Friday, October 4, 2013

Gold Star Home Inspections, LLC

Three Deadly Mistakes Every Home Buyer Should Avoid

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Deadly Mistake #1: Thinking you can't afford it.
 
Many people who thought that buying the home they wanted was simply out of their reach are now enjoying a new lifestyle in their very own homes. 
 
Buying a home is the smartest financial decision you will ever make.  In fact, most homeowners would be broke at retirement if it wasn't for one saving grace -- the equity in their homes.  Furthermore, tax allowances favor home ownership. 
Real estate values have always risen steadily.  Of course, there are peaks and valleys, but the long-term trend is a consistent increase.  This means that every month when you make a mortgage payment, the amount that you owe on the home goes down and the value typically increases.  This "owe less, worth more" situation is called equity build-up and is the reason you can't afford not to buy.
 
Even if you have little money for a down payment or credit problems, chances are that you can still buy that new home.  It just comes down to knowing the right strategies, and working with the right people.  See below.
  
  
Deadly Mistake #2: Not hiring a buyer's agent to represent you.
 
Buying property is a complex and stressful task.  In fact, it is often the biggest, single investment you will make in your lifetime.  At the same time, real estate transactions have become increasingly complicated.  New technology, laws, procedures, and competition from other buyers require buyer agents to perform at an ever-increasing level of competence and professionalism.  In addition, making the wrong decisions can end up costing you thousands of dollars.  It doesn't have to be this way!
 
Work with a buyer's agent who has a keen understanding of the real estate business and the local market.  A buyer's agent has a fiduciary duty to you.  That means that he or she is loyal only to you and is obligated to look out for your best interests.  A buyer's agent can help you find the best home, the best lender, and the best home inspector in your area.  That inspector should be an InterNACHI-certified home inspector because InterNACHI inspectors are the most qualified and  best-trained inspectors in the world.
Trying to buy a home without an agent or a qualified inspector is, well... unthinkable.
 
 
Deadly Mistake #3: Getting a cheap inspection.
 
Buying a home is probably the most expensive purchase you will ever make.  This is no time to shop for a cheap inspection.  The cost of a home inspection is small relative to the value of the home being inspected.  The additional cost of hiring a certified inspector is almost insignificant by comparison.  As a home buyer, you have recently been crunching the numbers, negotiating offers, adding up closing costs, shopping for mortgages, and trying to get the best deals.  Don't stop now!  Don't let your real estate agent, a "patty-cake" inspector, or anyone else talk you into skimping here.  
  
InterNACHI front-ends its membership requirements.  InterNACHI turns down more than half the inspectors who want to join because they can't fulfill the membership requirements. 
 
InterNACHI-certified inspectors perform the best inspections, by far.  InterNACHI-certified inspectors earn their fees many times over.  They do more, they deserve more and -- yes -- they generally charge a little more.  Do yourself a favor...and pay a little more for the quality inspection you deserve.

Gold Star Home Inspections, LLC

Green Lumber

"Green lumber" is another term for wet lumber, which is wood used in construction that has a moisture content of more than 19%.
Moisture Content
InterNACHI finds that green lumber is more commonly used in arid regions of the United States, such as Arizona and parts of California, because the wood will dry more quickly. Damper regions often require kiln-dried wood, which must have a moisture content of 19% or less. The additional expense of kiln-dried wood is the reason it is used in only a small portion of construction.
Freshly cut wood will gradually lose moisture until it reaches equilibrium with its surroundings, which is referred to as its “equilibrium moisture content” (EMC). As it Mold on geren lumber dries, the wood will shrink in size. Wood will continue to lose moisture until it reaches EMC, at which point it’s said to have reached its “in-service condition.”
The water that fills wood cells is known as “free water,” which accounts for most of the water weight of a tree. Cell walls also contain water, which is known as “bound water.” The weight of the water can account for more than half the mass of a tree in some species when it is cut down. Ideally, the lapse between the time the tree is first cut until the tree’s wood is used in construction will allow for most or all of the free water to evaporate, but this does not always happen. Shortly after wood is processed in mills, it is bundled and wrapped in plastic, which retards evaporation. The wood has little chance to dry until the bundle is unwrapped and the framing process begins at the construction site.
Why is green lumber used?
  • It is relatively inexpensive.
  • Green lumber is softer than seasoned wood. It can be cut more easily, is not as likely to split, and nails can be driven into it more easily.  
Problems associated with the use of green lumber:Nail pop
  • nail pops. Where wood frame members shrink, a gap is created between the nail and the drywall. If the drywall and nail are pushed together, the nail may force the drywall surface to elevate. A common place for nail pops to occur is at the base of vaulted ceilings near external walls. Although unsightly, they usually do not affect the building’s structural integrity. Homeowners who wish to fix this problem can simply push the nail further into the wall;
  • mold. Mold can begin to grow on green lumber before it is even used in construction. Airborne mold spores are found almost everywhere, and they can easily cause mold growth on wet wood surfaces, especially while it is being transported long distances by train;
  • difficult to paint or stain. Low-permeability paint can prevent water vapor from exiting the wood, resulting in bubbling of the painted surface;
  • sap.  Sap and other liquid substances within the wood's interior can ooze out and cause discoloration.
  • gaps in exterior trim can be created during shrinkage. This is especially true at the fascia. 
In summary, a number of problems can result from the use of green lumber.

