Insulation Calculator
Estimate the target R-value, required thickness, material volume, and cost range for insulating an attic, wall, floor, or basement — using DOE climate-zone recommendations you can also override.
Input
DOE climate zone — sets the recommended R-value target (ENERGY STAR guide midpoints).
Leave blank to use the recommended R-value for the zone and application above.
Output
| Metric | Value |
|---|---|
| No data yet | |
One-line overview of the target R-value, thickness, and cost range.
More ways to use this tool
REST API
curl -X POST https://api.iotools.cloud/v1/tool/insulation-calculator \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"zone": "5",
"application": "attic",
"area": "1200",
"material": "fiberglass-batt",
"targetROverride": ""
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `insulation-calculator` tool (Insulation Calculator) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.
Embed widget
<iframe
src="https://iotools.cloud/embed/insulation-calculator/"
width="100%" height="520" frameborder="0" scrolling="no" loading="lazy"
title="Insulation Calculator — iotools.cloud"
sandbox="allow-scripts allow-forms allow-same-origin allow-downloads allow-popups allow-popups-to-escape-sandbox"
allow="clipboard-write"
style="width:100%;border:1px solid #e5e7eb;border-radius:12px;overflow:hidden"></iframe>
<script src="https://iotools.cloud/embed.js" async></script>Drop this into your own page — free, no key required, just a link back.
| Cost per API/MCP call | From 5 credits |
|---|---|
| Need more credits? | View pricing |
Also available with
Guides
The Insulation Calculator estimates how much insulation a home project needs. Pick your climate zone and the assembly you're insulating (attic, wall, floor, or basement wall) and it looks up a recommended R-value target from the DOE/ENERGY STAR climate-zone guide, then works out the required thickness, the volume of material, and a cost range for the insulation type you choose.
How to use it
- Pick your climate zone (1 = very hot, 8 = subarctic) — this sets the recommended R-value.
- Choose where you're insulating: attic/ceiling, wall cavity, floor over unconditioned space, or a basement/crawl-space wall.
- Enter the area to insulate, in square feet.
- Pick an insulation material — fiberglass batt, mineral wool batt, blown-in cellulose, open- or closed-cell spray foam, or rigid foam board.
- Optionally enter a target R-value to override the zone's recommendation, e.g. to match a local building code.
Results update instantly: the target R-value, the thickness needed for your chosen material, the total volume of insulation, and a low-high cost range. A one-line summary is provided for quick copying.
Where do the recommended R-values come from?
They're the midpoints of the ENERGY STAR "Recommended Home Insulation R-Values" guide, keyed by DOE climate zone (1-8) and assembly. They're a starting point, not a code requirement — always check your local building code for the exact minimum.
How is thickness calculated?
Thickness = target R-value / material's R-value per inch. Fiberglass and mineral wool batts run around R-3.2 to R-3.7 per inch, blown cellulose around R-3.5, and closed-cell spray foam as high as R-6.5 per inch — which is why a high R-value target needs far less closed-cell foam than fiberglass to reach the same performance.
How accurate is the cost range?
It's a rough estimate from typical published material costs per square foot per R-value, multiplied by your area and target R-value. Actual pricing varies by region, installer labor, and whether you DIY — treat it as a ballpark for budgeting, not a quote.
Is my data private?
Completely. Every calculation runs entirely in your browser. Nothing you type is uploaded, stored, or sent to a server.
For material quantities on a specific room, try the Floor Tile Area Calculator or the Lumber Calculator for framing estimates.