DIY

How Much Insulation Do You Need?

Built by Kevin Glover · @gloverbuilds · Verified formula

Calculate batts, rolls, or blown-in insulation by R-value, area, and framing type.

📅 Updated April 2026 ✅ Formula verified 📖 4 min read 🆓 Free · No sign-up

In this article

R-Value Requirements by Climate Zone
Insulation Types Compared

In Deutschland

GEG (Gebäudeenergiegesetz) schreibt U-Werte vor: Dach 0,24 W/(m²K), Wand 0,24, Kellerdecke 0,30. Mineralwolle 035: 14-16 cm für Dach, 12-14 cm für Wand. Kosten: 20-50 €/m² Material. KfW-Förderung und BAFA-Zuschüsse reduzieren die Kosten um 15-40% — immer beantragen!

Typen

Mineralwolle (Glas/Stein): 5-15 €/m² (Standard). EPS/XPS (Styropor): 8-20 €/m². Holzfaser: 15-35 €/m² (ökologisch). Zellulose (Einblas): 15-25 €/m². Die energetische Sanierung ist in Deutschland durch GEG und Förderprogramme ein Megathema.

⚡ CalcWolf Insight

The biggest energy savings come from insulating the attic first — heat rises, and an under-insulated attic loses 25-30% of a home's heating energy. Adding insulation from R-11 to R-38 in the attic typically pays for itself in 2-3 years through lower heating bills.

Frequently asked questions

Wie dick muss die Dämmung sein?▾

Dach: 14-20 cm. Fassade: 12-16 cm. Kellerdecke: 8-12 cm. Abhängig vom Material und Ziel-U-Wert.

Welche Förderung gibt es?▾

BAFA: 15-20% der Kosten. KfW-Kredit: günstige Zinsen. iSFP-Bonus: +5%. Immer VOR Baubeginn beantragen!

✓ Math logic verified against primary sources → See our verification process

Kevin Glover · @gloverbuilds

Founder, CalcWolf · GLVTS · Blickr

All formulas sourced from primary references — IRS publications, peer-reviewed research, and official standards. Results are tested against independent reference calculators before publishing. Rates and brackets updated when official sources change. Editorial policy →