Insulation is a SCAM (& the truth about Havelock and Hushmat)

Product reviewed (as discussed in the video)

This video isn’t a single-product review; it’s a comparative take on bus/van insulation materials, with specific criticism aimed at:

• Havelock wool (bat-style insulation)
• Hushmat / “kill mat” (radiant barrier/insulation marketed with high R-values)

The creator also praises/uses several alternatives, especially:

• Closed-cell polyurethane spray foam
• Reflectix (radiant barrier for specific applications)
• XPS rigid foam for floors (and notes polyiso performs worse in cold temperatures)

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Main claims & features of key insulation options

1) Closed-cell polyurethane spray foam (creator’s preferred “best overall”)

Why it’s recommended

• Best for conduction control (the most important heat-transfer mode for bus walls/ceilings/floors).
• Fills gaps/nooks/crannies, reducing air gaps.
• Acts as a vapor barrier when properly installed, reducing moisture reaching cold metal surfaces.
• Adds structural rigidity to the wall/structure and reduces vibration/humming.
• Claimed to reduce the need for sound-deadening mat/kill mat because of rigidity.

Pros

• High insulating performance (especially conduction)
• Vapor/moisture management (reduced condensation risk)
• Better structural outcome (less vibration)
• Generally improves overall “build protection” vs lesser insulation choices

Cons (acknowledged)

• People avoid it due to chemical/off-gassing concerns
• The creator argues off-gassing concerns are outweighed by moisture/mold/rust risks of alternatives for his priorities.

User experience / installation

• Requires correct mixing, full cure, and adhesion to perform correctly.
• He prefers professionals for spray foam and claims sometimes it’s cost-competitive.

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2) Reflectix (radiant barrier; praised but only for the right use)

What he says it’s best for

• Radiant heat blocking when there’s a clear air/radiant separation (e.g., windows, firewall/engine-bay radiant situations).
• Example uses:
  • Lining windows in summer to block solar radiation
  • Using it/shiny barrier near engine bay/firewall to reflect infrared radiation

Important caveat

• Reflectix’s marketing claims can be confusing:
  • If used without radiant-barrier conditions (e.g., pressed against warm mass / no air gap), it behaves more like a thin conductive layer and provides far less benefit than “high R” marketing implies.

Pros

• Excellent for radiant blocking in targeted applications
• Easy cut-and-fit rolls

Cons

• Not a reliable whole-wall R-value replacement when installed in the wrong configuration (especially where it’s relied on for conduction).

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3) Havelock wool / bat-style wool insulation (criticized heavily)

Main objections

• Doesn’t hold shape well in a moving bus: over time, it can sag and fall, leaving gaps.
• Requires serious vapor management because it doesn’t inherently behave like the vapor-barrier performance of closed-cell spray foam.
• Emphasis on variable / intelligent / one-way vapor barriers to prevent warm moist interior air from condensing on cold steel.

Moisture/vapor argument

• Wool’s moisture claims are overstated (per the creator).

• In cold climates with daily moisture sources (breathing, cooking, showers, propane combustion byproducts), interior humidity can raise the dew point → condensation on cold bus skin → mold/rust risk unless vapor control is done carefully.

• He argues Havelock’s marketing implies a vapor barrier may not be necessary, but a page on their site acknowledges vapor barriers can be essential for many builds (including school buses).

Pros (acknowledged indirectly)

• Wool has moisture-related properties in general (he notes wool sweaters/socks manage moisture well in other contexts).

Cons

• High risk of inadequate performance in mobile/steel builds unless installed with:
  • secure mechanical placement, and
  • correct variable vapor barrier strategy, and
  • sufficient internal heating/drying behavior (his broader building-science framing)

Overall stance

• “Overblown” marketing; he considers it a risky choice for his use case.

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4) Hushmat / “kill mat” (targeted as marketing misinformation)

What’s claimed by Hushmat (per the video)

• An influencer claimed it can replace foam in subfloors and achieve R-value ~7 with about 1/8 inch thickness.

Creator’s rebuttal

• He contacted the company (CEO responded).
• He argues their R-value claims don’t make sense physically:
  • Radiant barriers can produce misleading high R-value in certain radiant scenarios.
  • But between metal floor pan and plywood subfloor, he claims it’s primarily conduction, not radiation.
  • Therefore, butyl/rubber + thin layers should yield far less than “R7.”
• He also claims he tested the logic of scaling:
  • If 1 layer gives “R7 per 1/8 inch,” two layers should nearly double performance.
  • But the CEO allegedly said you wouldn’t get linear gains—only a small incremental improvement (“teens of percent”).
  • Creator interprets this as evidence that the “R7” marketing isn’t based on true conductive insulation.

