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Library of Things

Books are our brand, but we have other Things to enjoy as well. Delve into the expanded offerings at Fairfax County Public Library. Last Updated: Apr 1, 2024 2:04 PM

Meters & Readers

No, not like people who read like you and me, but as in Things that Read ... Radon levels or Air Quality or what that error message on your car might mean.  If a meter or reader you want is not currently available at your branch, you can place a hold bring the next available meter to your location for convenient pickup.

Circulation Policy

  • Meters may be borrowed for 3 weeks. They are renewable, if there is no wait list.
  • They may be placed on hold using the catalog for pickup at any branch.
  • There are no overdue fines for meters, but if not returned the full replacement cost will be charged to your account.

Air Quality Monitor

This indoor air quality monitor accurately assesses multiple measures of air quality including concentrations of formaldehyde (HCHO), total natural and synthetic volatile organic compounds causing most odors (TVOC), and fine particulate matter <2.5 micron-sized particles (PM2.5) with clock and air quality record chart.

About this item:
  • Replacement Cost: $133.00
    • Meter: $120.00
    • Case: $13.00
  • Model: EG Air Quality Monitor EGVOC-100, case model co2CREA hard case for Fluke62+
Before you begin:
  • Charge device until battery level is at least half full before initial use. Note: You will need to power on device to determine battery level.
  • Place device in a well-ventilated area for 20-60 minutes prior to first use.
How to use:
  • Power on device. Detector will begin initiation process for 3 minutes allowing sensors to preheat and fan to draw in fresh ambient air, which are necessary for accurate results. LED screen will display the countdown number from 180 to 0 seconds.
  • To measure air quality, place device in any location for at least 5 minutes for most accurate and stable readings of formaldehyde (HCHO), TVOC, and PM2.5.
  • With the default overall interface, the time, battery level, air quality level, formaldehyde (HCHO) concentration, Total Volatile Organic Compound (TVOC), and PM2.5/10 concentrations are displayed. 
  • After detection, turn device off and store in a cool, dry place.
Tell me more:
  • Calibration may be required after long periods of storage or prior to first use when testing for formaldehyde or TVOC. This procedure is best done outdoors where formaldehyde and TVOC levels are negligible.
Product guides and information:

EPA's Indoor Air Quality (IAQ)

Battery Tester

image of battery testerUse this meter to test your household batteries to see if they are still good or need to be recycled. No batteries are required for operation and the display will indicate if the remaining charge in the battery is good, low, or replace/recharge. 

About this item:
  • Replacement cost: $13.00 meter and case
    • Meter: $5.00
    • Case: $8.00
  • Model VTechnology BT-168; case ORICO Hard Drive Case 2.5"
Before you begin:
  • Make sure you orient the battery properly with the positive side facing the orange slider.
Product guides and information:

Carbon Monoxide Meter

Image of Carbon Monoxide Meter from Klein ToolsEasy-to-use meter that detects and measures concentration levels of carbon monoxide (ppm) and temperature (Fahrenheit/Celsius).

About this item:
  • Replacement Cost: $109.50
    • Meter: $93.00
    • Case: $16.50
  • Model: Klein ET110, case - Skynew Powerbank hard travel case, medium.
Before you begin:
  • Position yourself in a carbon monoxide-free area before turning on the meter to ensure accurate calibration of the meter.
  • Calibration in an area containing carbon monoxide will result in inaccurately low readings.
How to use:
  • Long-press the POWER button.
  • Press the SET button to perform a 3-minute diagnostic self-test.
  • Place the meter in the area to monitor.
Tell me more:
  • A long press of the MAX/AVE button will clear all previous data.
  • A short press of the MUTE button will stop the active alarm for 3 minutes; a long press will reset the alarm.
Product guides and information:

Kilowatt Usage Meter

Product shot of the Kuman KW-47 usage meterMeasures the amount of electricity used by a particular device to help you understand its power consumption.

About this item:
  • Replacement cost: $34.00 Meter and case
    • Meter $20.00
    • Case $14.00
  • Model: Kuman KW47; case LTGEM EVA hard case
Before you begin:
  • To clear previous data, press the RESET button.
  • Make sure the wattage of the device connecting with this monitor is under 1800W.
How to use:
  • Plug into a wall outlet.
  • Plug device into front of monitor.
  • To set the price function
    • Long press the COST button
    • Press the FUNCTION button to choose the setting position
    • Press the +/- button to chose a number between 0 to 9
    • Press the COST button again to exit the price setting
Tell me more:
  • If the current exceeds 15A or the power exceeds 1800W, the overload alarm icon will flash.
  • Kilowatt usage meters are available from local home improvement stores and online.
  • Meters can be single or multi-plug input as well as wi-fi enabled.
Product guides and information:

Laser Thermometer

Image of Laser Thermometer model IRT206Allows you to safely read temperatures without touching the item being measured. This model is intended for HVAC, ovens, engines, breaker boxes, doors, and many other uses. Not intended for use on people.

About this item:
  • Replacement Cost: $40.00 Thermometer and case
    • Thermometer $27.00
    • Case $13.00
  • Model: General Tools IRT206 or IRT207
  • Uses 9v battery
Before you begin:
  • Not intended for human body temperature measuring.
  • Area being measured will grow with distance from object.
  • TIP: Pets may find the laser guide irresistible, be careful when using near cats.
How to use:
  • Point the unit at the target being measured
  • Pull the trigger and hold.
  • To change between ºC and ºF, press left button beneath screen
  • To turn off / on laser guide, press right button beneath screen.
  • Meter shuts down automatically after a a few seconds (pulling trigger turns on)
Tell me more:
  • This kit includes a simple spot thermometer. Professional level touchless infra-red thermometers are available from various manufacturers.
  • Infra-red thermometers are great for measuring distant, dangerous, rotating, or electrically energized objects where you need a close, but not necessarily exact, measurement. Perfect for most DIYers.
  • These thermometers are available from local home improvement stores and online.
  • Read about the best IR thermometers from a 2020 article at
Product guides and information:

Moisture Meter

Photo of Lkein Tools ET140 moisture meterDetects moisture content in materials, such as drywall, hardwood, masonry, or softwood, letting you know if it is within normal ranges.

