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Bathroom Ventilation Ducts and Fans

MiHome Property Inspections LLC • Jul 31, 2023

Bathroom ventilation systems are designed to exhaust odors and moist air to the home's exterior. Typical systems consist of a ceiling fan unit connected to a duct that terminates at the roof.

Fan Function

 The fan may be controlled in one of several ways:

  • Most are controlled by a conventional wall switch.
  • A timer switch may be mounted on the wall.
  • A wall-mounted humidistat can be pre-set to turn the fan on and off based on different levels of relative humidity.


Newer fans may be very quiet but work just fine. Older fans may be very noisy or very quiet. If an older fan is quiet, it may not be working well. Inspectors can test for adequate fan airflow with a chemical smoke pencil or a powder puff bottle, but such tests exceed InterNACHI's Standards of Practice. Bathroom ventilation fans should be inspected for dust buildup that can impede air flow. Particles of moisture-laden animal dander and lint are attracted to the fan because of its static charge. Inspectors should comment on dirty fan covers. Ventilation systems should be installed in all bathrooms. This includes bathrooms with windows, since windows will not be opened during the winter in cold climates. 


Defects


The following conditions indicate insufficient bathroom ventilation:

  • moisture stains on walls or ceilings;
  • corrosion of metal;
  • visible mold on walls or ceilings;
  • peeling paint or wallpaper;
  • frost on windows; and
  • high levels of humidity.


The most common defect related to bathroom ventilation systems is improper termination of the duct. Vents must terminate at the home exterior. 


The most common improper terminations locations are:

  • mid-level in the attic. These are easy to spot;
  • beneath the insulation. You need to remember to look. The duct may terminate beneath the insulation or there may be no duct installed; and 
  • under attic vents. The duct must terminate at the home exterior, not just under it.


Improperly terminated ventilation systems may appear to work fine from inside the bathroom, so the inspector may have to look in the attic or on the roof. Sometimes, poorly installed ducts will loosen or become disconnected at joints or connections. Ducts that leak or terminate in attics can cause problems from condensation. Warm, moist air will condense on cold attic framing, insulation and other materials. This condition has the potential to cause health and/or decay problems from mold, or damage to building materials, such as drywall. Moisture also reduces the effectiveness of thermal insulation. 


Mold


Perhaps the most serious consequence of an improper ventilation setup is the potential accumulation of mold in attics or crawlspaces. Mold may appear as a fuzzy, thread-like, cobwebby fungus, although it can never be identified with certainty without being lab-tested. Health problems caused by mold are related to high concentrations of spores in indoor air. Spores are like microscopic seeds, released by mold fungi when they reproduce. Every home has mold. Moisture levels of about 20% in materials will cause mold colonies to grow. Inhaling mold spores can cause health problems in those with asthma or allergies, and can cause serious or fatal fungal infections in those with lung disease or compromised immune systems.


Mold is impossible to identify visually and must be tested by a lab in order to be confidently labeled. Inspectors should refrain from calling anything “mold” but should refer to anything that appears as mold as a material that “appears to be microbial growth.” Inspectors should include in their report, and in the inspection agreement signed by the client, a disclaimer clearly stating that the General Home Inspection is an inspection for safety and system defects, not a mold inspection. Decay, which is rot, is also caused by fungi. Incipient or early decay cannot be seen. By the time decay becomes visible, affected wood may have lost up to 50% of its strength. 


In order to grow, mold fungi require the following conditions to be present:

  • oxygen;
  • temperatures between approximately 45° F and 85° F;
  • food. This includes a wider variety of materials found in homes; and
  • moisture.


If insufficient levels of any of these requirements exist, all mold growth will stop and fungi will go dormant. Most are difficult to actually kill. Even though mold growth may take place in the attic, mold spores can be sucked into the living areas of a residence by low air pressure. Low air pressure is usually created by the expulsion of household air from exhaust fans in bathrooms, dryers, kitchens and heating equipment. 