Cost comparison / practical verdict

• He says it’s expensive (citing ~$400 for 50 sq ft).
• He concludes the money is better spent on something else or even doing nothing if the goal is true insulation performance between subfloor and metal pan.

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Other technical guidance / comparisons mentioned (key points)

Heat transfer framework (used throughout comparisons)

He distinguishes three heat-transfer types:

• Radiation (best targeted by radiant barriers like Reflectix in specific setups)
• Convection (managed by air sealing / avoiding drafts)
• Conduction (most important for bus metal-shell builds; foam/conduction control matters most)

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Floor insulation: XPS vs polyiso

• Prefers XPS (extruded polystyrene) for floors because:
  • better compressive strength for a “floating subfloor” load
  • higher effective performance in cold conditions
• Notes polyiso: R-value drops significantly at lower temperatures, making it less suitable for floors where cold is most relevant.

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Subfloor system specifics (for the creator’s build approach)

• Uses XPS under a full-floating subfloor:
  • 3/4 inch tongue-and-groove OSB/Advantec-type subfloor
  • doesn’t frame subfloors (per his description)
• Claims XPS compressive strength (cites 25 psi, or at minimum 15 psi) is sufficient for loads.
• Mentions a test: dropping a portion of bus weight (rear axle half) without deformation.

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Thermal bridging (important installation consequence)

• Thermal bridging occurs through framing members (studs/ribs) that short-circuit insulation.
• Certain wall framing choices can destroy insulation effectiveness even with good insulation present.

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Vapor barrier and framing mistakes (major user-experience risk)

• If warm, moist air reaches cold metal ribs, he expects condensation and later symptoms like dripping ceiling / leaks.
• He criticizes installs that “sister” wood tightly against steel without proper insulation thickness/vapor control.

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His framing approach + moisture claim

• Wood strapping is in contact with steel ribs, but:
  • the whole rib is covered with enough spray foam thickness (he mentions ~1.5 inches),
  • so warm moist air allegedly never reaches the wood/steel connection.
• He argues sill plate gasket there won’t help much compared to foam thickness and vapor control.

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Windows (related moisture risk)

• Double-pane RV windows can still develop condensation.
• He claims their windows have drains that route moisture outside the bus.
• He strongly discourages using stock bus windows in a full-time 4-season live-in build because they may lack proper drainage, causing condensation/mold within walls.

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Air exchange / ventilation philosophy

• Recommends building an airtight rig, controlling air exchange via:
  • opening windows (basic),
  • powered roof vents,
  • heat exchangers / energy recovery ventilators for controlled fresh air without big drafts.
• The main goal is to minimize uncontrolled moist interior air entering wall cavities.

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Pros & cons summary (as implied by the video)

• Best overall for his use case:

  • Closed-cell spray foam (best conduction control + vapor/moisture management + rigidity)

• Good in specific radiant-only scenarios:

  • Reflectix (windows, radiant engine/firewall blocking), but not a general conduction substitute

• High risk unless installed with rigorous vapor control and secure placement:

  • Havelock wool (bat-style) in mobile steel environments

• Marketing skepticism / likely poor fit for his stated insulation target:

  • Hushmat (he argues the “R7 in 1/8 inch” claim doesn’t apply to floor conduction between metal and plywood)

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Unique numerical values mentioned

• 1/8 inch thickness tied to Hushmat’s alleged R-value ~7 claim (influencer claim; disputed by creator)
• $400 for 50 sq ft mentioned as a Hushmat cost reference (approx.)
• R-value discussion at ~20°F: polyiso R-value per inch drops until it matches XPS around 20°F
• XPS compressive strength: 25 psi or 15 psi minimum (as cited by creator)
• Spray foam thickness: repeatedly referenced 1–2 inches, including ~1.5 inches in his rib-covering example
• Thermal bridging illustration:
  • wall assembly R20 with studs at R1 per inch, over 3 inches (illustrative numbers)

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Verdict / overall recommendation (based on the video)

For full-time living in a bus/rig, the creator’s recommendation is:

• Choose closed-cell polyurethane spray foam for walls/ceilings to control conduction and manage vapor.
• Use radiant barriers like Reflectix only where radiant blocking is actually dominant (windows, engine bay/firewall), not as a general replacement for true insulation.
• Be very cautious with Havelock wool unless proper secure placement and variable/intelligent vapor barrier design can be guaranteed.
• He strongly distrusts Hushmat’s high R-value marketing for subfloor use between the metal pan and plywood, and says you’re better off not paying for it for that purpose.

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Speaker breakdown

• Chuck Cass (primary speaker): provides the insulation philosophy framework, technical heat-transfer explanations, all product criticisms/praises (Reflectix, Havelock wool, Hushmat), and installation guidance (vapor barriers, thermal bridging, framing, windows, ventilation).