From Green Lumber - Int'l Association of Certified Home Inspectors (InterNACHI) http://www.nachi.org/green-lumber.htm#ixzz2gmTPLGLJ

Gold Star Home Inspections, LLC

Factory-Built Fireplaces

There’s nothing like coming home and warming up next to a roaring fire during the long, cold months of winter, or even chilly evenings in any season.  Long commutes to work in the cold and the increasingly short hours of daylight in the fall and winter are made more bearable by the comfort and familiarity of family gatherings by the fire.  It may be for this reason that some type of wood-burning enclosure has remained a staple of many households, even though open fire is no longer a necessity for cooking and heating.  With this in mind, let's take a look at one of the more modern options available, the factory-built fireplace.
What is a factory-built fireplace and how does it differ from a masonry fireplace?
The traditional masonry fireplace is based largely on the innovations of Count Rumford, an18th-century inventor.  His applied theories on thermodynamics led to the design of a restricted chimney opening to increase updraft, which allowed fire to burn in an enclosure without smoke filling the room.  Rumford’s design quickly achieved wide popularity in London households, and he became something of a celebrity as news of his innovation spread. 
Factory-built fireplaces now make up approximately 75% of all types of fireplaces. Unlike traditional masonry fireplaces, which are built on site, factory-built fireplaces are designed to allow for installation at a later date, although they are just as often used for new construction. 
A factory-built fireplace is made up of a firebox enclosed within a steel cabinet, and a steel chimney or flue.  It is lightweight, inexpensive, safe and efficient, and can be installed fairly easily on any floor of a home.  Pre-manufactured masonry fireplaces are also available, and they incorporate engineering techniques not often used in field-constructed fireplaces, such as a listed venting system.
Zero Clearance
Factory-built fireplaces are also often called “zero-clearance” fireplaces because of their minuscule safe-clearance requirements.  An insulating air blanket is incorporated in the design to keep the outer wall of the fireplace cool, which allows safe installation in very close proximity to wood framing.  In general, ½-inch of clearance to combustibles is required around the outside of the firebox enclosure, and 2 inches of clearance are required around the chimney, except where the firestop is installed if a chimney passes through two levels of a house.  Different manufacturers may have different suggested clearances, and it is important for installers to note this for proper and safe installation. 
Safety and Maintenance
Factory-built fireplaces pass rigorous testing standards established by the  Underwriters Laboratories and the American Gas Association.  Properly installed, factory-built fireplaces have an excellent safety record.  However, as in any situation where an open flame is involved, there are some things to keep in mind in order to avoid any risk of fire hazard. 
If the fireplace is installed on top of any combustible material, such as carpet or wood, it must rest on a metal or tile panel that extends the length and width of the appliance.
Any combustible flooring near the fuel opening must be insulated with non-combustible floor protection.
Room air-inlet and outlet grilles must be unobstructed.
The same fire-safety precautions that are used for a traditional fireplace should be observed when a factory-built fireplace is in use.
In order to ensure safe and optimal operation, normal maintenance and cleaning are required, similar to those used for a traditional fireplace.  The chimney should be inspected monthly during the heating season to determine if creosote (the black, oily accretion that builds up as a result of incomplete burning of wood) has accumulated.  A professional chimney sweep should be hired to clean out the unit at least once a year. 