Improper Ventilation 


Ventilation ducts must be made from appropriate materials and oriented effectively in order to ensure that stale air is properly exhausted.


Ventilation ducts must:

  • terminate outdoors. Ducts should never terminate within the building envelope;
  • contain a screen or louvered (angled) slats at its termination to prevent bird, rodent and insect entry;
  • be as short and straight as possible and avoid turns. Longer ducts allow more time for vapor to condense and also force the exhaust fan to work harder;
  • be insulated, especially in cooler climates. Cold ducts encourage condensation;
  • protrude at least several inches from the roof;
  • be equipped with a roof termination cap that protects the duct from the elements; and 
  • be installed according to the manufacturer's recommendations.


The following tips are helpful, although not required. Ventilation ducts should:

  • be made from inflexible metal, PVC, or other rigid material. Unlike dryer exhaust vents, they should not droop; and 
  • have smooth interiors. Ridges will encourage vapor to condense, allowing water to back-flow into the exhaust fan or leak through joints onto vulnerable surfaces.


Above all else, a bathroom ventilation fan should be connected to a duct capable of venting water vapor and odors into the outdoors. Mold growth within the bathroom or attic is a clear indication of improper ventilation that must be corrected in order to avoid structural decay and respiratory health issues.


Permission granted by InterNACHI. www.nachi.org.

