HVAC Thermal Management & Insulation
H-O Products die-cuts and converts the thermal layer set inside packaged HVAC equipment: closed-cell vinyl nitrile, neoprene, and EPDM foam duct and plenum liners, anti-condensation panel liners, glass-fiber paper and mica heat-exchanger gaskets, refrigerant-line insulation parts, cabinet thermal-break pads, and the burner-adjacent insulation layers near the hot end of the appliance, built to your drawing.
Built for: rooftop units and air handlers fighting bypass heat gain and panel sweat, furnaces and unit heaters with combustion-side gasket and insulation duty, heat pumps and chillers with cold-line condensation control, and the cabinet thermal breaks that keep conditioned air from bleeding through sheet metal, with every standard cited by designation and every material value per the vendor TDS.
To insulate packaged HVAC equipment, work job by job from the airstream out. Duct and plenum liners: die-cut closed-cell vinyl nitrile foam (the elastomeric-insulation family framed by ASTM C534, with flame and smoke indices per ASTM E84 on the vendor TDS), neoprene foam, or EPDM sponge.
Anti-condensation liners: the same closed-cell families chosen for low water-vapor permeance (methods per ASTM E96 on the TDS), die-cut to cover the full cold surface. Heat-exchanger interface gaskets: ManniGlas® glass-fiber paper and mica sheet at the hot interfaces, BISCO® silicone foam where conformability matters at moderate temperatures (silicone grade TDSs commonly span about −55 to +200 °C).
Refrigerant-line parts: die-cut vinyl nitrile wraps, saddles, and grommets, with refrigerant and oil exposure checked per the vendor TDS compatibility tables. Cabinet thermal breaks: strips of polyimide foam, EPDM, or ArmaGel® aerogel blanket between panel skins and frames.
Burner-adjacent insulation: inorganic high-temperature families, glass-fiber paper and mica, with continuous-service classes from roughly 500 °C to above 900 °C depending on grade per the vendor TDS.
Material classes per the TDS; system standards by designation; final material selection should be validated in the application. See the quote form for ordering details.
System- and installation-level, by designation (the evaluation belongs to the customer's tested equipment or installation): NFPA 90A-context duct and plenum practice · AHRI equipment-rating programs · ASHRAE handbook design guidance.
Material-level, per the maker TDS: ASTM C534 (preformed flexible elastomeric cellular thermal insulation, the specification framing vinyl nitrile duct insulation) · ASTM E84 / UL 723 (surface burning characteristics; the 25/50 flame-spread and smoke-developed index pair) · ASTM E96 (water vapor transmission, the permeance number behind anti-sweat design) · ASTM C177 / C518 (thermal conductivity methods) · ASTM D1056 (cellular rubber classification) · UL 94 (flammability classes on the listed grades).
- Duct / plenum liner die-cuts: vinyl nitrile foam
- Economical cabinet insulation: neoprene foam / EPDM sponge
- Anti-sweat panel liners: closed-cell VN foam (permeance per ASTM E96 on the TDS)
- Heat-exchanger gaskets: ManniGlas® 1200 / mica sheet
- Conformable warm-side seals: BISCO® HT-870 silicone foam
- Refrigerant-line wraps & saddles: SBE41VN / SBE42VN
- Cabinet thermal breaks: polyimide foam / ArmaGel® HT
- Thin space-starved insulation: building / industrial aerogel grades
- Burner-adjacent layers: glass-fiber paper / phlogopite mica
- Electronics-side TIMs: see power-module thermal management
Where are you in the spec process?
This page serves engineers who already have insulation callouts on the drawing and engineers still deciding which family carries each job. Pick the path that matches where you are; you don't have to read the rest.
Send a drawing, get a quote
A vinyl nitrile thickness, a glass-fiber paper grade, an aerogel blanket gauge, a liner flat pattern, or a complete kiss-cut insulation kit on your drawing. Engineering reviews it against the maker TDSs and quotes it.
Skip to the quote form →Work the six jobs in order
Six numbered thermal jobs from the supply plenum out to the burner compartment, each with engineering context, the material families that commonly carry it, and exactly what to put on the drawing.
Start with the duct liner →
Where H-O parts do the work
Pick a job to see the exposure, the constraint, and the material families H-O converts for it.
Duct & plenum insulation die-cuts
Engineering context. Every packaged unit moves conditioned air through sheet metal that sits in unconditioned space: a rooftop supply plenum baking in summer sun, an air-handler casing in a 40 °C mechanical room, a unit-heater discharge above an unheated warehouse.
Uninsulated panels bleed capacity, and the loss shows up twice, once as energy and once as a rating: cabinet heat gain and leakage are part of how packaged equipment performs in AHRI-style rating programs, which is why production insulation is engineered as panel sets rather than field-wrapped rolls.
The factory version of this job is a kiss-cut kit: one liner per panel, cut to the stiffener pockets and fastener holes, applied in seconds on the line.
What H-O converts. Die-cut and kiss-cut closed-cell vinyl nitrile foam panel liners and plenum blankets in sheet thicknesses; neoprene foam and EPDM sponge liners where the chemistry or budget points that way; polyimide foam for weight- and space-constrained casings; and building and industrial aerogel grades where a thin section has to do a thick section's work. Liners ship flat on liner paper, with laminated facings or PSA where the assembly calls for it.
