Does Windex Kill Spiders? 7 Key Tips

Spiders such as Black Widows and Brown Recluse use their venom to paralyze the prey including human, pets, and wild animals. Previously, we’ve discussed how you can repel or kill these arachnids using sprays, repellents, and spider bug bombs. Does Windex Kill Spiders

Windex is a common and readily available household cleaner and stain remover. So, a spider has just appeared in your sitting or bedroom and you’re wondering, does Windex kill spiders? 

The direct answer is, YES, Windex will kill spiders since it contains ammonia (in water – ammonium hydroxide) and sodium dodecylbenzene sulfonate that’ll block the spider’s book lungs (breathing holes in spiders) and thus suffocating it. 

Does Windex Kill Spiders? 7 Key Tips

The ammonium concentration emits gas that repel spiders (and other insects) from your house or compound. Windex can also kill other insects such as fruit flies, ants and termites.

However, take caution when using it to kill stinging insects such as bumble bees, wasps and beetles because you may get stung before killing happen.

1. Ammonium hydroxide and Sodium dodecylbenzene sulfonate killing Spiders.

  • Killing action/ ingredients in Windex. The chemicals ammonium hydroxide and Sodium dodecylbenzene sulfonate found in Windex work collectively to kill the spider on contact. The Sodium dodecylbenzene sulfonate accumulate and cling on the spiders’ air sacs blocking the path of air into respiratory system while Ammonium hydroxide is absorbed into the spiders’ blood stream.
  • Oxygen is not absorbed into the blood stream in the book lungs (during intake circulation) due to high affinity of ammonia (ability to be absorb by red blood cells instead of oxygen). Therefore, ammonia in the Windex will cause the spider to suffocate to death on inhalation.
  • Moreover, ammonium (ammonia dissolved in water) in the Windex product also act as repellant for spiders and other insects such as fruit flies found in your house or compound. The Compound emits unpleasant gas that keeps off spiders (ensure that you keep off the room when Windex is in action – it may chock you). 

Related: Spider Bite vs Mosquito Bite

Does Windex Kill White Spiders

2. How to Use/Spray Windex for maximum action.

Windex product is manufacture and packed in a liquid form. Its application is through spraying. Therefore, you will be required to follow these steps when using it.

  • Wear the eye protection (goggles) and nose mask (protects the respiratory system) before use. Ammonium component in the Windex cause burning sensation to eyes and irritation of breathing system when inhaled (can even chock you).
  • Identify the spider hideouts (in holes, cracks, in furniture, garage, within rocks, closets or cobwebs) without disturbing them.
  • In case, you are to use Windex within your house/room/enclosure, lock all windows and doors.
  • Then, remove the top protection seal.
  • Focus the Windex nozzle at the spiders’ hideouts before pressing of the trigger to commence spraying.
  • Spray rapidly at the spider infestation and leave the area before the spiders try to revenge/attack or escape.
  • You will also need to spray other places within the room (to saturation) so as to boost the killing power of Windex.
  • Lock the room for 30 to 60 minutes for efficient working of Windex.
  • After the given period, open the windows and doors to allow fresh air to replace the chocking ammonia that may be within the room for 30 minutes.
  • In case you are using Windex in open area (compound or fields), you will need to cover the spiders hideouts with a bucket after spraying so as to prevent them from escaping before dying and also concentrate the killing power of Windex (wind may blow away spay before full action).

NB: Windex best kill spiders in enclosure/indoor. In case your spider infestation takes longer to die, I recommend you change to another spider killer in the market or use traps. 

Wolf Spider

3. How long (time) Does Windex Take to kill Spiders?

Windex kills on contact. It will take 1 to 15 minute (maximum) to kill a single spider once the spray is inhaled. The rate and time for which the Windex kills a spider is determined by the following factors.

  • The concentration of ammonium content in a given Windex can. In case a can has high concentration of ammonia, it will kill spiders instant on contact while a lowly ammonia concentrated can will take a little bit longer to kill spiders. Normally, household Winder contains 0.05 to 0.1 (5% – 10%) concentration ammonia – this may not kill large spiders instantly on contact, but kills baby spiders and eggs perfectly well.
  • The Size of Area Being splayed. Large rooms (more than 200sq feet) need more than one can/bottle to ensure spider infestation is effective and completely killed/eliminated. Ammonia in the Windex spray diffuses rapidly thus, a give room should be saturated well when spraying to avoid incomplete killing of the spider.
  • Type of Area being treated/sprayed. Windex spray kills spiders in an enclosed room faster than in open fields. Closed place/room concentrates the killing power of Windex while open field loses the spray easily with the wind and thus has less killing effect on spiders. Windex spray directed to holes, cracks and closet (spider hideouts) is more effective (takes less time) that one sprayed in the open space within a room or field/compound. 