About this item:
  • Replacement Cost: $55.00 Meter and case
    • Meter $40.00
    • Case $15.00
  • Model: Klein Tools ET140 meter; Aproca hard storage travel case for ET140
  • Uses 9v battery; requires small phillips head screwdriver to access.
Before you begin:
  • Clear surface dust and debris from area to be measured.
How to use:
  • Power on the meter.
  • Select the mode based on material you are measuring - Drywall, Masonry, Hardwood or Softwood.
  • Scan the material by pressing the sensor against the material you are measuring. 
  • Read the meter; if you want to keep the reading on screen after the meter is removed from the material, select the HOLD button
  • Power off the meter when done. This model does turn off automatically after 10 minutes.
Tell me more:
  • The meter reads moisture content up to 3/4" depth.
  • The LED scale of DRY to WET will display green, yellow, or red bars depending on where in the scale your material falls
  • An OL reading on the screen means the moisture level is Outside the Limit of the meter.
  • An ER reading on the screen indicates an error reading the material or the material is not supported.
  • Moisture meters can be pinless (included in kit) or with pins that require breaking the surface of the material.
  • You can find these at your local home improvement store or online.
Bar graph moisture indicators
DRYWALL 0 to 40% 40 to 70% 70% +
MASONRY 0 to 36% 36 to 63% 63% +
HARDWOOD 0 to 14% 14 to 24.5% 24.5% +
SOFTWOOD 0 to 21% 21 to 39% 39% +
Product guides and information:

On-Board Diagnostic Code Reader

obd2 code readerAn on-board diagnostic II reader (OBD2) reads a car's self-diagnostic codes. It is intended for the intermediate to advanced DIY car care audience.

About this item:
  • Replacement Cost: $86.00
  • Model: Foxwell NT301, with case bundle
Before you begin:
  • Locate your car's data link connector, which should be within 2 feet of the steering wheel. Refer to your car's owners manual.
How to use:
  • Plug reader into your car’s data link connector.
  • Switch the ignition key to the “on” position.
  • Use the navigation arrows on the reader to scroll through the menus.
Tell me more:

Erasing codes may have unintended consequences (i.e. impacting a mechanic’s ability to diagnose a problem, preventing your can from passing an emissions inspection, etc.). Codes should only be erased after the underlying conditions have been repaired.

Product guides and information:

Radon Gas Monitor

image of ecoblu radon monitorDesigned to provide fast, accurate results of the radon level at your house or wherever the EcoBlu monitor is set up. 

About this item:
  • Replacement Cost: $145.99 Meter and Case
    • Meter $130.00
    • Case $15.99
  • Model: EcoBlu EB100
  • Comes with Power cable and power adapter
Before you begin:
  • Since this is a shared resource, you may want to conduct a factory reset to clear any previously recorded data.
    • Press the M button for 10 seconds to enter factory reset mode
    • You will see a countdown RESET 9 --> 8 ... 2 --> 1
    • Data has been erased
  • Placement is important for EcoBlu
    • Place the monitor at least 20" (50cm) above the floor and away from the wall
    • Do not place near open windows or vents
    • Keep away from high heat and humidity
How to use:
  • Plug in the EcoBlu monitor and it will begin collecting data within 10 minutes.
  • You can use different types of monitoring: Real-time (default), Daily, Weekly, Monthly, or Long-term.
    • We recommend Real time or Daily, due to the time constraints of this shared resource.
    • Real-time updates every 10 minutes with an hourly moving average. If the device is powered off, the reading will be auto reset.
    • Daily updates every 24 hours with the last 7 days moving average. First data is available after 24 hours of data points.
Tell me more:

You cannot see, taste, or smell radon, but it could be present. Radon is a leading cause of lung cancer among non-smokers in America. Testing radon levels in your home can prevent unnecessary exposure. Radon gas levels can fluctuate by the hour, day, month, and season. Periodic monitoring during different seasons can be useful. If a high radon level is detected in your home, take steps to fix the problem, including consulting professionals.

Product guides and information:

Soil Meter

soil meter imageThe VIVOSUN Soil Tester measures soil pH, moisture, and light. Use it to select a suitable location for a new plant or to ensure that existing plants are receiving the nutrients they need to thrive.  

About this item:
  • Replacement Cost: $24.70
    • Meter: $9.80
    • Case: $14.90
  • Model: n/a; Caseling for ES-50 scanner
How to use:
  • Use the switch to select the unit you'd like to measure: MOIST, LIGHT, or pH.
  • Insert the prongs 2 - 4 inches into the soil.
  • Adjust the probe until the indicator moves a little.
  • Wait 10 minutes and read the meter.
  • Remove the meter from the soil and wipe clean.
Tell me more:

No battery needed. Please don't leave the meter in soil longer than the recommended testing time.

Product guides and information:

VIVOSUN Soil Tester, 3-in-1 Plant Moisture Meter Light and PH Tester for Home, Garden, Lawn, Farm, Indoor and Outdoor Use, Promote Plants Healthy Growth 

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