Material-family guidance. Closed-cell vinyl nitrile is the duct-liner default for a reason: it is the material family the ASTM C534 elastomeric-insulation specification frames [2], its thermal conductivity is reported per ASTM C177/C518 methods on the vendor TDS [1], and grades are available with the 25/50 flame-spread and smoke-developed indices per ASTM E84 testing reported on the vendor TDS [3], the index pair many duct and plenum specs call for.
Neoprene and EPDM closed-cell foams carry the same geometry at different chemistries, with service classes commonly in the −40 to roughly +93 °C (neoprene) and +121 °C (EPDM) bands per the grade TDSs. Where the casing wall is millimeters from the airstream, aerogel blanket buys the most thermal resistance per millimeter of any family on this page.
Duct and plenum practice at the installation level is framed by NFPA 90A-context code requirements, cited here by designation only: the installation evaluation belongs to the system designer, and the material indices belong to the tested grade per its TDS.
Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.
Panel flat patterns (DXF is ideal) with stiffener and fastener cutouts, target thickness or thermal-resistance note, the flame/smoke index requirement if the spec carries one (25/50 per ASTM E84, per the vendor TDS), facing or PSA preference, and quantities for prototype and production. "Recommend the family" is a valid callout.
Anti-condensation & anti-sweat liners
Engineering context. Condensation is the quiet warranty claim of cooling equipment. Any surface that runs below the local dew point sweats: the supply-air side of an uninsulated panel, the suction-line stub inside a control compartment, the underside of a drain pan in humid August air. The water finds electronics, rusts cabinets, soaks building insulation, and drips through ceiling tiles, and the field fix (wrap and tape) rarely survives the first service visit.
The engineered fix is a closed-cell liner that covers the entire cold surface with no gaps, because a 95-percent-covered cold panel still sweats along the missing five percent.
What H-O converts. Die-cut closed-cell vinyl nitrile anti-sweat liners for panels, drain-pan undersides, and valve compartments; SBE41VN and SBE42VN grade parts where a specified vinyl nitrile designation is already on the drawing; neoprene foam liners; and PSA-backed versions of all of the above, laminated in-house so the liner peels and sticks on the production line.
Material-family guidance. Anti-sweat design is a two-number problem. The first number is thermal: the liner has to be thick enough that its exposed surface stays above dew point, which falls out of the cold-side temperature, the design ambient and humidity, and the material's conductivity per ASTM C177/C518 on the TDS [1]. The second number is water-vapor permeance, per ASTM E96 methods on the vendor TDS [4]: a liner that lets vapor through eventually condenses against the cold metal it was protecting, soaks, and loses its insulating value.
Closed-cell vinyl nitrile carries both numbers in one material, which is why it dominates the job; open-cell foams are commonly unsuitable here regardless of their conductivity. Where the liner attaches with PSA, one sentence governs: adhesive performance depends on substrate, surface energy, temperature, exposure, dwell time, applied pressure, surface preparation, joint geometry, and the assembly process, and tape and adhesive selections should be validated in the application.
Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.
The cold-surface geometry and its operating temperature, design ambient and relative humidity (the dew-point inputs), full-coverage flat patterns including edges and penetrations, PSA preference and the substrate it bonds to (bare galvanized, painted, or powder-coated changes the answer), and quantities. If condensation has already appeared in the field, photos of the wet zones speed the review.
Heat-exchanger interface gaskets
Engineering context. Where a heat exchanger meets sheet metal, two requirements collide: the joint must seal (combustion products on one side, conditioned air on the other) and the gasket must hold its properties at the interface temperature, which ranges from warm-coil mild to flue-collar punishing.
A furnace heat-exchanger flange, a condensing secondary exchanger's transition, an inducer-blower mounting plate, and a coil-frame-to-casing joint are four versions of the same part: a gasket whose material family is chosen by the temperature at the bolt line, not the temperature on the nameplate.
What H-O converts. Die-cut ManniGlas® glass-fiber paper flange and collar gaskets, with ManniGlas® 1200 the workhorse grade; mica sheet gaskets where the joint runs hotter still or needs an inorganic barrier that contributes no fuel; BISCO® silicone foam and silicone sponge gaskets, including HT-870 Soft, for warm-side joints that need conformability at low closure force; and laminated constructions that put a glass-fiber face on a compressible body for joints that need both.
Material-family guidance. Sort the joints by temperature band, per the vendor TDS for each grade. Silicone foam and sponge grades commonly carry about −55 to +200 °C service classes and seal at sheet-metal closure forces, with compression behavior classified per ASTM D1056 [6] and UL 94 classes on the listed grades per their TDSs [5]; they own the warm side.
Glass-fiber paper takes over where elastomers age out: ManniGlas® grades carry continuous-use ratings in the roughly 540 to 760 °C class depending on grade per the vendor TDS, in thin, die-cuttable sheets.
Mica goes where the joint is hottest or where an arc- or flame-adjacent barrier function rides along, with muscovite and phlogopite grades stable to service classes above 900 °C per grade TDSs. The deep treatment of the inorganic barrier families lives on the arc flash & fire protection page; this job is their HVAC flange duty. Compression, flange flatness, and bolt-pattern geometry decide whether a 0.4 mm paper or a 3 mm cushioned laminate seals the joint; send the flange drawing rather than guessing.
Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.
