by David Moore
Manager of Technical Services and Board Certified Entomologist
By reducing the amount and/or changing the color of outside light, you can drastically reduce the attraction of insects and other pests to home. One of the three most common long-distance attractants to insects is lighting. Night flying insects navigate by moon and star light, so out exterior lighting tricks them. These insects navigate by keeping themselves aligned at a certain angle relative to a light source.
Artificial light interferes with an insect’s ability to detect moonlight. Your exterior lighting is brighter to them, and radiates light on all sides. Since your lighting emits light in multiple directions, the insect simply cannot keep the light source at a constant angle, as it does with the moon.
Besides insects, many other pests will visit your home to feast on the abundance of insects. Frogs, spiders, and bats are just a few potential pests that can set up shop at your home. They can have an impact on the number of pests in your area, but many people do not want them to impact their home either.
After sunset, go outside and slowly walk around your house looking for where lights are positioned, the color of light they produce, and for any light escaping from inside your house to the outside. To ensure that your home isn’t a magnet to insects, here are some light management tips you can implement around your home to make your home less of a night-time attraction.
Any kind of white light (including fluorescent or incandescent, mercury vapor, halogen, and LED) should not be used within 50 feet of a home. The best kind of lights to use on the home’s exterior near entryways is yellow fluorescent or yellow LED lights. The best place to mount such lights is on the hinged side of the door so that its light will shine minimally to the inside of your home when the door is opened. If you need to light large exterior areas for security reasons, use high-pressure sodium lights, which are the least attractive to insects. This includes lighting the yard/grounds around your home which is best done by mounting high-pressure sodium vapor lights on stand-alone poles. Many people with basement garage entrances mount this light high up on the gable.
Many people choose to use mercury vapor lights because they are less expensive to buy than sodium vapor lights. However, while sodium vapor lights do cost more per light, they are actually cheaper to run. So, you will reach a break-even point on the cost.
Keep white light from escaping from the inside of your home, since all white light attracts insects. Inspect each outside door including any garage doors, and add or repair weather seals or install door brushes to stop the light from leaking out. Take a look at all your windows and add or repair weather seals to stop light from escaping out.
Escaping white light is like a searchlight to insects. Any area where there is an opening to the outside, whether it is screened or not, should have the escaping light changed to less attractive LED (LED lights do not emit attractive UV light), so this will reduce the number of night-flying insects seeking/attempting to come inside. By tinting the windows on doors, much less light shines through the door so it isn’t as attractive to insects, but you can still see the people inside or activity outside.
It should be noted that screens whose mesh is small enough to keep out most insects are so tightly woven as to interfere with seeing out and will impede air flow (= unacceptable). However, since regular window screens will keep out the larger flying insects, they are valuable tools. So, all windows should be properly screened if they can be opened.
Performing an exterior night-time light inspection of your home can reveal many things about your home. This inspection can tell you why your home is attractive to night-flying insects, how to decrease its attractiveness, how to reduce the number of these insects that manage to find a way to enter your home, and how they are getting into your home.