Signs of Carpet Beetles vs Moths: How to Tell What’s Damaging Your Clothes

Signs of Carpet Beetles vs Moths: How to Tell What’s Damaging Your Clothes

Finding holes in a favourite jumper or suit is frustrating, and it’s easy to assume “moths”. In reality, carpet beetles cause a huge share of fabric damage in UK homes. The fixes differ, so getting the ID right matters. This guide shows you how to tell carpet beetles from clothes moths by their damage, debris and life stages, and explains the best, science-backed way to stop it for good.

At ThermoPest we specialise in whole-room heat remediation for textile pests and other insects. The same professional equipment and controls used in bed bug heat treatment are highly effective against clothes moths and carpet beetles. Below, we outline the facts and practical steps you can take safely.

What people believe vs reality

• Belief: Any hole in knitwear = moths. Reality: Carpet beetle larvae often cause scattered, larger holes and leave bristly shed skins; moth larvae tend to create smaller, cleaner-edged holes with silk webbing.
• Belief: Seeing a beetle means you don’t have a textile pest. Reality: Adult carpet beetles are common around windows; it’s their larvae, hidden in wardrobes and skirtings, that eat fibres.
• Belief: A quick spray solves it. Reality: Eggs hidden deep in seams and under floors survive many DIY sprays; re-treatment is common.

Science‑backed signs: moths vs carpet beetles

Clothes moths (webbing and case‑bearing)

• Damage pattern: Clusters of small, clean-edged holes or grazed patches; often in seams, under collars, where fabric is undisturbed.
• Debris: Fine, sand-like frass (faeces) matching the fabric colour; silk webbing; small cigar-shaped larvae; papery cocoons.
• Larvae: Cream larvae with dark head; case-bearers drag a little portable case made of silk and fibres.
• Adults: Small, buff moths that avoid light, fluttering low in wardrobes and dark corners.
• Hotspots: Wardrobes, drawers, beneath furniture, along skirtings, stored textiles, wool rugs’ undersides.

Carpet beetles (varied, furniture, black)

• Damage pattern: Larger, irregular holes; bare patches where nap is stripped; damage at edges/under furniture and on natural-fibre mixes (wool, silk, hair, feathers, felt).
• Debris: Numerous cast larval skins (carrot-shaped, banded, with bristles) and gritty frass; less silk than moths.
• Larvae: Brown, tapered, bristly “woolly bears” that avoid light and hide in cracks.
• Adults: Small oval beetles often found at windowsills, attracted to light; adults don’t eat clothing.
• Hotspots: Carpet edges, under skirtings, floor voids, loft insulation with nest material, under sofas, airing cupboards.

Tip: Place white paper under a suspect shelf and tap garments; gritty frass, bristly skins (beetles) or silk webbing and tiny pellets (moths) will fall and help you confirm the culprit.

Common mistakes that prolong damage

• Relying on moth pheromone traps to solve a carpet beetle problem (they won’t work on beetles).
• Spraying visible adults but ignoring larvae and eggs in concealed cracks.
• Only washing at cool temperatures; many eggs/larvae survive below 50°C.
• Decluttering textiles without sealing bags first, spreading pests through the home.
• Missing structural sources: old bird nests, chimney breasts, loft insulation or stored natural stuffing.

Practical steps you can do safely

• Isolate and bag: Double-bag affected items before moving them. Label “treat” vs “clean”.
• Launder or heat-dry: Where care labels allow, wash at 60°C or tumble-dry on high for at least 30 minutes once core temperature is reached. For temperature guidance see what temperature kills bed bugs (lethal thresholds are similar for other insects).
• Freeze delicates: For heat-sensitive garments, freeze at −18°C for 72 hours, thaw, then repeat once (two cycles increase egg kill).
• Vacuum thoroughly: Use crevice tools along carpet edges, wardrobe floors, under skirtings, sofa bases; empty the vacuum outdoors immediately.
• Inspect and clean: Lift rug corners, check drawer runners, behind kickboards; wipe shelves and wardrobe seams. See our guidance on cleaning to avoid moving pests between rooms.
• Targeted monitoring: Use moth pheromone traps inside wardrobes only if you’ve confirmed moths; for beetles, place sticky monitors near light sources and windows to gauge adult activity and monitor your property after treatment.
• Prepare well for professionals: Open drawers, de-clutter floor areas, lift items off carpets so heat can circulate. Our checklist for preparing your home for treatment applies equally to moth and beetle heat work.