Flange geometry with bolt pattern (DXF or a dimensioned sketch), the measured or design temperature at the joint, what the gasket seals against (flue products, conditioned air, condensate), required thickness or compression note, and quantities. If a current gasket fails in service, a photo of the failed part tells the review more than a paragraph.
Refrigerant-line insulation parts
Engineering context. Inside the cabinet, refrigerant lines need insulation in pieces, not in rolls. A suction line running below dew point sweats onto whatever sits beneath it; a hot-gas line radiates into a compartment that was supposed to stay cool; a TXV bulb needs thermal contact in one spot and isolation everywhere else; and every line that passes through sheet metal needs a grommet that insulates, seals, and forgives vibration at the same time.
Field insulation handles the long runs; the factory problem is the fittings, penetrations, clamps, and short stubs where continuous tube insulation cannot go, which is exactly where parts live.
What H-O converts. Die-cut closed-cell vinyl nitrile line wraps, saddle pads, valve-body covers, and panel-penetration grommets, with SBE41VN and SBE42VN the commonly specified grades; neoprene foam clamp cushions and isolation pads at line supports; and building and industrial aerogel grades for the tight spots where a 3 mm blanket has to behave like a 13 mm tube section. Kiss-cut wrap kits ship flat with sealed edges, one set per unit.
Material-family guidance. The selection logic mirrors Job 2: closed-cell construction for the vapor barrier (permeance per ASTM E96 on the TDS [4]), thickness from the dew-point calculation, and the elastomeric-insulation framing of ASTM C534 for the vinyl nitrile family [2]. Two cautions are specific to this job.
First, chemistry: parts near service valves, Schrader cores, and compressor fittings see refrigerant and lubricant mist, and elastomeric foams respond differently to POE and PAG oils and to individual refrigerants; check exposure per the vendor TDS compatibility tables rather than assuming a family-level answer, and note that materials in contact with the refrigerant circuit itself belong to the sealing conversation on the parent thermal management & insulation page's sibling applications.
Second, mechanics: a line clamp that crushes its insulation creates a bare conduction bridge and a sweat spot, so saddle pads at clamps are commonly a firmer grade than the wrap itself, with compression classes per ASTM D1056 on the grade TDS [6]. Line-support vibration duty (clamp cushions doing double work) crosses into the vibration, shock & acoustic family.
Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.
Line diameters and operating temperatures (suction, liquid, hot-gas), the wrap, saddle, or grommet geometry, refrigerant and lubricant in the system for TDS compatibility screening, panel thickness at penetrations, and quantities. A photo of the routed lines in the cabinet is often the fastest way to scope a wrap kit.
Cabinet thermal breaks
Engineering context. A double-wall HVAC cabinet insulates beautifully everywhere except where its skins touch: door frames, panel flanges, stiffeners, and fastener lines form metal bridges that carry heat straight past the insulation. The signature is visible on humid days as sweat lines tracing the internal frame on the cabinet exterior, and it shows up in test data as a higher casing heat-transfer factor than the insulation thickness predicted.
The fix is a thermal break: a strip of low-conductivity material between the inner and outer skins at every contact line, specified like a structural part because it also carries the panel's clamping load.
What H-O converts. Die-cut and slit thermal-break strips and pads of polyimide foam (light, dimensionally stable, with a wide service window per the vendor TDS), premium closed-cell EPDM and EPDM sponge where the break doubles as a compression seal (the RE-series grades step through firmness classes per ASTM D1056 on their TDSs), and ArmaGel® aerogel blanket from the aerogel family where the bridge is severe and the available gap is thin. Strips ship cut to the frame layout, with PSA backing where the line wants peel-and-stick placement.
Material-family guidance. A thermal break is specified by three numbers: conductivity (per ASTM C177/C518 on the TDS [1]), compression behavior under the fastener and flange load (a break that crushes flat insulates like the metal it replaced), and the service-temperature window. Foam breaks suit door frames and panel flanges where the load spreads; aerogel earns its cost where geometry is starved, buying the most temperature drop per millimeter of thickness of any family here.
Condensation marks the failure threshold: run the same dew-point arithmetic as Job 2 on the bridge path, because the first symptom of an undersized break is a sweat line, not an energy bill. For PSA-placed strips, the standing sentence applies: adhesive performance depends on substrate, surface energy, temperature, exposure, dwell time, applied pressure, surface preparation, joint geometry, and the assembly process, and adhesive selections should be validated in the application.
Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.
The frame or flange cross-section at each bridge line, clamping load or fastener torque, interior and ambient design temperatures with humidity, available gap thickness, and the strip layout (lengths and widths, or a DXF of the frame). If the symptom is field sweat lines, photos locate the bridges faster than drawings.
Burner-adjacent & combustion-side insulation
Engineering context. Around the burner compartment, the materials conversation changes entirely: organic foams have no business there, and the layer set becomes inorganic. A furnace vestibule panel that shields wiring from radiant heat, a burner-box liner, a sight-glass gasket, an inducer housing seal, and the standoff washers behind a hot panel are all parts whose families are chosen from the high-temperature end of the catalog, with continuous-service classes from roughly 500 °C to above 900 °C depending on grade per the vendor TDS.
The same parts usually carry a second duty as flame-adjacent barriers, which is why their documentation matters as much as their dimensions.
