6. Using Steam to Eliminate Bed Bugs

DRAFT
This document is not final and is subject to change.

Commercial steam cleaning machines can achieve the lethal temperatures needed to kill bed bugs. Dry heat of 122°F is immediately lethal to bed bugs (desiccation), but due to moisture and quick evaporation, steam must bring the surface temperature to within a range of 160°F – 180°F to kill bed bugs. Dry steam (low moisture) is preferable but such outputs are only available with commercial steam machines designed for deep cleaning. If you are choosing a steamer for bed bug control, be sure to confirm that the steam output temperature is high enough for the job.

Compared to dry heat’s ability to penetrate cracks and crevices within an enclosed space, use of steam is a targeted approach requiring more precision, time, and effort to be effective. Nevertheless, steam is an important tool in the IPM toolbox for managing bed bugs on mattresses, box springs, rugs, and plush furniture, such as sofas.

Things to Know About Steam Machines

Steam machines come in a variety of forms and functionalities. The steam machine market expanded greatly after it was recognized that steam can be used for bed bug treatments. But device performance may vary based on the model.

Some desirable qualities in a steam machine include:

  • "For Commercial Use": Most steam machines built for commercial use reach temperatures of 200°F or more, instantly killing bed bugs. Using methods described in the “Heat– Hair Dryer” section, test the steam machine to make sure temperatures reach at least 160-180°F.
  • Length of continuous steam: The ability to produce steam over a long period of time is important. Less expensive machines may reach the lethal temperature but operate for a short period of time, forcing the user to stop frequently. This may be OK for an individual or for a few items, but pest management professionals should seek machines with greater continuous steam times (45 minutes).
  • Large water capacity: Steam machines vary in the amount of water they can carry. Higher capacity means fewer refills. A one-gallon tank is recommended for DIY home use. Pest management professionals should consider steamers with high water capacity and a continuous-flow feature, so fresh water can be added while the machine is in operation.
  • Steam volume control: Some machines offer steam volume control to limit the amount of moisture. This helps to protect items that can retain or be damaged by excess moisture. Look for machines featuring low vapor flow and high temperatures.
  • Multiple attachments: Like vacuum cleaners, steam machines often come equipped with various attachments for specific jobs. A flat square or triangle-shaped upholstery attachment should be included for treating furniture. Look for a carpet attachment and a crack-and-crevice tool. Place a small towel over the steam head to reduce air pressure (avoid blowing bed bugs around) and to increase heat development.

Avoid steam machines designed for clothing, carpet steamers, non-portable units, or poorly made brands. For the greatest efficiency, use the correct tool for the job.

What You Need to Use Steam:

  • Commercial steam machine for cleaning
  • Meat thermometer to measure temperature output
  • Multiple attachments for different sizes and shapes of harborage
  • Hand towel or cotton cloth

How to Use Steam

It is generally accepted that longer treatment time is better. “Slow and Steady” is the rule for steam treatments. One study found that 10 to 30 seconds per foot was sufficient to kill all stages of bed bugs and their eggs on upholstered furniture.

  1. First, use a meat thermometer to first measure the steam machine’s temperature output. Aim for a temperature of over 160°F.
  2. Prepare the steam machine as described in the product guide (fill water, plug in device, allow to warm, etc.).
  3. Attach the appropriate nozzle to the device (generally the triangular-shaped upholstery nozzle).
  4. Test a small portion of the item to identify any risks of damage from the treatment and determine if steam is an option.
  5. Slowly (10-30 seconds per foot) move the applicator over the area. If infested, there will be live bugs, feces, and eggs in the furniture’s cracks and crevices—ideal bed bug harborage. Keep in mind that steam dissipates and cools the further it gets from the applicator, so keep the nozzle within ¼ inch of the infested item, or in direct contact. If live bugs are present, direct contact may cause them to disperse, so you might consider vacuuming to remove live bugs before a steam treatment.
  6. Allow the treated area to dry. Remove dead bugs and eggs with a vacuum. If treating a mattress or box spring, consider using an encasement only after it has dried to avoid the development of mold.
Vacuum cleaner and accessories.
Fig. 65. Choose a steamer carefully, making sure it generates enough heat to kill bed bugs.
Various attachments for Vacuum
Fig. 66. Various attachments can help you apply steam to different types of furniture and materials.
An upholstery attachment for a steam cleaner can.
Fig. 67. An upholstery attachment for a steam cleaner can.
Wooden Ruler.
Fig. 68. Steam the material at 10-30 seconds per foot, or until the material reaches 160F.
Professional steaming sofa cushion.
Fig. 69. Steam treatment of a fabric sofa takes time but can be very effective.
Triangular upholstery nozzle being used with a steamed towel.
Fig. 70. The triangular upholstery nozzle can be wrapped in a cotton cloth to help build up heat. Photo by R. Cooper.

Consider This:

  • Sensitive Items: The combination of heat and moisture has been shown to damage certain items, so steam is not a viable option for many infested items. Before performing a treatment, perform a test on an inconspicuous area for the following and similar items:
    • Leather/suede
    • Acrylic
    • Vinyl
    • Linen, silk
    • Painted surfaces
    • Finished wood
    • Laminated wood
    • Simulated wood veneers
    • Plastic
    • Wallpaper and other glued surfaces
  • Attachment or Nozzle Type: As described above, various attachments or nozzles will be included with most steam machines. In general, the upholstery attachment (triangle shaped) is used to concentrate steam in a smaller area. The carpet attachment is often too big and requires slower treatment time.
  • A benefit of the upholstery nozzle is that it tends to regulate the steam pressure. Too much pressure can blow bed bugs off without killing them so take note when using steam, and adjust accordingly.
  • Penetration: Unlike dry heat that is able to penetrate cracks and crevices, steam at lethal temperatures is thought to have low penetration. Specifically, steam can penetrate 2 ⅜ inches (6 centimeters) into a crack/crevice, and less than one inch beneath fabric surface.
  • Professional Use: A quality steam machine can be expensive, and is not a tool commonly employed by individuals. However, organizations and businesses may wish to invest in a steam machine if they are constantly faced with bed bug introductions. Hospitals, group homes, shelters, universities/colleges, and others can use steam machines to treat commonly infested items or areas.

Advantages and Disadvantages of Steam:

  • Advantages: Pesticides are not always effective against bed bug eggs, and usually require two treatments. Steam and other high-temperature treatments, however, kill all life stages, including eggs, in a single treatment. Furthermore, because pesticides are not used, there is no concern about chemical residues on surfaces. To date, there is no documented resistance to steam treatments.
  • Disadvantages:
    • Possible damage to items (see Consider This above).
    • Moisture damage to items: Development of mold if wet items are encased or covered in bed sheets.
    • No residual: Like dry heat, steam provides control for a moment in time that does not last after the treatment is completed.
    • Equipment issues: One study demonstrated that the duration of treatment can reduce the output of the steam machine. As a result, the temperature generated and the ability to kill bed bugs was diminished with longer use.

References for Using Steam to Eliminate Bed Bugs

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