U-Value Calculator
Calculate the overall U-value of a building assembly from a list of individual R-values.
How to Use the U-Value Calculator
- List all layers of your wall, roof, or floor assembly.
- Look up the R-value for each layer (insulation, sheathing, air films, etc.).
- Enter all R-values as comma-separated values.
- Click Calculate for total R, U-value, and energy class.
حالات الاستخدام
- •Wall assembly thermal performance.
- •Roof U-value for energy compliance.
- •Comparing envelope upgrade options.
- •Passive house design verification.
الصيغة
R_total = R1 + R2 + ... + Rn. U = 1 / R_total. Energy class: A+ if U<0.2, A if U<0.5, B if U<1.0, C otherwise.
الأسئلة الشائعة
What is U-value?
U-value (thermal transmittance) is the rate of heat transfer through a building element. Lower U = better insulation.
How do I enter multiple R-values?
Enter all R-values separated by commas, e.g.: 3.5, 13, 0.68, 0.45
What is a good U-value for walls?
Passive house walls: U < 0.15. Modern construction: 0.2–0.4. Older buildings: >0.5.