Why heat treatment is the superior solution

Chemicals struggle to reach eggs in dense textiles, voids and floor edges, and resistance is well documented in some moth populations. Whole-room heat, delivered professionally, overcomes these limits.

• No cold spots: Industrial heaters and high‑flow fans drive heat into wardrobes, carpet edges and voids. Technicians move items to expose hidden zones so there are no cool refuges.
• Sustained lethal temperature: We hold rooms at 55–60°C so heat penetrates garments, underlays and cracks long enough to kill eggs, larvae, pupae and adults.
• Sensors and monitoring: Multiple wireless probes track temperatures in the hardest places (drawer cores, carpet edges). Live data ensures targets are met before the heat cycle ends.
• All life stages killed: Eggs are the most heat‑tolerant; by sustaining temperature beyond their thresholds, complete knockdown is achieved in a single visit.
• Non-chemical and fast: No residues on clothing, minimal disruption, and rooms are usable once cooled.

If you’d like the technical overview, see our bed bug heat treatment process—the same physics and controls apply to moths and carpet beetles. For why this outperforms sprays, read why heat treatment works better than chemicals.

ThermoPest expertise

ThermoPest applies controlled heat for domestic wardrobes, rugs and upholstered furniture, and for complex commercial sites. Our commercial heat treatment for hotels and landlords is designed for rapid turnaround and audit trails, while our home service focuses on protecting cherished garments and preventing re‑introduction.

FAQ’S

Question: How can I tell if holes in my jumper are from moths or carpet beetles?

Answer: Look for the accompaniments, not just the holes. Moths leave fine, fabric-coloured pellets and silk webbing, and their larvae or cocoons may be in seams; carpet beetles leave numerous bristly, carrot-shaped cast skins and gritty frass with little or no silk. Moth damage often appears as clusters of small clean holes, while beetles cause larger irregular holes and bare patches, especially at edges and under furniture. A bright torch and a white paper “tap test” under garments can reveal the tell-tale debris; in professional practice, this simple check is often enough to confirm species.

Question: Do pheromone traps get rid of carpet beetles?

Answer: No—common wardrobe pheromone traps attract clothes moths only. Carpet beetles do not respond to moth lures, so those traps won’t reduce beetle larvae feeding on fibres. For beetles, sticky monitors near windows help track adult presence, but they are for monitoring, not control. In professional practice we pair monitoring with targeted vacuuming and heat to eliminate the larval source.

Question: Can washing or freezing save infested clothes?

Answer: Yes—if done correctly and safely for the fabric. Washables can be run at 60°C, or tumble-dried on high until the core of the item has been hot for at least 30 minutes; delicate items can be frozen at −18°C for 72 hours, thawed, then frozen again to improve egg kill. DIY attempts fail when temperatures aren’t sustained long enough, or when items are moved around unbagged and cross-contaminate other areas. Bag items before and after treatment; in professional practice we combine item-level deinfestation with room heat so no cold spots remain.

Question: Why do moth or beetle problems come back after spraying?

Answer: Survival of hidden eggs and larvae in voids, skirtings and deep textiles is the usual reason, combined with reintroduction from stored items or second-hand textiles. Sprays can’t reliably penetrate these protected areas, and some moth populations show reduced susceptibility to common actives. Whole-room heat holds lethal temperatures everywhere simultaneously, closing off refuges and preventing cold spots that let eggs survive. Keep a simple monitoring routine afterwards to catch any reintroduction early; in professional practice we always schedule follow-up checks.

Question: What temperature kills clothes moths and carpet beetles?

Answer: Lethal thresholds for insects are typically reached in the low-to-mid 50s °C when the exposure is sustained; professionals aim for 55–60°C throughout the room and contents to ensure eggs are also neutralised. Short, uneven heating leaves cold spots where life stages survive. For a broader explanation of thermal thresholds see what temperature kills bed bugs—the principle applies across species. In professional practice we verify temperatures at the hardest points with multiple sensors before ending the cycle.