What Is R-Value (And Why Building Owners Should Care)?

If you’re planning a metal building or thinking about upgrading one, you’ve probably heard the term R-value. It’s on insulation labels, in building codes, and in every conversation about energy efficiency.

But what is R-value, really? And why should building owners care?

Let’s break it down in a simple, helpful way—and show why it matters even more when it comes to Butler Building systems.

What Is R-Value?

R-value measures how well a material resists heat flow.

The higher the R-value, the better a material keeps heat from passing through it. It’s like a jacket for your building—the thicker and better the insulation, the warmer (or cooler) your interior stays.

R-value is expressed in units of:

ft² · hr · °F / BTU

This tells us how much heat a material blocks over time, across an area, at a given temperature difference.

Why Does It Matter?

• Lower energy bills: A high R-value reduces heating and cooling costs
• Improved comfort: Stops drafts, hot spots, and cold zones
• Code compliance: Many commercial buildings are required to meet minimum R-values
• Better ROI: Energy-efficient buildings have lower lifetime costs

How R-Value Works in Real Buildings

R-value doesn’t just depend on the material—it depends on the whole assembly: how the insulation is installed, what materials surround it, and whether there are thermal breaks or gaps.

For example:

• A wall with R-19 batt insulation might not truly deliver R-19 if there are air leaks or poor sealing
• Two walls with the same insulation but different wall framing can have different overall R-values

That’s why tested systems like those from Butler Manufacturing are so valuable—they're designed and verified as a complete assembly.

R-Value vs. U-Value (Quick Note)

While R-value measures resistance to heat, U-value measures how easily heat flows through a material. They are exact opposites:

U = 1 / R

So a wall with an R-value of 20 has a U-value of 0.05. Lower U-values = better insulation.

Common R-Values for Building Materials

Keep in mind: moisture, compression, and poor installation can reduce real-world performance.

How Butler Delivers Proven R-Value Performance

Butler doesn’t just supply insulation materials—they offer tested and engineered insulation systems that integrate with their roofs and walls.

✅ ThermaLiner™ Insulation System

• Used with MR-24, VSR, and Butlerib II roofs
• Offers R-values from R-22 up to R-41
• Includes interior metal liner for vapor and condensation control
• Easy to clean and improves building appearance

✅ TBS™ Insulation System

• Tested using a guarded hot box for verified performance
• Achieves tested R-values up to R-38.7
• Delivers consistent energy savings year-round

Unlike traditional batt insulation alone, Butler systems are engineered to perform as a full thermal barrier, tested as a whole.

How to Choose the Right R-Value

R-value needs depend on:

• Climate zone (cold climates need higher R-values)
• Building type (warehouses vs. offices vs. retail)
• Usage patterns (24/7 use vs. part-time occupancy)

In general, commercial buildings in the U.S. should aim for:

• Roofs: R-30 to R-40
• Walls: R-13 to R-21
• Floors over unheated spaces: R-13 to R-19

Check your local building codes or consult a Butler Builder® for region-specific guidance.

Final Takeaway: Don’t Just Look at the Number

Anyone can slap an R-value label on a roll of insulation. But that number doesn’t mean much unless the system is designed and installed properly.

That’s where Butler insulation systems stand apart:

• Tested and verified performance (not just estimated)
• Integrated with the roof and wall system
• Engineered for real-world energy savings

If you're building new or upgrading an existing Butler building, reach out to Butler MFG Parts. We supply factory-approved insulation components and can help you choose the system that fits your goals.

Need help improving your building’s energy performance? Contact Butler MFG Parts today and ask about our insulation upgrade options.