 Gold Star Home Inspections, LLC

Electrical Safety

www.goldstarinspection.com

Electricity is an essential part of our lives. However, it has the potential to cause great harm. Electrical systems will function almost indefinitely, if properly installed and not overloaded or physically abused. Electrical fires in our homes claim the lives of 485 Americans each year and injure 2,305 more. Some of these fires are caused by electrical system failures and appliance defects, but many more are caused by the misuse and poor maintenance of electrical appliances, incorrectly installed wiring, and overloaded circuits and extension cords.  Some safety tips to remember:
  • Never use anything but the proper fuse to protect a circuit.
  • Find and correct overloaded circuits. 
  • Never place extension cords under rugs. 
  • Outlets near water should be GFCI-type outlets. 
  • Don't allow trees near power lines to be climbed. 
  • Keep ladders, kites, equipment and anything else away from overhead power lines. 
Electrical Panels
Electricity enters the home through a control panel and a main switch where one can shut off all the power in an emergency. These panels are usually located in the basement. Control panels use either fuses or circuit breakers. Install the correct fuses for the panel. Never use a higher-numbered fuse or a metallic item, such as a penny. If fuses are used and there is a stoppage in power, look for the broken metal strip in the top of a blown fuse. Replace the fuse with a new one marked with the correct amperage. Reset circuit breakers from "off" to "on." Be sure to investigate why the fuse or circuit blew. Possible causes include frayed wires, overloaded outlets, or defective appliances. Never overload a circuit with high-wattage appliances. Check the wattage on appliance labels. If there is frayed insulation or a broken wire, a dangerous short circuit may result and cause a fire. If power stoppages continue or if a frayed or broken wire is found, contact an electrician.
Outlets and Extension Cords

Make sure all electrical receptacles or outlets are three-hole, grounded outlets. If there is water in the area, there should be a GFCI or ground-fault circuit interrupter outlet. All outdoor outlets should be GFCIs. There should be ample electrical capacity to run equipment without tripping circuit breakers or blowing fuses. Minimize extension cord use. Never place them under rugs. Use extension cords sparingly and check them periodically. Use the proper electrical cord for the job, and put safety plugs in unused outlets.

Electrical Appliances

Appliances need to be treated with respect and care. They need room to breathe. Avoid enclosing them in a cabinet without proper openings, and do not store papers around them. Level appliances so they do not tip. Washers and dryers should be checked often. Their movement can put undue stress on electrical connections. If any appliance or device gives off a tingling shock, turn it off, unplug it, and have a qualified person correct the problem. Shocks can be fatal. Never insert metal objects into appliances without unplugging them. Check appliances periodically to spot worn or cracked insulation, loose terminals, corroded wires, defective parts and any other components that might not work correctly. Replace these appliances or have them repaired by a person qualified to do so.
Electrical Heating Equipment

Portable electrical heating equipment may be used in the home as a supplement to the home heating system. Caution must be taken when using these heating supplements. Keep them away from combustibles, and make sure they cannot be tipped over. Keep electrical heating equipment in good working condition. Do not use them in bathrooms because of the risk of contact with water and electrocution. Many people use electric blankets in their homes. They will work well if they are kept in good condition. Look for cracks and breaks in the wiring, plugs and connectors. Look for charred spots on both sides. Many things can cause electric blankets to overheat. They include other bedding placed on top of them, pets sleeping on top of them, and putting things on top of the blanket when it is in use. Folding the blankets can also bend the coils and cause overheating.
Children

Electricity is important to the workings of the home, but can be dangerous, especially to children. Electrical safety needs to be taught to children early on. Safety plugs should be inserted in unused outlets when toddlers are in the home. Make sure all outlets in the home have face plates. Teach children not to put things into electrical outlets and not to chew on electrical cords. Keep electrical wiring boxes locked. Do not allow children to come in contact with power lines outside. Never allow them to climb trees near power lines, utility poles or high tension towers.
Electricity and Water