What H-O converts. Die-cut ManniGlas® glass-fiber paper liners, shields, and gaskets (grade 1200 and its siblings, with continuous-use ratings in the roughly 540 to 760 °C class depending on grade per the vendor TDS); mica sheet barriers and washers, with phlogopite grades for the hottest positions; silicone-coated fiberglass fabric parts by family designation where a flexible, abrasion-tolerant hot-side cloth suits the joint, properties per the vendor TDS; and ArmaGel® HT aerogel blanket (rated to 650 °C per its TDS) where a thin blanket has to hold back a hot wall.
Material-family guidance. Choose by temperature class first, then by mechanical role, always per the grade TDS. Glass-fiber paper is the converter's workhorse at the hot end: thin, die-cuttable, inorganic, and economical enough to use generously as radiant shields and gasket stock.
Mica adds rigidity and the highest temperature ceilings of this page, and it contributes no fuel to a flame scenario, which is why the same grades serve arc- and fire-barrier duty elsewhere in the estate; the dedicated treatment of fire-barrier layering, flame-face logic, and the documentation that travels with it lives on the arc flash & fire protection page.
Aerogel blanket handles the in-between: hotter than elastomers tolerate, thinner than traditional batt allows, with conductivity per ASTM C177-class methods on its TDS [1]. Two framing rules keep drawings honest. Flammability indices and classes (ASTM E84 pairs, UL 94 classes) belong to the listed material grade per its TDS [3] [5]; and appliance-level safety evaluations belong to the customer's tested equipment, so this page cites those programs by designation only.
H-O supplies the converted layers and the TDS documentation behind them.
Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.
Part geometry, the measured or design temperature at the part location (not the flame temperature), whether the part seals, shields, or insulates, any flammability class or index the spec carries (per the vendor TDS), and quantities. If the part replaces a failed one, send the failed part or its photo; the failure mode usually names the right family.
The decisions that drive an HVAC thermal-insulation spec
Thermal-insulation and anti-condensation parts are chosen in order: what the part must stop, at what temperature, and against what moisture.
Match the part to the heat path and the dew-point risk first, then to the flame class and documentation the design review asks for. Duct, plenum, and cabinet parts carry their own ratings per grade TDS.
Show all 5 selection factors tap to expand
Specification Tools
Two tools to take you from "we're building a packaged unit" to here's the thermal material checklist for the drawing set: a job-driven checklist builder that assembles the layer list with its what-to-send notes, and a side-by-side comparison of every thermal family on this page.
1. HVAC thermal-job checklist builder
Check the jobs your unit carries. The builder assembles the corresponding material layers into a checklist with the family, what to send with the drawing, and the citation language (material classes and indices per the vendor TDS; system and installation standards by designation). The default selection below is pre-built for a typical packaged cooling unit; every layer is also printed in the material reference section, so nothing here exists only behind a script.
Thermal checklist: 3 layers selected
Each checked job adds its layer below. The list is the starting bill of materials for the engineering review, not a certification: material indices and classes come from the grade TDS, and system and installation standards are cited by designation with the evaluation belonging to the customer's tested equipment.
- Duct / plenum liners: closed-cell vinyl nitrile foam (ASTM C534 family)Send: panel flat patterns, thickness or R note, flame/smoke index requirement (per vendor TDS). Cite: ASTM C534; E84 indices per the grade TDS.
- Anti-sweat liners: closed-cell VN foam, full-coverage die-cutsSend: cold-surface temps, design ambient and humidity, full-coverage patterns, PSA substrate. Cite: ASTM E96 permeance and C177/C518 conductivity per the TDS.
- Line parts: VN wraps, saddles, and grommets (SBE41VN/42VN)Send: line sizes and temperatures, refrigerant and lubricant for TDS compatibility screening, penetration details. Cite: compatibility per vendor TDS tables.
2. Side-by-side: HVAC thermal family comparison matrix
Every family called out on this page, with construction, the property that drives its selection, the methods its TDS cites, and the jobs it serves. Click a column header to sort. Click any material name to jump to its reference entry. Values are family-level descriptors; per-grade numbers live on the maker TDSs.
