Studio Matrx Monthly · Volume 1 · Issue 1 · June 2026
Amogh N P
 In loving memory of Amogh N P — Architect · Designer · Visionary 
Door U-Value Calculator

Door U-Value Calculator

Choose the door type, core or glazing, frame material and whether it has a thermal break — and get an estimated U-value (W/m²K), a rating versus Eco-Niwas Samhita guidance, and what would improve it. Indicative only — confirm with a manufacturer EPD or lab-tested value.

Your door

PU/XPS-filled leaf; strong insulator for external doors. Multi-chamber; very low conductivity. U-value lower is better. Bands are aligned to Eco-Niwas Samhita (ENS 2018) / ECBC intent for external openings — indicative India 2026; varies by product, glass spec and detailing.

Estimated U-value (W/m²K) · lower is better

0.00W/m²K

Excellent vs ENS guidance

Strong insulation — suits high-performance / green-rated external doors.

Leaf / glazing U

1.40

W/m²K (before frame)

Assembly U

1.05

W/m²K (incl. frame)

Rating

Excellent

vs ENS bands

Excellent
Good
Fair
Poor

Indicative ENS-aligned bands for an external door: ≤1.8 excellent · ≤2.6 good · ≤3.6 fair · >3.6 poor.

What would improve it

  • Already well-specified — verify with the manufacturer's lab-tested U-value and EPD.

How your door type compares

Reference: a typical external door of each core with a uPVC frame, no glazing and a thermal break. Lower bars are better. Your selected type is highlighted.

Spec a thermally smart door

DesignAI matches door core, glazing, frame and thermal detailing to your climate and cooling load — and helps you read a manufacturer's U-value and EPD.

How this works & assumptions. The U-value (thermal transmittance, W/m²K) measures how readily heat passes through the door — lower means better insulation and less AC heat gain. We start from an indicative leaf/core U-value, blend in the glazed fraction for glazed doors, nudge for the frame material, and credit a thermal break (which helps most on conductive metal frames). Rating bands are aligned to the intent of Eco-Niwas Samhita (ENS 2018) and ECBC 2017 for external openings.

These are indicative estimates only — confirm the real figure with the manufacturer's lab-tested U-value (ISO 10077 / hot-box) and EPD. This tool is not a substitute for an energy or green-building consultant. Where you compare product costs, note 18% GST applies. Glass type (low-e, gas fill), seal quality and on-site detailing can move the result materially.