A body can act like a lightning rod and carry the current to the ground. People are good conductors of electricity, particularly when standing in water or on a damp floor. Never use any electrical appliance in the tub or shower. Never touch an electric cord or appliance with wet hands. Do not use electrical appliances in damp areas or while standing on damp floors. In areas where water is present, use outlets with GFCIs. Shocks can be fatal.
Animal Hazards

Mice and other rodents can chew on electrical wires and damage them. If rodents are suspected or known to be in the home, be aware of the damage they may cause, and take measures to get rid of them.
Outside Hazards

There are several electrical hazards outside the home. Be aware of overhead and underground power lines. People have been electrocuted when an object they are moving has come in contact with the overhead power lines. Keep ladders, antennae, kites and poles away from power lines leading to the house and other buildings. Do not plant trees, shrubs or bushes under power lines or near underground power lines. Never build a swimming pool or other structure under the power line leading to your house. Before digging, learn the location of underground power lines.

Do not climb power poles or transmission towers. Never let anyone shoot or throw stones at insulators. If you have an animal trapped in a tree or on the roof near electric lines, phone your utility company. Do not take a chance of electrocuting yourself. Be aware of weather conditions when installing and working with electrical appliances. Never use electrical power tools or appliances with rain overhead or water underfoot. Use only outdoor lights, fixtures and extension cords. Plug into outlets with a GFCI. Downed power lines are extremely dangerous. If you see a downed power line, call the electric company, and warn others to stay away. If a power line hits your car while you are in it, stay inside unless the car catches fire. If the car catches fire, jump clear without touching metal and the ground at the same time.
MORE SAFETY PRECAUTIONS :
  • Routinely check your electrical appliances and wiring.
  • Hire an InterNACHI inspector. InterNACHI inspectors must pass rigorous safety training and are knowledgeable in the ways to reduce the likelihood of electrocution.
  • Frayed wires can cause fires. Replace all worn, old and damaged appliance cords immediately.
  • Use electrical extension cords wisely and don't overload them.
  • Keep electrical appliances away from wet floors and counters; pay special care to electrical appliances in the bathroom and kitchen.
  • Don't allow children to play with or around electrical appliances, such as space heaters, irons and hair dryers.
  • Keep clothes, curtains and other potentially combustible items at least 3 feet from all heaters.
  • If an appliance has a three-prong plug, use it only in a three-slot outlet. Never force it to fit into a two-slot outlet or extension cord.
  • Never overload extension cords or wall sockets. Immediately shut off, then professionally replace, light switches that are hot to the touch, as well as lights that flicker. Use safety closures to childproof electrical outlets.
  • Check your electrical tools regularly for signs of wear. If the cords are frayed or cracked, replace them. Replace any tool if it causes even small electrical shocks, overheats, shorts out or gives off smoke or sparks.
In summary, household electrocution can be prevented by following the tips offered in this guide and by hiring an InterNACHI inspector

From Electrical Safety - Int'l Association of Certified Home Inspectors (InterNACHI) http://www.nachi.org/electric.htm#ixzz2gmSXXgOm

 Gold Star Home Inspections, LLC

Dryer Vent Safety

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Clothes dryers evaporate the water from wet clothing by blowing hot air past them while they tumble inside a spinning drum. Heat is provided by an electrical heating element or gas burner. Some heavy garment loads can contain more than a gallon of water which, during the drying process, will become airborne water vapor and leave the dryer and home through an exhaust duct (more commonly known as a dryer vent).
A vent that exhausts moist air to the home's exterior has a number of requirements:
  1. It should be connected. The connection is usually behind the dryer but may be beneath it. Look carefully to make sure it’s actually connected.
  2. It should not be restricted. Dryer vents are often made from flexible plastic or metal duct, which may be easily kinked or crushed where they exit the dryer and enter the wall or floor. This is often a problem since dryers tend to be tucked away into small areas with little room to work. Vent hardware is available which is designed to turn 90° in a limited space without restricting the flow of exhaust air. Restrictions should be noted in the inspector's report. Airflow restrictions are a potential fire hazard.
  3. One of the reasons that restrictions are a potential fire hazard is that, along with water vapor evaporated out of wet clothes, the exhaust stream carries lint – highly flammable particles of clothing made of cotton and polyester. Lint can accumulate in an exhaust duct, reducing the dryer’s ability to expel heated water vapor, which then accumulates as heat energy within the machine. As the dryer overheats, mechanical failures can trigger sparks, which can cause lint trapped in the dryer vent to burst into flames. This condition can cause the whole house to burst into flames. Fires generally originate within the dryer but spread by escaping through the ventilation duct, incinerating trapped lint, and following its path into the building wall.
InterNACHI believes that house fires caused by dryers are far more common than are generally believed, a fact that can be appreciated upon reviewing statistics from the National Fire Protection Agency. Fires caused by dryers in 2005 were responsible for approximately 13,775 house fires, 418 injuries, 15 deaths, and $196 million in property damage. Most of these incidents occur in residences and are the result of improper lint cleanup and maintenance. Fortunately, these fires are very easy to prevent.

