Key takeaways

  • Lice and their eggs die at sustained temperatures above roughly 130°F (54°C).
  • A home dryer on its highest heat setting clears that, so run the load on high for at least 20 minutes, and closer to 30 for bulky items.
  • The heat does the killing, not the soap. If an item cannot be washed, a dry-only run on high still works.
  • Only launder what touched the head in the two days before treatment. Lice die within a day or two off a scalp, so the whole house does not need stripping.
  • For anything that cannot take heat, seal it in a plastic bag for two weeks and be done with it.

What’s in this guide

A dryer needs to hold sustained heat above about 130°F (54°C) to kill head lice and their eggs, and the practical way to get there is the highest heat setting for 20 to 30 minutes. That is the same threshold behind the CDC’s laundry advice for lice, which pairs a 130°F hot water wash with a high heat drying cycle.

The good news for anyone who just got the note home from school this August: your dryer already does this. You do not need a special appliance, a sanitize cycle, or a bottle of spray.

What temperature kills lice and their eggs?

Sustained exposure above roughly 130°F kills both crawling lice and the nits glued to hair shafts. Adult lice die quickly at that temperature. Eggs are the hardier of the two, which is why time at temperature matters more than hitting a single peak number.

Lice are built for a narrow comfort zone. They live on a human scalp at close to body temperature and they cannot regulate their own, so anything well above or well below that range is fatal within minutes. Heat is the reason a dryer works and the reason a cold wash does almost nothing.

Keep in mind that 130°F is the temperature the item needs to reach, not just the air passing by it. A thick hoodie balled up in the middle of a full drum can stay cool for a surprisingly long time.

Does a home dryer actually get that hot?

Yes. On the high or cotton setting, most residential dryers run drum air in the range of about 135°F to 150°F, and the air coming off the heating element is hotter still. Medium or permanent press typically lands closer to 125°F to 135°F, and low or delicate can sit under 120°F.

That spread is the whole reason the setting matters. High heat gives you margin. Low heat may or may not clear the threshold, and “may or may not” is not what you want when you are trying to end this in one round.

If your dryer has a sanitize cycle, it holds a higher temperature for a validated stretch and will absolutely do the job. It is more heat than lice require, and it is harder on fabric, so treat it as optional rather than necessary.

One more thing worth knowing about how these machines behave: sensor dry cycles stop when the load reads dry, which can be well before your 20 minutes of hot exposure are up. Use a timed dry so you control the clock. We got into similar dryer-heat territory when working out whether a backpack can survive the washer and dryer, and the same rule applies here.

How long should you run the dryer?

Twenty minutes on high heat is the standard recommendation, and it is worth counting that time from when the items are already hot and dry, not from when you press start. Damp laundry spends its first stretch of the cycle evaporating water, which holds the fabric temperature down. Wet clothes essentially cool themselves until the moisture is gone.

For pillows, comforters, plush toys, and anything thick, give it 30 minutes. Dense items take longer for heat to reach the center.

Do not overload the drum. A packed dryer tumbles poorly, and items in the middle of a tight load can stay meaningfully cooler than the air temperature suggests. Two smaller loads beat one crammed one.

Do you have to wash in hot water first?

No. For lice specifically, the dryer alone is enough. Washing is about dirt, and the 130°F hot water cycle in the standard guidance is doing the same thing the dryer does, just wetly.

This matters for items you would rather not put through a hot wash. Hats that lose their shape, a jacket, a stuffed rabbit that has already been through too much: run them dry on high for 20 to 30 minutes and skip the water entirely.

If you are washing anyway, hot water is fine on most cottons and linens. Just be aware that very hot water sets protein-based stains, so check for anything like that first. Our notes on getting grass stains out of white socks cover why heat and certain stains do not mix.

Which items really need to go in the dryer?

Only what touched the affected person’s head in the 48 hours before treatment. That is the honest answer, and it saves most families a full weekend of laundry.

