How to Evaluate the Best IMP Panels: A Practical Cost-Benefit Playbook for Owners

Written By William Goodin

Insulated metal panels (IMPs) can be one of the highest impact decisions in a cold storage, food processing, controlled environment, or high performance envelope project. They influence energy use, construction schedule, insurance requirements, long-term durability, and even how smoothly your building gets permitted and commissioned.

IMP pricing also varies wildly. Depending on manufacturer, panel thickness, facings, coatings, joint profile, and performance requirements, IMP material pricing can range from about $3/SF to $15/SF. That spread is exactly why a structured cost-benefit analysis matters.

Below is the framework we use to help owners compare “apples to apples” and select the right panel system for their project.

Step 1: Define what “best” means for your building

Before you compare quotes, lock in the performance criteria that actually drive value:

  • Fire and insurance requirements (often the biggest divider)

  • Thermal performance (R-value, thermal bridging at joints)

  • Air and vapor control (joint design, gasket strategy, sealants)

  • Washdown and hygiene needs (food grade finishes, corrosion resistance)

  • Structural needs (spans, fastening approach, wind loads)

  • Schedule risk (lead times, shipping, installation support)

If you do not define these early, the lowest number on bid day can become the most expensive decision by punch list.

Step 2: FM rating vs. no FM rating, why it changes everything

Panels with no FM rating can be perfectly functional for certain low-risk occupancies, but they often introduce risk in three places:

  1. Insurance acceptance and premiums

  2. Design limitations (where and how the panels can be used)

  3. Future tenant flexibility (a building that is harder to insure is harder to lease)

FM Approved assemblies, by contrast, are tested and listed for property loss prevention performance. FM Approvals maintains the Approval Guide, which is effectively the source of truth for what is actually listed and how it must be installed.

Two FM standards show up constantly in IMP conversations:

  • FM 4880: commonly associated with Class 1 fire performance for insulated panels and interior finish materials.

  • FM 4881: exterior wall system criteria that builds on FM 4880 and adds additional requirements for exterior applications.

FM Global’s guidance also emphasizes a core goal with insulated panel construction: reduce the chance that panels add meaningful fuel to the occupancy fuel load, so sprinklers and protection features can do their job.

Practical takeaway: If your project is FM insured (or might be sold to an owner that is), start your panel selection with FM listed assemblies and design around them instead of trying to “value engineer into compliance” later.

Step 3: Polyisocyanurate (polyiso) cores vs. polystyrene (EPS), what owners should know

Most IMP discussions eventually come down to core selection. Two of the most common cores you will see are polyisocyanurate (polyiso) and expanded polystyrene (EPS).

Polyiso cores

Owners typically choose polyiso when they want:

  • Higher thermal performance per inch

  • A well-documented approach to long-term thermal resistance (LTTR), which is commonly referenced for foam products with captive blowing agents

Polyiso R-values vary by product and conditions, but many industry references place it higher per inch than EPS in typical applications.

EPS cores

Owners typically choose EPS when they want:

  • Cost efficiency

  • Consistent thermal performance over time (EPS relies on stabilized air in its cell structure rather than captive blowing agents)

  • Broad availability across many panel manufacturers

EPS R-value per inch varies by density, but it is often referenced around the R-4 range per inch.

Practical takeaway: Polyiso tends to win on “R per inch,” EPS often wins on “R per dollar.” The best choice depends on your energy model, thickness limits, and the real schedule and risk profile of the job.

Step 4: Build a real cost-benefit analysis, not a bid tab

When IMP quotes come back, it is tempting to compare $/SF and call it a day. A better approach is to score each option across five cost buckets.

1) Material cost (the obvious one)

Use your pricing range as the starting point, but normalize the quotes:

  • Same thickness

  • Same facings and coatings

  • Same joint type and accessories

  • Same trim package assumptions

If one quote is “cheap” because it excludes trims, sealants, clips, fasteners, closures, or shop drawings, it is not actually cheap.

2) Installed cost and labor productivity

Two panels priced the same can install very differently based on:

  • Panel width and weight

  • Joint complexity and gasket strategy

  • Tolerance sensitivity

  • Manufacturer installation support and field QA

If a panel system saves a week of schedule on a controlled environment project, that often beats a small material delta.

3) Energy and operating cost

IMPs are a long-term energy lever. Compare:

  • Effective R-value of the assembly

  • Joint thermal performance

  • Air leakage expectations and detailing plan

If your project has high delta-T conditions (freezers, processing rooms), small envelope improvements compound quickly.

4) Risk cost (insurance, fire performance, future resale)

If an FM listed assembly reduces insurer friction or future-proofing issues, that has real value. The FM Approval Guide is where you validate listings and required installation conditions.

5) Schedule cost (lead time, shipping, and certainty)

This is where owners get surprised.

Step 5: China-sourced FM-rated options vs. US-made options, the real trade

There are many high-quality panel options available globally, including FM-rated assemblies produced overseas, and owners sometimes see attractive pricing from China-sourced supply.

The trade is usually not quality versus quality, it is certainty versus uncertainty:

US-based manufacturing (often higher material cost)

Pros:

  • Potentially shorter lead times and easier logistics

  • Faster response on jobsite issues

  • Typically smoother coordination with detailing, trims, and replacements

Risks:

  • Capacity constraints during peak cycles

  • Pricing volatility depending on steel markets and workload

China-sourced panels (often lower material cost)

Pros:

  • Can be very competitive on $/SF ($3/SF-$8/SF, on average)

  • Many global suppliers market products tested to FM standards

Risks to manage:

  • Potentially longer lead times

  • Freight variability

  • Higher impact if something arrives wrong

    • Typically be mitigated through ordering additional quantities of panels, trim and accessories

Practical takeaway: If schedule is tight or the building must open on a fixed date, paying more for domestic lead time certainty can be the best value on the entire project.

Step 6: A quick due diligence checklist before you choose

Use this checklist to avoid the most common owner pitfalls:

  • Confirm whether the project requires FM 4880 and/or FM 4881 and validate the exact assembly listing

  • Confirm core type and thickness, and request thermal data appropriate to your use case (LTTR where applicable)

  • Confirm finishes and corrosion resistance for washdown environments

  • Validate accessory scope (trim, flashing, sealants, fasteners, closures)

  • Ask for realistic lead times tied to a production slot, not a marketing estimate

  • Understand install tolerances and the manufacturer’s field support model

  • Require clear warranty language, including joint performance expectations

IMP manufacturers and panel resources to shortlist

Here are the manufacturers and resources you asked to include:

Bottom line: choose the panel that protects your pro forma, not just your budget

The “best” IMP panel is the one that meets the right fire and insurance thresholds, delivers the required thermal and air performance, and arrives on time with a detailing package your installer can execute cleanly.

William Goodin
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