The recommendations outlined below reflect International Residential Code (IRC) SECTION M1502 CLOTHES DRYER EXHAUST guidelines:
M1502.5 Duct construction.
Exhaust ducts shall be constructed of minimum 0.016-inch-thick (0.4 mm) rigid metal ducts, having smooth interior surfaces, with joints running in the direction of air flow. Exhaust ducts shall not be connected with sheet-metal screws or fastening means which extend into the duct.
This means that the flexible, ribbed vents used in the past should no longer be used. They should be noted as a potential fire hazard if observed during an inspection.
M1502.6 Duct length.
The maximum length of a clothes dryer exhaust duct shall not exceed 25 feet (7,620 mm) from the dryer location to the wall or roof termination. The maximum length of the duct shall be reduced 2.5 feet (762 mm) for each 45-degree (0.8 rad) bend, and 5 feet (1,524 mm) for each 90-degree (1.6 rad) bend. The maximum length of the exhaust duct does not include the transition duct.
This means that vents should also be as straight as possible and cannot be longer than 25 feet. Any 90-degree turns in the vent reduce this 25-foot number by 5 feet, since these turns restrict airflow.

A couple of exceptions exist:
  1. The IRC will defer to the manufacturer’s instruction, so if the manufacturer’s recommendation permits a longer exhaust vent, that’s acceptable. An inspector probably won’t have the manufacturer’s recommendations, and even if they do, confirming compliance with them exceeds the scope of a General Home Inspection.
  2. The IRC will allow large radius bends to be installed to reduce restrictions at turns, but confirming compliance requires performing engineering calculation in accordance with the ASHRAE Fundamentals Handbook, which definitely lies beyond the scope of a General Home Inspection.
M1502.2 Duct termination.
Exhaust ducts shall terminate on the outside of the building or shall be in accordance with the dryer manufacturer’s installation instructions. Exhaust ducts shall terminate not less than 3 feet (914 mm) in any direction from openings into buildings. Exhaust duct terminations shall be equipped with a backdraft damper. Screens shall not be installed at the duct termination.
Inspectors will see many dryer vents terminate in crawlspaces or attics where they deposit moisture, which can encourage the growth of mold, wood decay, or other material problems. Sometimes they will terminate just beneath attic ventilators. This is a defective installation. They must terminate at the exterior and away from a door or window. Also, screens may be present at the duct termination and can accumulate lint and should be noted as improper. 
M1502.3 Duct size.
The diameter of the exhaust duct shall be as required by the clothes dryer’s listing and the manufacturer’s installation instructions.
Look for the exhaust duct size on the data plate.
M1502.4 Transition ducts.
Transition ducts shall not be concealed within construction. Flexible transition ducts used to connect the dryer to the exhaust duct system shall be limited to single lengths not to exceed 8 feet (2438 mm), and shall be listed and labeled in accordance with UL 2158A.
In general, an inspector will not know specific manufacturer’s recommendations or local applicable codes and will not be able to confirm the dryer vent's compliance to them, but will be able to point out issues that may need to be corrected.

