R-21 Insulation

R-21 Fiberglass Insulation — Wholesale Supply

High-density R-21 batts for 2×6 wall framing. Wholesale pricing, no minimum order, same-day quotes, and next-day delivery anywhere in the U.S.

Call (929) 466-1426 Get a Quote Online

No minimum · Next-day delivery · Pay at delivery · All 50 states

Why R-21

The standard for 2×6 exterior walls.

Code-compliant in climate zones 4–8

Most energy codes in colder climates require R-20 or higher for above-grade walls. R-21 satisfies this requirement and is the go-to spec for compliant 2×6 construction.

High-density — stays in place

R-21 is a high-density batt. It's thinner than R-19 (5.5" vs 6.25") but denser, so it holds its shape in tall wall cavities and doesn't sag between inspections and drywall.

Better performance than R-19

The 10% improvement in thermal resistance adds up over the life of the building. If you're already using 2×6 framing, upgrading from R-19 to R-21 costs very little per job.

Quick Estimate

How many bags do you need?

Enter your square footage for an instant R-21 bag estimate.

Open full calculator for all R-values →

How to Order

Order R-21 in three steps.

Call or text your list

Tell us: R-21, batt width (15" or 23"), quantity, zip code, and delivery date. We respond within the hour — same business day.

Receive a firm invoice

We confirm stock and send an itemized invoice with your exact delivery window. No vague lead times, no surprise markups.

Delivered — then you pay

Delivery next business day on stocked product. Verify the order on arrival, then pay at delivery. No upfront payment.

R-21 FAQ

Common questions about R-21.

What's the difference between R-19 and R-21?

Both fit in a 2×6 cavity. R-21 is high-density — thinner but denser, with ~10% better thermal performance. Most climate zone 4+ codes now require at least R-20, making R-21 the standard choice. Full comparison →

Do you carry 15" and 23" width?

Yes. 15" is for 16" on-center framing; 23" is for 24" on-center. Specify when you call or submit a quote so we pull the right product.

Is there a minimum order?

No minimum. You can order 5 bags or 500 bags. Volume typically earns better per-bag pricing — ask about it when you call.

How fast can you deliver?

Next business day on stocked product when you order before 3pm EST. We deliver to all 50 states. Rush orders can sometimes be arranged — call to discuss.

Ready to order R-21?

Call or text with your quantity, width, and zip code. Same-day quote, next-day delivery on stocked product. Pay at delivery — no upfront payment required.