| Material | Construction | Service band (per TDS) | Methods on the TDS | Jobs here | |
|---|---|---|---|---|---|
| Closed-cell elastomeric foams (the airstream envelope) | |||||
| Vinyl Nitrile Foam (ENSOLITE® family; SBE41VN / SBE42VN)ASTM C534 elastomeric family | Closed-cell VN foam | Approx. −40 to +104 °C class | C534 framing; E84 indices; E96; D1056 | Ducts, anti-sweat, lines | |
| Neoprene FoamClosed-cell sheet grades | Closed-cell CR foam | Approx. −40 to +93 °C class | ASTM D1056 classes per grade | Liners, clamp cushions | |
| EPDM Sponge & Premium Closed-Cell EPDM (RE-series)Compression-class steps | Closed-cell EPDM | Approx. −40 to +121 °C class | ASTM D1056 classes per grade | Liners, thermal breaks | |
| Specialty insulation (thin, light, or wide-window) | |||||
| Polyimide FoamLightweight open structure | Polyimide cellular | Wide window per vendor TDS | Thermal & flammability per TDS | Casings, thermal breaks | |
| Aerogel Blanket (ArmaGel® HT; building/industrial grades)Most resistance per mm | Silica aerogel in fiber web | HT grade to 650 °C per TDS | ASTM C177-class; E84 where reported | Thin spots, breaks, hot walls | |
| Hot-interface and inorganic families (the combustion side) | |||||
| Glass-Fiber Paper (ManniGlas® 1200 and siblings)Inorganic gasket & shield stock | Nonwoven glass paper | Approx. 540–760 °C class by grade | Continuous-use rating per vendor TDS | HX gaskets, burner shields | |
| Mica Sheet (muscovite / phlogopite grades)Hottest positions on this page | Mica paper laminate | Service classes above 900 °C per grade TDS | Per-grade data per vendor TDS | HX flanges, flame-adjacent | |
| Silicone Foam & Sponge (BISCO® HT-870 and siblings)Conformable warm-side seals | Cellular silicone | Approx. −55 to +200 °C class | ASTM D1056; UL 94 per grade TDS | Warm HX joints, breaks | |
| PSA-Laminated Liner Constructions (VN / neoprene + adhesive)Peel-and-stick production parts | Foam + PSA laminate | Foam band; adhesive band per tape TDS | Foam methods + adhesive data per TDS | Anti-sweat, line wraps | |
Skip ahead and request your engineering review now
If your drawing set already calls out a vinyl nitrile thickness, a glass-fiber paper grade, an aerogel gauge, or a liner flat pattern, send it over for review against the TDSs and the standards language.
HVAC thermal-insulation failures you can prevent at spec
An under-specified insulation part shows up as sweating ducts, hot cabinets, or a plenum part that fails the air-handling flame rating — all preventable in the callout.
The equipment’s air-handling and flame ratings belong to the maker’s tested assembly. A converter-side part that wicks moisture or misses its plenum flame class puts that rating at risk.
Show all 5 failure modes tap to expand
1. Open-cell foam on a cold refrigerant line
Fix — use closed-cell, low-absorption foam (ASTM C534 class per TDS); open-cell wicks condensate and drips.
2. Elastomer at a heat-exchanger or burner-adjacent interface
Fix — move to mica or MannIGlas® glass-fiber where temperatures retire elastomers.
3. Missing plenum flame rating
Fix — specify UL 94 / air-plenum-rated grades per TDS so the part clears the air-handling review.
4. Thermal break too soft under load
Fix — match foam density and compression (D1056 class per TDS) so the break holds without crushing.
5. Field-cut insulation with gaps
Fix — die-cut duct and plenum parts to the drawing so seams close and thermal bridging is controlled.
Material reference
Detailed family-level notes for the eight thermal families referenced on this page: the closed-cell elastomeric foams (vinyl nitrile, neoprene, EPDM) that line the airstream and fight condensation, the specialty insulations (polyimide foam, aerogel blanket) for thin and wide-window duty, and the hot-interface families (glass-fiber paper, mica, cellular silicone) at the combustion end.
Values are per the maker TDS on file for each grade with the method named; installation and equipment standards are cited by designation only, with any evaluation belonging to the customer's tested system.
H-O die-cuts, kiss-cuts, slits, laminates, and kits every family to drawing.
Closed-Cell Vinyl Nitrile Foam (ENSOLITE® family; SBE41VN / SBE42VN)Duct liners, anti-sweat liners, line wraps · ASTM C534 family framing · E84 indices & E96 permeance per grade TDS
Closed-cell structure is the point: the foam is its own vapor retarder, with permeance per ASTM E96 on the TDS. Check refrigerant and lubricant exposure per the vendor TDS compatibility tables for parts near service fittings. Final material selection should be validated in the application.
Neoprene Closed-Cell FoamEconomical liners & clamp cushions · ASTM D1056 classes per grade TDS
When a neoprene part sits near refrigerant fittings or compressor oil mist, screen the exposure per the vendor TDS compatibility tables, same as the vinyl nitrile rule.
EPDM Sponge & Premium Closed-Cell EPDM (RE-Series)Liners that double as seals; thermal-break strips · ASTM D1056 compression classes per grade TDS
Pick the firmness class from the real closure force, not the catalog default: a thermal break that crushes flat conducts, and a seal that fights the latch leaks.
Polyimide FoamLight, wide-window casing insulation & thermal breaks · properties per vendor TDS
Polyimide foam is a specialty answer at a specialty price; the review pairs it with the job only when the commodity families genuinely fall short.
Aerogel Blanket (ArmaGel® HT; Building / Industrial Grades)The most thermal resistance per millimeter on this page · ASTM C177-class methods; HT grade to 650 °C per TDS
Aerogel dust is part of converting it; H-O handles edge sealing and facing lamination so assembly lines do not have to.
Glass-Fiber Paper (ManniGlas® 1200 and Siblings)Hot-interface gaskets & radiant shields · continuous-use ratings roughly 540–760 °C class by grade per vendor TDS
Thin paper seals flat, machined flanges; warped or rough flanges want a cushioned laminate construction. Send the flange drawing and the joint temperature, and the review picks the construction.
Mica Sheet (Muscovite / Phlogopite Grades)The hottest positions on this page · service classes above 900 °C per grade TDS · inorganic barrier duty
Mica earns its keep only if the part survives assembly handling: edges, tabs, and tolerances come off the drawing, not the shear. Rigid versus flexible construction is a review decision; send the geometry.
