# Insulation payback calculator - Human page: https://happytails.ai/en/calculators/insulation-payback-calculator/ - Markdown: https://happytails.ai/en/calculators/insulation-payback-calculator.md - Structured JSON: https://happytails.ai/agents/en/calculators/insulation-payback-calculator/index.json - Visibility: public ## Tool capabilities | Property | Value | | --- | --- | | Tool ID | `insulation-payback-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. Enter the element area, before/after U-values and local heating degree days. This is a steady-state heating estimate for one element. ### Inputs and settings No free-text input is required. Use the file inputs and/or settings below. | Setting | Meaning | Control type | Default | Constraints | | --- | --- | --- | --- | --- | | `areaUnit` | Area unit | select | "m²" | Allowed: m², ft² | | `area` | Element area | number | 100 | min=0 step=any | | `beforeU` | U-value before (W/m² K) | number | 1.5 | min=0 max=20 step=any | | `afterU` | U-value after (W/m² K) | number | 0.5 | min=0 max=20 step=any | | `degreeDays` | Heating degree days (K days) | number | 2000 | min=0 max=20000 step=any | | `performance` | Heating efficiency fraction or seasonal COP | number | 0.8 | min=0 max=20 step=any | | `tariff` | Fuel or electricity price per input kWh | number | 0.1 | min=0 max=100000 step=any | | `installedCost` | Installed cost | number | 3000 | min=0 max=1000000000000 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 Element area above 0 to 1,000,000 m², U-values 0 to 20 W/m² K, heating degree days 0 to 20,000 K days, heating efficiency or COP above 0 to 20, price per input kWh 0 to 100,000 and installed cost 0 to 1 trillion in one currency. Area accepts m² or ft². 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": "insulation-payback-calculator", "category": "calculators", "built": true, "requirements": "Element area above 0 to 1,000,000 m², U-values 0 to 20 W/m² K, heating degree days 0 to 20,000 K days, heating efficiency or COP above 0 to 20, price per input kWh 0 to 100,000 and installed cost 0 to 1 trillion in one currency. Area accepts m² or ft². Calculated on your device. Downloads: JSON report and results CSV.", "implementation": { "fields": [ { "key": "areaUnit", "label": "Area unit", "value": "m²", "type": "select", "values": [ "m²", "ft²" ] }, { "key": "area", "label": "Element area", "value": 100, "type": "number", "min": 0, "step": "any" }, { "key": "beforeU", "label": "U-value before (W/m² K)", "value": 1.5, "type": "number", "min": 0, "max": 20, "step": "any" }, { "key": "afterU", "label": "U-value after (W/m² K)", "value": 0.5, "type": "number", "min": 0, "max": 20, "step": "any" }, { "key": "degreeDays", "label": "Heating degree days (K days)", "value": 2000, "type": "number", "min": 0, "max": 20000, "step": "any", "help": "Enter local Celsius/Kelvin degree days at a suitable balance temperature. Fahrenheit degree days must be divided by 1.8 first." }, { "key": "performance", "label": "Heating efficiency fraction or seasonal COP", "value": 0.8, "type": "number", "min": 0, "max": 20, "step": "any", "help": "For example 0.8 for 80% efficiency, or 3 for a heat pump seasonal COP of 3." }, { "key": "tariff", "label": "Fuel or electricity price per input kWh", "value": 0.1, "type": "number", "min": 0, "max": 100000, "step": "any" }, { "key": "installedCost", "label": "Installed cost", "value": 3000, "type": "number", "min": 0, "max": 1000000000000, "step": "any" } ], "registrationFamily": "home-heating-costs", "input": false, "live": true, "presentation": "metrics", "note": "Calculated on your device. Enter the element area, before/after U-values and local heating degree days. This is a steady-state heating estimate for one element.", "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 Estimate annual heating energy and cost saved by changing an element’s U-value, using your local degree days, heating efficiency and installation cost. ### How to use Insulation payback calculator 1. Enter the insulated area and its whole-element U-values before and after the work. 2. Enter local heating degree days in K days, heating efficiency or COP, and the price per input kWh. 3. Enter installed cost and review annual energy and cost savings. 4. Check the model boundaries before using simple payback, 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)) ## Annual heat transfer The estimate uses U-value × area × heating degree days × 24 / 1000 to calculate useful heat in kWh. Use U-values for the whole element, including the construction layers you intend to compare. Enter local degree days at an appropriate balance temperature; Fahrenheit degree days must first be divided by 1.8. ### From heat to cost Useful heat is divided by heating efficiency or seasonal COP before applying the input-energy price. Enter 0.8 for 80% efficiency or 3 for a seasonal COP of 3. The example 100 m², U-values 1.5 and 0.5, and 2,000 K days saves 4,800 useful heat kWh. ### Simple payback limits Simple payback is installed cost divided by positive annual cost saving. Equal or worse U-values and zero tariffs can produce no payback or a negative saving. The model excludes cooling, thermal bridges, air leakage, solar gains, behavioural changes, grants, finance and tariff changes.