A louse that falls off a scalp typically dies within one to two days because it cannot feed. Eggs knocked loose onto a pillow are very unlikely to hatch off a head, and any that did would need to find a scalp within hours. Fabric that has been sitting untouched for a week is not a threat.

So the realistic list looks like this: pillowcases, sheets, the towel used after the treatment, hats and hoods, hair ties and headbands, the car seat headrest cover if it comes off, and the one stuffed animal that sleeps against the child’s face. Not the entire closet. Not the couch cushions.

Backpacks are on the list only if the kid rests their head on it or stuffs a hat inside, which is more common than parents assume with the oversized packs. If you are already thinking about school gear this month, our guide to picking the right backpack size for a kindergartner covers how those packs get used in practice.

What about things that can’t go in a dryer?

Seal them in a plastic bag for two weeks and set them aside. Two weeks covers the full life cycle, including any egg that might hatch, and the hatchling has nothing to feed on. There is no shortcut that is faster and equally certain.

Dry cleaning also works if the item was headed there anyway. Combs and brushes can be soaked in water heated to about 130°F for five to ten minutes, which is roughly the hottest a home tap runs.

Vacuum the floor and any furniture where the person sat or lay. That is the entire required treatment for upholstery. The CDC specifically advises against fumigant sprays for lice, because they are not necessary and they put pesticide into the air of your home for no return.

Car seats and strollers fall into the vacuum category too, with a quick wipe of hard surfaces. The same practical logic applies to gear that traps odor rather than pests, which we walk through in how to get the smell out of a lunch box.

Can heat kill lice on the head itself?

Professional hot-air devices used in lice clinics do kill eggs on the scalp, but a household hair dryer is not a reliable substitute and can be genuinely unsafe. Several over-the-counter lice treatments contain flammable ingredients, and the CDC warns against using a hair dryer on hair treated with them.

The scalp part of this is a treatment-and-combing job, not a heat job. A fine-tooth nit comb used carefully on wet, conditioned hair, repeated every few days, does more than any appliance you own.

It also helps to know what lice are not. They do not jump, they do not fly, and they do not come from pets, so nothing about the family dog needs treating here. If you are dealing with a separate animal problem, that is its own project, and we looked at one popular home remedy in whether Dawn dish soap really kills fleas on dogs.

Frequently asked questions

Will a dryer kill lice without washing the items first?

Yes. Heat is what kills lice and eggs, so a dry-only cycle on the highest setting for 20 to 30 minutes is enough. This is the better option for hats, jackets, and plush toys that you would rather not put through a hot wash.

What if my dryer only has low or medium heat?

Low and delicate settings may not reach the roughly 130°F needed, so run the longest, hottest cycle available and extend the time to 40 minutes or more. If you are not confident in the setting, bagging the items for two weeks is the certain alternative. A laundromat dryer on high is another easy fallback.

How long can lice survive on a pillow or a couch?

Usually one to two days, because a louse cannot feed away from a scalp. Eggs that fall off are very unlikely to hatch without the warmth of a head, and any that do hatch cannot survive without feeding within hours. That is why the laundry list only covers items used in the 48 hours before treatment.

Do I need to wash every piece of clothing and bedding in the house?

No, and doing so is a common overreaction that costs a full day for no benefit. Wash or dry only what touched the affected person’s head in the past two days, then vacuum floors and furniture. Untouched clothing in a closet or drawer needs nothing.

Does a dryer sanitize cycle work better for lice?

It works, but it is more than the situation requires. Sanitize cycles hold a higher temperature for a set period, which is harder on elastic and printed fabric. A regular high heat cycle already clears the threshold that kills lice and eggs.

The short version is that this problem is smaller than the laundry it seems to demand. Twenty minutes on high heat handles the pillowcases and the hat, two weeks in a sealed bag handles the rest, and a vacuum handles the couch. Everything else is a scalp job with a comb and patience.

If you are stocking up on school gear over the next few weeks anyway, the current deals are worth a scan for hair tools and bedding while back-to-school pricing is still running.