Gold Star Home Inspections, LLC

Crawlspace Hazards and Inspection

by Ken Woolbright 
Crawlspace
Crawlspaces are host to a large number of conditions that may harm the house or inspectors. Never enter a crawlspace without proper personal protective equipment.
Crawlspaces are notorious for the nasty discoveries made there by inspectors, and it isn’t hard to figure out why; for one thing, their cool, dark environment attracts undesirable pests and can promote dangerous conditions. And since crawlspaces are mostly unmonitored, hazards can breed there unchecked for long periods of time. The following are some of the more common dangers discovered in crawlspaces:
  • mold and fungus. Just like pests, mold and fungus can grow rapidly in crawlspaces. They are both a health concern as well as a cause of wood decay, which can require a costly repair. Airborne mold spores can potentially enter the living space from the crawlspace. Molds produce allergens (substances that can cause allergic reactions), irritants and, in some cases, potentially toxic substances called mycotoxins. Inhaling or touching mold or mold spores may cause allergic reactions in sensitive individuals. Allergic responses include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin rash (dermatitis). Homes infected with molds and fungus are also much more difficult to sell, often requiring costly remediation prior to closing the deal.
  • pests. Dirt crawlspaces provide the environment that is enjoyed by ants, termites, and various other pests. Termites cannot survive long outside of their mud tubes, which you may see on foundation walls and piers. Carpenter ants should be plainly obvious as well, and both of theses pests can cause structural damage. Also bear in mind that where there are pests, there may also be pesticides, perhaps improperly applied, which is one reason why you should not enter crawlspaces without personal protective equipment. Snakes, spiders, bees and scorpions may also be lingering in the crawlspace, and while they pose little structural danger to the house, they certainly can harm you! Rapid retreat there can be difficult, so be cognizant of escape paths.
  • hantavirus. Crawlspaces are perhaps the most likely sites in houses where hantavirus may be found. This is partly due to the fact that rodents that carry the pathogen are attracted to areas that are undisturbed by humans. Also, crawlspaces are generally dark places that lack ultraviolet (UV) radiation, which can rapidly inactivate the virus. Exposure to hantavirus may lead to Hantavirus Cardiopulmonary Syndrome (HCS), characterized by headaches, fever, difficulty breathing and, often, death. There is no known cure, vaccine or treatment that specifically targets HCS. However, if the symptoms are recognized early, patients may benefit from oxygen therapy.
  • asbestos insulation. Do not disturb asbestos! The microscopic fibers that cause illness become airborne when the insulation is handled or disturbed, and if it appears to be in good shape, it might not be a problem at all. Prolonged exposure to asbestos insulation can cause mesothelioma, which is a cancer of the lining of the chest and the abdominal cavity, as well as asbestosis, in which the lungs become scarred with fibrous tissue.
  • standing water or sewage.  Dirt crawlspaces are susceptible to water seepage, which can create a host of problems, such as microbial growth, odors, damage to stored belongings, and risk of electrical shock.
  • structural collapse. If the home itself is unstable, it might be dangerous to enter its crawlspace. It is easy to become pinned, trapped or even crushed by unstable crawlspaces. Make sure someone knows that you are inspecting the crawlspace before you enter it.
  • improper wiring. Watch for loose wiring, open junction boxes, or wiring that has become loose and fallen to the floor. 
  • source of energy waste. Traditionally, crawlspaces have been vented to prevent problems with moisture, and most building codes require vents to aid in removing moisture from the crawlspace. However, many building professionals now recognize that ventilated crawlspaces allow a great deal of heat loss in the winter and moisture intrusion in the summer from moist air.
In summary, inspectors should expect to encounter a number of dangerous conditions in crawlspaces, so they should take proper precautions before entering them.

Gold Star Home Inspections, LLC  

Bug Zappers

by Ken Woolbright
www.goldstarinspection.com
A bug zapper is a popular exterior appliance installed by a homeowner or food handler to attempt localized control of flying insect populations. Its name comes from the characteristic "zap" sound produced when an insect is electrocuted. Around homes, they are primarily used to kill biting (female) mosquitoes, which create itchy bumps and can transmit the West Nile Virus or encephalitis, malaria and yellow fever. While Popular Mechanics produced a sketch of a bug zapper as early as 1911, it wasn't until 1934 that parasitology professor Dr. W.B. Herms introduced the electronic insect killer that became the model for all future bug zappers.
How They Work