4. What else Kills/eliminates spiders?

Apart from Windex, you can use the following substances or methods (natural/artificial) to kill or get rid of spiders in your place.

a. Use of Vinegar.

Vinegar is a weak acid of pH between 4 to 8 that emits smell which keep off spiders in your house or compound without necessarily killing them. Your will require to mix 1 cup of vinegar with 5 cups of water. Then, spray the concoction in the spiders’ hideouts to saturation. You will require to spray the mixture twice per day for 10 to 15 days.

You can also blend white vinegar with coconut oil in a 5:1 ratio. The coconut oil will form a thick layer on their body blocking their respiratory system. In addition, the mixture emits unbearable smell that that keep off spiders. You will have to spray this mixture daily for 2 to 6 weeks for complete elimination of spiders in your home. This combination is friendly as it cause no negative effect on user on application.

b. Using Black peppers.

Black peppers are natural way of eliminating spider infestation in your home. It is a perfect solution when you need to repel spiders in your place than kill. You will need to grind several black peppers into fine pieces and sprinkle to spider hideouts.

You can also boil (3 to 4 cups of water) the black peppers and then strain the water before spraying in spider-infested areas. Black pepper is also able to repel other insects such as spider mites and ants.  Keep of kids while spraying your house/place – the spicy peppered liquid cause itching and burning sensation.

c. Use of Diatomaceous Earth.

Diatomaceous Earth is one of the best natural ways of killing and eliminating spiders in your home as it occur as a natural siliceous and soft sedimentary rock that has a killing portion in it. Your will need to grind it into very fine particles before sprinkling on to spider infested areas.

Diatomaceous Earth acts on contact. It has sharp edges that penetrates easily killing the entire life cycle of spiders (eggs, larvae and adult). 

On contact, the Diatomaceous Earth absorbs fat and oil from the exoskeleton (specifically cuticle) of the spiders thus killing them by dehydration.

Moreover, Diatomaceous Earth emits smell that repels spiders and other insects such as cockroaches and fleas in your home. NB: Wear gloves (dehydrates hand), breathing Masks (causes irritation of breathing system) and use food grade diatomaceous Earth for safety measure.

d. Use of Essential Oils.

These are natural spider repellents that help keep away spiders from your house or compound. They produce smell that disrupt the spider infestation sending them off.

Some of these Essential oils for bed bugs include Peppermint oil, pine oil, sweet orange oil, garlic oil, rose oil, cedar wood oil and citronella oil among others. You will only need to spray/apply essential oil in spider hideouts or infested area after every 3 days for a month. Essential oils also repel flies, lizards and mosquitoes in your home.

5. Which other insects can Windex kill/eliminate?

Apart from eliminating spiders, Windex can kill other insects such as bumblebees, wasps, ants, spider mites, beetle, moths and houseflies. You will only require to spray a colony of these insects, their path and hideouts and you will find them death seconds.

Windex is quick acting for normal household concentration product when killing these insects as they are smaller and need less killing dose than spiders (you won’t need to order for special concentration package).

Windex will kill these insects by blocking the respiratory system (spiracles) thus suffocating. The cause of suffocation is due insufficient supply/circulation of oxygen in the body, as ammonia remain held in red blood cells within heamocoel (open blood cavity in insects).

Moreover, Windex will repel these insects since ammonium component in the product produce odor that disturb their presence.

Is Windex Poisonous to Humans and Pets When Used To Kill Spiders?

The Windex is not 100% for human use as it contains ingredients that affect both your humans and pets during use. Ammonium hydroxide may cause irritation of skin and respiratory system when inhaled. In addition, it cause watery eyes and burning sensation to your humans and pets on contact.

The fragrance and Liquitint sky blue dye used in Windex may cause respiratory disturbance and are high source of allergy for allergic sensitive people. These fragrances make your pets cough abnormally and even get chocked.

Chemicals Hexoxyethanol, Isopropanolamine and Sodium dodecylbenzene sulfonate cause skin irritation and burn on long use. They also have respiratory disturbance when inhaled.

NB: It is very important to wear eye protection, hand gloves and breathing mask when praying Windex.


Windex will kill spider infestation in your house or compound on contact. It contains ammonium compound, which inhibit absorption of oxygen in the book lungs of spiders thus killing them by suffocation.

Sodium dodecylbenzene sulfonate in Windex blocks the air sacs in the chitin making air impassable during respiratory process. Windex also repel spiders and other insects such as bumblebees, wasps, ants, spider mites, beetle, moths and houseflies.

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