09 Oct, 2023
Check out the recent Redfin article we were featured in:
By MiHome Property Inspections LLC 31 Jul, 2023
Most people don’t know how easy it is to make their homes run on less energy, and here at InterNACHI, we want to change that. Drastic reductions in heating, cooling and electricity costs can be accomplished through very simple changes, most of which homeowners can do themselves. Of course, for homeowners who want to take advantage of the most up-to-date knowledge and systems in home energy efficiency, InterNACHI energy auditors can perform in-depth testing to find the best energy solutions for your particular home. Why make your home more energy efficient? Here are a few good reasons: Federal, state, utility and local jurisdictions' financial incentives, such as tax breaks, are very advantageous for homeowners in most parts of the U.S. It saves money. It costs less to power a home that has been converted to be more energy-efficient. It increases the comfort level indoors. It reduces our impact on climate change. Many scientists now believe that excessive energy consumption contributes significantly to global warming. It reduces pollution. Conventional power production introduces pollutants that find their way into the air, soil and water supplies. 1. Find better ways to heat and cool your house. As much as half of the energy used in homes goes toward heating and cooling. The following are a few ways that energy bills can be reduced through adjustments to the heating and cooling systems: Install a ceiling fan. Ceiling fans can be used in place of air conditioners, which require a large amount of energy. Periodically replace air filters in air conditioners and heaters. Set thermostats to an appropriate temperature. Specifically, they should be turned down at night and when no one is home. In most homes, about 2% of the heating bill will be saved for each degree that the thermostat is lowered for at least eight hours each day. Turning down the thermostat from 75° F to 70° F, for example, saves about 10% on heating costs. Install a programmable thermostat. A programmable thermostat saves money by allowing heating and cooling appliances to be automatically turned down during times that no one is home and at night. Programmable thermostats contain no mercury and, in some climate zones, can save up to $150 per year in energy costs. Install a wood stove or a pellet stove. These are more efficient sources of heat than furnaces. At night, curtains drawn over windows will better insulate the room. Image of a high-efficiency thermostat at the InterNACHI® House of Horrors® in Colorado. 2. Install a tankless water heater. Demand-type water heaters (tankless or instantaneous) provide hot water only as it is needed. They don't produce the standby energy losses associated with traditional storage water heaters, which will save on energy costs. Tankless water heaters heat water directly without the use of a storage tank. When a hot water tap is turned on, cold water travels through a pipe into the unit. A gas burner or an electric element heats the water. As a result, demand water heaters deliver a constant supply of hot water. You don't need to wait for a storage tank to fill up with enough hot water. 3. Replace incandescent lights. The average household dedicates 11% of its energy budget to lighting. Traditional incandescent lights convert approximately only 10% of the energy they consume into light, while the rest becomes heat. The use of new lighting technologies, such as light-emitting diodes (LEDs) and compact fluorescent lamps (CFLs), can reduce the energy use required by lighting by 50% to 75%. Advances in lighting controls offer further energy savings by reducing the amount of time that lights are on but not being used. Here are some facts about CFLs and LEDs: CFLs use 75% less energy and last about 10 times longer than traditional incandescent bulbs. LEDs last even longer than CFLs and consume less energy. LEDs have no moving parts and, unlike CFLs, they contain no mercury. 4. Seal and insulate your home. Sealing and insulating your home is one of the most cost-effective ways to make a home more comfortable and energy-efficient, and you can do it yourself. A tightly sealed home can improve comfort and indoor air quality while reducing utility bills. An InterNACHI energy auditor can assess leakage in the building envelope and recommend fixes that will dramatically increase comfort and energy savings. The following are some common places where leakage may occur: electrical receptacles/outlets; mail slots; around pipes and wires; wall- or window-mounted air conditioners; attic hatches; fireplace dampers; inadequate weatherstripping around doors; baseboards; window frames; and switch plates. Because hot air rises, air leaks are most likely to occur in the attic. 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This type of toilet has a vacuum chamber that uses a siphon action to suck air from the trap beneath the bowl, allowing it to quickly fill with water to clear waste. Vacuum-assist toilets are relatively quiet; and dual-flush toilets. Dual-flush toilets have been used in Europe and Australia for years and are now gaining in popularity in the U.S. Dual-flush toilets let you choose between a 1-gallon (or less) flush for liquid waste, and a 1.6-gallon flush for solid waste. Dual-flush 1.6-GPF toilets reduce water consumption by an additional 30%. 6. Use appliances and electronics responsibly. Appliances and electronics account for about 20% of household energy bills in a typical U.S. home. The following are tips that will reduce the required energy of electronics and appliances: Refrigerators and freezers should not be located near the stove, dishwasher or heat vents, or exposed to direct sunlight. Exposure to warm areas will force them to use more energy to remain cool. Computers should be shut off when not in use. If unattended computers must be left on, their monitors should be shut off. According to some studies, computers account for approximately 3% of all energy consumption in the United States. Use efficient ENERGY STAR-rated appliances and electronics. These devices, approved by the U.S. Department of Energy and the Environmental Protection Agency’s ENERGY STAR Program, include TVs, home theater systems, DVD players, CD players, receivers, speakers, and more. According to the EPA, if just 10% of homes used energy-efficient appliances, it would reduce carbon emissions by the equivalent of 1.7 million acres of trees. Chargers, such as those used for laptops and cell phones, consume energy when they are plugged in. When they are not connected to electronics, chargers should be unplugged. Laptop computers consume considerably less electricity than desktop computers. 