Siding R-Value Calculator

Mistake: Focusing only on siding R-value

Solution: Siding is just one layer. Often, adding foam board sheathing provides better improvement than insulated siding at lower cost.

Mistake: Ignoring thermal bridging

Solution: Wall studs conduct heat right through your insulation. Continuous exterior insulation eliminates this problem.

Mistake: Assuming old insulation is adequate

Solution: If your home was built before 1980, wall insulation is likely inadequate by today's standards—if it exists at all.

Mistake: Adding insulation without air sealing

Solution: Insulation works by trapping air. If air moves through it, R-value drops dramatically. Seal gaps first.

How much R-value do I need in my walls?

Code requirements vary by climate zone: R-13 to R-21 for most of the US. However, 'more is better' applies here—R-25 to R-30 walls are increasingly common in new construction.

Is insulated vinyl siding worth the extra cost?

In cold climates (zones 5-7), the energy savings typically pay back the premium in 7-12 years. In mild climates, the payback is longer, but you still get comfort and noise reduction benefits.

Can I add insulation when re-siding?

Absolutely—it's the best time. You can add rigid foam board over the existing sheathing before installing new siding. This is one of the most cost-effective energy improvements you can make.

What's the difference between R-value and U-factor?

R-value measures resistance to heat flow (higher is better). U-factor measures heat transfer rate (lower is better). They're inverses: U-factor = 1/R-value. Siding typically uses R-value; windows use U-factor.