 Bug zappers typically consist of the following components:
  • the housing, which is a plastic or grounded metal exterior casing that contains the zapper’s parts. It may be shaped liked a lantern, a cylinder or a rectangular cube. A grid design may be incorporated to prevent children and animals from touching the electrified grids inside the device;
  • a light source, which is usually fluorescent-type, such as mercury, neon or ultraviolet light;
  • wire grids or screens, which are electrified layers of wire mesh that surround the light source. These grids are separated by a tiny gap roughly the size of a typical insect (several millimeters); and
  • the transformer, which is the device that electrifies the wire mesh, changing the 120-volt, electrical-line voltage to 2,000 volts or more. 
Bug zappers work by luring flying insects with fluorescent (typically ultraviolet) light into a deadly electrical current. Because the flower patterns that attract insects are better revealed in ultraviolet light, many flying insects that feed on flowers will be drawn to the bug zapper. Before they reach the light, however, they will come into contact with the wire mesh, completing the electrical circuit and disintegrating.
Bug zappers can kill many thousands of flying insects nightly. Some models incorporate a tray designed to collect scattered insect parts, although many models allow the debris to fall to the ground below.
Effective or Not?
Despite their widespread use, numerous studies have called into question the effectiveness and safety of bug zappers. Two of the more pressing issues are the following:
  • Female (biting) mosquitoes and other biting insects are more attracted to the carbon dioxide (CO2) and water vapor in the breath of animals than to ultraviolet light. As a consequence, standard bug zappers typically kill large numbers of harmless and beneficial insects, such as beetles and fireflies, and ultimately fail to reduce the number of the types of insects that prompt the purchase of a bug zapper in the first place. In fact, one study found that just 0.22% of the insects killed by bug zappers were biting insects, while nearly half of those killed were harmless, non-biting aquatic insects from nearby rivers and streams. The study even found “the probability of being bitten by mosquitoes increases in the vicinity of these traps,” perhaps because the biting insects are actually lured by the ultraviolet light but become distracted by the far more attractive human prey nearby. Some newer bug zappers address this issue by incorporating a CO2 container at the bottom of the lamp. Other designs attract mosquitoes into a netting device on the outside of the bug zapper that traps the mosquito, and eventually the insect dies of dehydration.
  • The electrocuted insects are blasted into a fine mist that contains insect parts as well as unkilled bacteria and viruses up to 7 feet (2.1 m) from the device. The air surrounding the zapper may become contaminated with campylobacter jejuni, staphylococci, serratia marcescens, enterococci, and other potentially dangerous organisms commonly carried by flies. For this reason, a bug zapper should never be placed over a food preparation area or in a hospital or any other sterile environment to prevent the potential spread of disease. Children should not be allowed to play beneath an operating bug zapper. Models that contain a tray to catch insect debris are less of a health risk.
Tips for Homeowners
Bug zappers do not present more of a fire hazard than other electrical devices. Most units have been UL-tested, but, as with any outdoor electrical appliance, care must be taken to ensure that electrical cords do not become frayed or wet.  They should also be connected to GFCI-protected receptacles. 
Inspectors may pass on the following mosquito-control techniques to concerned homeowners:
  • Do not allow water to accumulate anywhere in your yard for more than a few days. Eliminate sources of standing water, especially old tires, flower pots, clogged gutters, tin cans or buckets. Fill in or drain ruts, puddles and other low places in the yard. Even holes in trees from rot and hollow stumps can collect water that can harbor mosquitoes. Cover trash containers to keep rainwater out, and drill holes in the bottom of trash containers to allow any water to drain. Repair leaky pipes and outdoor faucets.
  • Bug zappers should be cleaned out at least annually to prevent the accumulation of bug parts on the wire mesh, which will decrease the effectiveness of the unit, and may lead to illness if the bug parts contaminate foods, drink or items used by people or pets.
  • Keep grass cut short and any shrubbery well-trimmed, as adult mosquitoes use these places to rest and hide.
  • Encourage the presence of bats by installing a bat house. These winged mammals pose little danger to humans, and a single brown bat can consume up to 600 mosquitoes per hour.
  • Install a fan. Mosquitoes and other flying insects will avoid moving air.
  • Wear long-sleeve shirts and pants. The pesticide permethrin may be applied to clothing to protect against mosquitoes and ticks. Beware that while permethrin is relatively safe for people and dogs, it is toxic to cats.
In summary, bug zappers are a common yet controversial means of controlling biting insect populations around the home, and caution should be taken in their selection and use.