Silicone Foam & Sponge (BISCO® HT-870 and Siblings)Conformable warm-side sealing · about −55 to +200 °C class per grade TDS · UL 94 classes on listed grades
Silicone buys temperature endurance and compression-set resistance at a silicone price; let the joint temperature and flame-class requirement, per the grade TDS, make the call against EPDM.
HVAC thermal materials: engineer-grade FAQ
Ten of the questions we hear most from RTU, furnace, heat-pump, and air-handler teams. If your question isn't here, send a drawing or call, engineering picks up.
Which closed-cell foams are commonly for duct and plenum insulation inside HVAC equipment?
Closed-cell vinyl nitrile is the default: it is the elastomeric-insulation family framed by ASTM C534, with thermal conductivity per ASTM C177/C518 and flame and smoke indices per ASTM E84 reported on the vendor TDS for the rated grades. Neoprene foam and EPDM sponge carry the same liner geometry at different chemistries and price points, with EPDM favored on weather-exposed rooftop casings.
Polyimide foam and aerogel blanket take the thin, light, or wide-temperature exceptions. All of them ship as or kiss-cut panel sets, cut to stiffener pockets and fastener holes. [2]
How do I stop condensation on cold panels, drain pans, and refrigerant lines?
Solve two numbers and one coverage rule. Thickness comes from the dew-point calculation: the liner's exposed surface must stay above the dew point set by your design ambient and humidity, using the conductivity per ASTM C177/C518 on the TDS. Permeance comes from ASTM E96 data: a vapor-open liner eventually soaks against the cold metal and quits insulating, which is why closed-cell construction matters more than raw R-value here.
The coverage rule: die-cut the liner to cover the entire cold surface, edges and penetrations included, because the bare strip is where the sweating relocates. [4]
Do these materials carry a 25/50 flame and smoke rating?
Grades are available with 25/50 flame-spread and smoke-developed indices per ASTM E84 testing reported on the vendor TDS, and the index pair belongs to the tested material grade at its tested thickness, not to H-O and not to your equipment. Duct and plenum installation requirements (NFPA 90A-context code practice) are cited by designation only: whether a given installation requires the indices, and whether the equipment meets its own listing requirements, belongs to the system designer and the tested equipment.
Name the index requirement on the drawing and the review confirms a grade whose TDS carries it. [3]
What gasket goes between a heat exchanger and the cabinet panel?
Sort by the temperature at the bolt line, per the grade TDSs. Warm joints (blower mounts, access panels) suit cellular silicone, which seals at sheet-metal closure forces with about −55 to +200 °C class TDS service bands. Hot flanges move to glass-fiber paper such as ManniGlas® grades, with continuous-use ratings in the roughly 540–760 °C class by grade per the vendor TDS. The hottest and flame-adjacent positions go to mica.
Flange flatness decides construction: thin paper for flat machined flanges, a cushioned laminate for stamped sheet metal. [6]
What insulation survives next to the burner or flue?
The inorganic families: glass-fiber paper (continuous-use ratings in the roughly 540–760 °C class by grade per the vendor TDS), mica sheet (phlogopite service classes above 900 °C per grade TDSs), silicone-coated fiberglass fabrics by family designation, and ArmaGel® HT aerogel blanket (rated to 650 °C per its TDS) where a thin blanket has to insulate a hot wall.
Specify from the measured temperature at the part location, not the flame temperature, and keep appliance-level safety evaluations with the tested equipment, cited by designation.
The fire-barrier layering logic lives on the arc flash & fire protection page.
What is a cabinet thermal break, and which materials work?
A strip of low-conductivity material interrupting the metal path between a cabinet's inner and outer skins at frames, flanges, and stiffeners, where conduction bypasses the insulation and paints sweat lines on humid days. It is specified by three numbers: conductivity (ASTM C177/C518 per TDS), compression behavior under the clamping load (a crushed break conducts), and service-temperature window.
EPDM strips suit breaks that double as seals; polyimide foam suits light, stable, wide-window duty; aerogel blanket handles severe bridges in thin gaps. [1]
Can H-O supply insulation parts with pressure-sensitive adhesive backing?
Yes: liners, breaks, wraps, and gaskets laminate in-house to pressure-sensitive adhesive systems and ship as peel-and-stick parts on liner. The standing caution applies in full: adhesive performance depends on substrate, surface energy, temperature, exposure, dwell time, applied pressure, surface preparation, joint geometry, and the assembly process, and adhesive selections should be validated in the application.
Tell the review what the part sticks to (bare galvanized, painted, powder-coated) and the temperature it lives at; powder coat in particular is a low-surface-energy substrate that changes the adhesive answer.
Are these materials compatible with refrigerants and POE or PAG oils?
Per the vendor TDS compatibility tables, case by case, and that phrasing is deliberate: elastomeric foams respond differently to individual refrigerants and to POE and PAG lubricants, and a family-level yes would be wrong somewhere. Parts on this page see incidental exposure (mist near fittings, a weep at a service valve), which the tables screen quickly when you name the refrigerant and oil on the RFQ.
Gaskets that live in contact with the refrigerant circuit, compressor flanges and the like, are a different specification problem with their own material families and their own page in the estate.
Does H-O certify these materials or the equipment they go into?
No. H-O Products is an ISO 9001:2015 certified organization, and that is the only certification H-O holds. Material properties, flame and smoke indices, and flammability classes belong to the source maker's listed grade per its TDS; equipment listings and installation compliance belong to the customer's tested system. What H-O supplies is the converted part, the TDS documentation behind it, and lot-code material traceability, which is exactly what a design review wants from the converter in the chain.