7. Install daylighting as an alternative to electrical lighting. 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Change the way you do laundry. Do not use the medium setting on your washer. Wait until you have a full load of clothes, as the medium setting saves less than half of the water and energy used for a full load. Avoid using high-temperature settings when clothes are not very soiled. Water that is 140° F uses far more energy than 103° F for the warm-water setting, but 140° F isn’t that much more effective for getting clothes clean. Clean the lint trap every time before you use the dryer. Not only is excess lint a fire hazard, but it will prolong the amount of time required for your clothes to dry. If possible, air-dry your clothes on lines and racks. Spin-dry or wring clothes out before putting them into a dryer. Homeowners who take the initiative to make these changes usually discover that the energy savings are more than worth the effort. InterNACHI home inspectors can make this process much easier because they can perform a more comprehensive assessment of energy-savings potential than the average homeowner can. 01/30/2023 - Resource: InterNACHI. Permission Granted by InterNACHI - https://www.nachi.org/
By MiHome Property Inspections LLC 31 Jul, 2023
The following items are essential tools, but this list is by no means exhaustive. Feel free to ask an InterNACHI inspector during your next inspection about other tools that you might find useful. 1. Plunger A clogged sink or toilet is one of the most inconvenient household problems that you will face. With a plunger on hand, however, you can usually remedy these plumbing issues relatively quickly. It is best to have two plungers -- one for the sink and one for the toilet. 2. Combination Wrench Set One end of a combination wrench set is open and the other end is a closed loop. Nuts and bolts are manufactured in standard and metric sizes, and because both varieties are widely used, you’ll need both sets of wrenches. For the most control and leverage, always pull the wrench toward you, instead of pushing on it. Also, avoid over-tightening. 3. Slip-Joint Pliers Use slip-joint pliers to grab hold of a nail, a nut, a bolt, and much more. These types of pliers are versatile because of the jaws, which feature both flat and curved areas for gripping many types of objects. There is also a built-in slip-joint, which allows the user to quickly adjust the jaw size to suit most tasks. 4. Adjustable Wrench Adjustable wrenches are somewhat awkward to use and can damage a bolt or nut if they are not handled properly. However, adjustable wrenches are ideal for situations where you need two wrenches of the same size. Screw the jaws all the way closed to avoid damaging the bolt or nut. 5. Caulking Gun Caulking is the process of sealing up cracks and gaps in various structures and certain types of piping. Caulking can provide noise mitigation and thermal insulation, and control water penetration. Caulk should be applied only to areas that are clean and dry. 6. Flashlight None of the tools in this list is of any use if you cannot visually inspect the situation. The problem, and solution, are apparent only with a good flashlight. A traditional two-battery flashlight is usually sufficient, as larger flashlights may be too unwieldy. 7. Tape Measure Measuring house projects requires a tape measure -- not a ruler or a yardstick. Tape measures come in many lengths, although 25 feet is best. Measure everything at least twice to ensure accuracy. 8. Hacksaw A hacksaw is useful for cutting metal objects, such as pipes, bolts and brackets. Hacksaws look thin and flimsy, but they’ll easily cut through even the hardest of metals. Blades are replaceable, so focus your purchase on a quality hacksaw frame. 9. Torpedo Level Only a level can be used to determine if something, such as a shelf, appliance or picture, is correctly oriented. The torpedo-style level is unique because it not only shows when an object is perfectly horizontal or vertical, but it also has a gauge that shows when an object is at a 45-degree angle. The bubble in the viewfinder must be exactly in the middle -- not merely close. 10. Safety Glasses / Goggles For all tasks involving a hammer or a power tool, you should always wear safety glasses or goggles. They should also be worn while you mix chemicals. 11. Claw Hammer A good hammer is one of the most important tools you can own. Use it to drive and remove nails, to pry wood loose from the house, and in combination with other tools. They come in a variety of sizes, although a 16-ounce hammer is the best all-purpose choice. 12. Screwdriver Set It is best to have four screwdrivers: a small and large version of both a flathead and a Phillips-head screwdriver. Electrical screwdrivers are sometimes convenient, but they're no substitute. Manual screwdrivers can reach into more places and they are less likely to damage the screw. 13. Wire Cutters Wire cutters are pliers designed to cut wires and small nails. The side-cutting style (unlike the stronger end-cutting style) is handy, but not strong enough to cut small nails. 14. Respirator / Safety Mask While paints and other coatings are now manufactured to be less toxic (and lead-free) than in previous decades, most still contain dangerous chemicals, which is why you should wear a mask to avoid accidentally inhaling. A mask should also be worn when working in dusty and dirty environments. Disposable masks usually come in packs of 10 and should be thrown away after use. Full and half-face respirators can be used to prevent the inhalation of very fine particles that ordinary facemasks will not stop. 15. Duct Tape This tape is extremely strong and adaptable. Originally, it was widely used to make temporary repairs to many types of military equipment. Today, it’s one of the key items specified for home emergency kits because it is water-resistant and extremely sticky. 01/30/2023 - Resource: InterNACHI. Permission Granted by InterNACHI - https://www.nachi.org/
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