (for example 'fiberglass batt:3.5'); with framing it is combined in parallel"
      },
      "layers": {
       "type": "string",
       "description": "Lines material:inches or name:Rr separated by semicolons, for example 'drywall:0.5; cavity insulation:3.5r; sheathing:0.6r'. Materials: fiberglass batt, cellulose loose-fill, open-cell spray foam, closed-cell spray foam, eps board, xps board, polyiso board, softwood framing, drywall, plywood"
      },
      "deltaTF": {
       "type": "number",
       "description": "Temperature difference in F, with areaSqFt"
      },
      "areaSqFt": {
       "type": "number",
       "description": "Surface area in square feet, to get heat flow"
      },
      "includeAirFilms": {
       "type": "boolean",
       "description": "true to add the interior and exterior air-film resistances (R-0.68 and R-0.17), default false"
      },
      "framingDepthInches": {
       "type": "number",
       "description": "Depth of the framing member in inches (default 3.5 for a 2x4); used with cavity"
      },
      "framingFractionPercent": {
       "type": "number",
       "description": "Share of the wall area that is framing, 5 to 40 (default 25, typical for 16-inch spacing)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "layers": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "object",
        "properties": {
         "r": {
          "type": [
           "null",
           "number"
          ]
         },
         "layer": {
          "type": [
           "null",
           "string"
          ]
    
… (truncated)
```

## More

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