What should I put on the drawing set so the quote comes back right the first time?
By job: for duct and plenum liners, the panel flat patterns, thickness or thermal-resistance note, and any flame/smoke index requirement; for anti-sweat parts, the cold-surface temperature, design ambient and humidity, and PSA substrate; for heat-exchanger gaskets, the flange drawing with bolt pattern and the joint temperature; for line parts, line sizes, temperatures, and the refrigerant and oil for TDS screening; for thermal breaks, the bridge cross-section, clamping load, and gap; for burner-adjacent parts, the measured temperature at the part location.
Plus quantities for prototype and production. "Recommend the family" is a valid callout: that is what the engineering review is for.
Glossary: terms used on this page
Quick reference for the insulation, condensation, and hot-interface terminology used throughout. Each entry links to the relevant standard or test method where applicable.
Closed-cell foam
Cellular material whose cells are sealed from one another, so the foam resists water and vapor uptake and acts as its own vapor retarder. The structural reason vinyl nitrile, neoprene, and EPDM carry the anti-condensation jobs on this page; open-cell foams are commonly unsuitable for cold-surface duty regardless of conductivity.
Thermal conductivity (k-value)
The rate at which a material conducts heat per unit thickness, reported per ASTM C177 or C518 methods [1] on the maker TDS at stated mean temperatures. Lower is better for insulation; aerogel blanket carries the lowest values on this page.
R-value (thermal resistance)
Thickness divided by conductivity: the resistance of the installed layer rather than the material property. Two liners with the same k-value differ in R by their gauge, which is why drawings should carry either a thickness or an R note, not a bare material name.
Water-vapor permeance (ASTM E96)
The rate at which water vapor passes through a material, per ASTM E96 methods [4] on the TDS. The second number of anti-sweat design: a low-permeance liner keeps vapor from reaching and condensing on the cold metal behind it.
Dew point & anti-sweat design
The temperature at which the local air's moisture condenses. Any surface below it sweats, so anti-sweat liners are sized to hold their exposed surface above the dew point set by the design ambient and humidity, with full coverage of the cold surface as the non-negotiable rule.
ASTM C534 (by designation)
The standard specification for preformed flexible elastomeric cellular thermal insulation, per [2]: the family framing behind closed-cell vinyl nitrile duct and line insulation. Cited by designation; per-grade conformance statements live on the vendor TDS.
ASTM E84 / 25-50 indices (per the grade TDS)
The surface-burning test (also designated UL 723) reporting a flame-spread index and a smoke-developed index, per [3]. "25/50" names the index pair many HVAC specs require. The indices belong to the tested material grade at its tested thickness per the vendor TDS; installation requirements are the system designer's call.
UL 94 (per the grade TDS)
The flammability classification for plastic materials (HB, V-2, V-1, V-0, 5V classes), per [5]. The class belongs to the listed material grade per its TDS at the tested thickness; it is a material property, not an equipment listing.
Thermal bridge / thermal break
A bridge is a conductive path (frame, flange, stiffener, fastener line) that carries heat past the insulation; a break is the low-conductivity strip that interrupts it while carrying the joint's mechanical load. The field signature of a missing break is a sweat line tracing the internal frame on humid days.
Aerogel blanket
Silica aerogel carried in a flexible fiber web: the most thermal resistance per millimeter of any family on this page, with conductivity per ASTM C177-class methods and, on the HT grade, a 650 °C rating per its TDS. Used here for severe bridges, thin gaps, and hot walls.
Compression set (ASTM D1056 context)
Permanent deformation after sustained compression, reported within the cellular-rubber classification of ASTM D1056 [6] on the grade TDSs. Decides whether a clamped liner, break, or gasket still does its job years into service.
Kiss-cut
A that cuts through the material but not its release liner, so a multi-part liner kit peels part by part on the assembly line in placement order. The production format for PSA-backed liner sets and wrap kits, run on CNC knife and flatbed die-cutting equipment.
Last updated · Reviewed by H-O Products engineering (ISO 9001:2015 certified converter, Winsted, CT).
Standards, test methods & technical references
The standards, test methods, and maker technical data sheets cited throughout this page, listed by name and designation only. System and installation standards are cited by designation: they evaluate equipment and installations, and the evaluation belongs to the customer's tested design. Standards editions current as of June 2026; verify against the publishing body before final spec.
H-O converts materials tested to the material-level methods on the source maker's TDS; H-O does not certify systems or independently certify materials unless explicitly stated on the quote.
[1] ASTM C177 / C518
Standard test methods for steady-state heat flux and thermal transmission properties (guarded hot plate and heat flow meter respectively): the methods behind the thermal-conductivity values on the foam, blanket, and aerogel TDSs cited on this page. Published by ASTM International; cited by designation, by name only.
[2] ASTM C534 (by designation)
Standard specification for preformed flexible elastomeric cellular thermal insulation in sheet and tubular form: the specification framing the closed-cell vinyl nitrile family on this page. Per-grade conformance statements belong to the vendor TDS. Published by ASTM International; cited by designation, by name only.
[3] ASTM E84 / UL 723 (per the grade TDS)
Standard test method for surface burning characteristics of building materials, reporting the flame-spread and smoke-developed indices (the "25/50" pair many HVAC specs require). The indices attach to the tested material grade at its tested thickness per the vendor TDS; installation requirements belong to the system designer. Published by ASTM International and UL; cited by designation, by name only.
[4] ASTM E96
Standard test methods for gravimetric determination of water vapor transmission rate of materials: the permeance number behind anti-condensation liner selection. Reported on the closed-cell foam TDSs with the method named. Published by ASTM International; cited by designation, by name only.
[5] UL 94 (per the grade TDS)
Standard for tests for flammability of plastic materials for parts in devices and appliances. Classes (HB through V-0 and 5V) attach to the listed material grade at the tested thickness per the maker TDS; they are material properties, not equipment listings. Published by UL; cited by designation, by name only.
[6] ASTM D1056
Standard specification for flexible cellular materials, sponge or expanded rubber: the classification system behind the compression classes on the vinyl nitrile, neoprene, EPDM, and silicone grade TDSs. Published by ASTM International; cited by designation, by name only.
[7] ASHRAE handbook & AHRI / NFPA 90A context (by name)
The ASHRAE handbook series (HVAC systems and equipment design guidance), AHRI equipment-rating program context, and NFPA 90A duct and plenum installation practice, referenced on this page by name and designation only as the design framework the customer's equipment answers to. Ratings, listings, and installation compliance belong to the tested equipment and its installation, not to component materials.
Updated . Standards editions current at publication; verify against the publishing body before final spec. H-O converts materials tested to the methods cited; H-O does not certify systems. Lot-specific documentation available on request.
Get an HVAC thermal-materials engineering quote
Send a drawing set, BOM, or panel layout. We typically respond within one business day with a material recommendation, prototype lead time, and TDS verification against your temperatures, dew-point inputs, index requirements, and standards language.
See also: related H-O application pages
Engineering content for the adjacent thermal and HVAC sub-applications, the parent application, and the owning industry hub. Each page covers material selection, failure modes, and converter-side process detail for its application family.
Parent application
Thermal management & insulation
The cross-industry thermal overview: TIMs, spreaders, insulation, and barrier families, with the selection logic this page's jobs draw from.
Read the page
Industry hub
Industrial HVAC
The full HVAC application family: sealing, vibration, thermal, electrical insulation, fire protection, and assembly materials from one directory.
Read the page
Sibling sub-application
Power-module thermal management
The TIM playbook for the electronics this page leaves out: VFD heat sinks, control boards, and the gap pads and graphite between them.
Read the page
Sibling sub-application
HVAC electrical insulation & EMI
Dielectric barriers and EMI parts for HVAC control boards, VFDs, and electrical panels.
Read the page
Sibling sub-application
HVAC fire & high-temp protection
High-temperature and flame-resistant barriers for HVAC heat sources and electrical compartments.
Read the page
Sibling sub-application
Smart HVAC, IoT & electronics
Thermal, sealing, and dielectric parts for HVAC sensors, controllers, and connected IoT modules.
Read the page
Sibling sub-application
Arc flash & fire protection
The dedicated treatment of the mica, glass-fiber, and fire-barrier families this page's burner-adjacent job places in the appliance.
Read the page
Sibling sub-application
Vibration, shock & acoustic
Compressor mounts, fan isolation, and the clamp cushions whose thermal cousins appear in this page's refrigerant-line job.
Read the page
Application overview
Engineered sealing & gasketing
The sealing-first view of the gaskets, liners, and breaks that do double duty on this page.
Read the page
Send the drawing set for your unit's thermal layers
Liners, anti-sweat parts, hot-interface gaskets, line kits, breaks, and burner-adjacent layers, in Winsted, Connecticut with material traceability and lot-code TDS records. Typical response in one business day.
Material data & standards. All thermal, permeance, compression, temperature, and flammability values on this page are taken from the source maker's technical data sheets with the method named (ASTM C177/C518 thermal methods, ASTM E96 water-vapor methods, ASTM E84 surface-burning indices, ASTM D1056 cellular classes, UL 94 classes per the listed grade TDSs).
Specification, equipment, and installation standards (ASTM C534, NFPA 90A context, AHRI programs, ASHRAE guidance) are cited by designation or by name only: they frame designs and installations, the evaluation belongs to the customer's tested equipment, and the materials on this page support designs evaluated to them.
Refrigerant and lubricant compatibility is determined per the vendor TDS compatibility tables, case by case. Performance depends on grade, geometry, compression, adhesive system, and environment; final material selection should be validated in the application. H-O converts materials; H-O does not design HVAC systems, run dew-point or load calculations of record, or certify equipment, and does not independently certify materials against the standards unless explicitly stated on the quote.
Verify against the maker TDS and your equipment-level evaluation plan.
Conversion scope. H-O and converts sheet, roll, and blanket stock to drawing in Winsted, Connecticut: die-cut and kiss-cut liners, gaskets, and break strips on flatbed die-cutting and CNC knife equipment, slit strip stock, waterjet-cut thick and aerogel sections, laminations including PSA backing and faced constructions, and kitted insulation sets, with material traceability and lot-code TDS records. H-O does not mold or extrude in-house; molded or extruded profiles are coordinated through a partner network.
Lead-time and MOQ details are in the quote form above. Renderings and diagrams on this page are representative illustrations, not product photographs.