Buying guide for best barometers
Every day, the entire weight of the planet’s atmosphere bears down on our bodies, but we rarely notice it. In the same way fish have adapted to the pressures of ocean water, we humans have adapted to the pressures of the air around us. Air pressure affects our lives in many ways, primarily in the formation of weather systems. When air pressure is high, the weather is usually dry and fair, but when air pressure is low, precipitation is more likely, and the temperature drops.
These changes in air pressure can be measured through the use of a weather tool known as a barometer. A barometer is sensitive enough to expand or contract according to an almost imperceptible shift in current conditions. You can use these readings to determine if the weather will improve, remain the same, or take a turn for the worse. Barometers can also be used as altimeters on planes and ships.
It is not unusual to see a barometer packaged with other weather instruments in a comprehensive weather station, but standalone models are certainly available for purchase. If you are looking to invest in a barometer for your home, our in-depth shopping guide can help you make the best decision.
Types of barometers
Barometers have been around since the 17th century, but they have certainly evolved since those earliest days. There are three common types of barometers you might find for sale today: the Torricellian (mercury) barometer, the aneroid barometer, and the electric barometer.
Torricellian (mercury) barometer
The first barometers, still seen today but not very common, use a pool of mercury to measure relative air pressure. A vacuum is created inside a tube partially filled with mercury. The tube is placed in the center of a larger pool of mercury. The atmospheric air pressure pushes down on the pooled mercury, forcing the level in the tube to rise or fall. Gradations on the tube mark the barometric pressure in inches, millimeters, or pascals.
Aneroid barometer
Because mercury is extremely toxic, the original Torricellian barometers have largely fallen out of favor. An aneroid barometer uses a special metallic box that collapses or expands according to atmospheric air pressure. A mechanical spring moves a needle up or down a dial in response to the box’s response. Aneroid barometers are commonly used today.
Altimeter or electronic barometer
Many smartphones and other electronic devices contain a small electronic barometer used primarily to gauge altitude, not weather conditions. A wire embedded in a sensitive “bladder” measures small changes in air pressure and emits an electronic signal. A processor translates that signal into an altimeter reading based on the known air pressures at various heights.
Did you know?
Modern barometers calculate altitude above sea level in addition to measuring air pressure.
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Barometer features
Barometer features
The most simplistic home barometer is a glass globe filled with tinted water. These are more of a novelty than an actual weather tool, but they do show relative shifts in air pressure by a change in water level. It may be challenging to gauge day-to-day changes in barometric pressure with a tool like this, but extreme highs and lows are generally apparent.
Aneroid barometers use a spring mechanism to move a needle across a dial face. Most aneroid barometers include an adjustable pin that marks the first reading, allowing you to interpret future readings as higher or lower. The dial face and numbers should be easy to read, and some calibration should be possible.
Modern mercury barometers usually contain a glass tube with gradations for inches, millimeters, or pascals. You should be able to read the barometric pressure reading in the same way a mercury glass thermometer is interpreted.
Electronic barometers, such as those usually included in a larger weather station, generally show their readings in a digital LCD display.
Casing
Traditional aneroid barometers are often marketed as brass-and-glass reproductions of antique models. The casing is usually a dark hardwood shell with brass fittings and a glass crystal. These barometers are indeed functional, but they are often displayed as part of a nautical or old-world theme.
The glass globe style of barometer is designed to be displayed without a protective casing. The globe may be hung on a wall bracket or included in a set of other decorative weather tools, such as a glass Galilean thermometer or a hygrometer.
Mounting options
Most traditional aneroid barometers are designed to be standalone pieces of functional art, so they are designed like antique desk clocks. Many owners find that a mantle or high shelf is the ideal location for such a piece. However, there are some barometers that can be mounted to the wall with either framing hooks or brackets.
Barometer prices
In a time where detailed weather information is available at a moment’s notice, many standalone aneroid and glass globe Torricellian barometers are considered more decorative than functional. However, there are still occasions in which it’s helpful to be able to detect shifts in air pressure. When shopping for a barometer that is both decorative and functional, here are some price points to consider.
Inexpensive (under $25): At this entry-level price, there are a surprising number of highly decorative barometers to choose from. You will find many glass globe “weather predictors” here. Barometers in this price tier cannot usually be calibrated, but they do offer a broad set of air pressure readings, from low to average to high. There are some brass-and-glass aneroid models that provide fairly accurate information for less than $25, and there are many inexpensive plastic reproductions of the same.
Mid-range ($25 to $75): Aneroid barometers at this price are generally well-constructed from authentic components such as hardwood, brass, and glass. Many can be calibrated for accuracy. Modern glass globe barometers in this price tier are often displayed as pieces of functional art, either alone or as part of a larger weather prediction set. This is also the price range where electronic barometers become more common.
Expensive (over $75): High-end aneroid barometers are usually quality reproductions of classic desktop or wall-mounted antique models. The internal mechanism is extremely sensitive to changes in air pressure, and the display dial is very detailed. Electronic barometers designed for commercial applications are also available in this price range.
Tips
- The placement of a barometer can affect its accuracy. Avoid placing a functional barometer near air conditioning, as the circulating air could change the air pressure around the device.
- Many aneroid and mercury barometers are rated for indoor use only. Exposure to the elements could affect their performance drastically.
- Some aneroid and electronic barometers can be calibrated for greater accuracy. Consider using an online weather service to find the current air pressure reading for calibration purposes.
- Tapping the glass face of an aneroid barometer is an essential step. The internal mechanism may not react without this action.
Other products we considered
AcuRite’s Galileo Thermometer with Glass Globe Barometer is an attractive combination of a fluid-filled Galileo thermometer and a glass globe barometer. The water level in the barometer’s spout rises or falls according to ambient air pressure. Ambient Weather’s Wall-Mount Liquid Barometer also uses a freestanding glass globe filled with tinted water to indicate relatively high or low air pressure. When air pressure is especially high, the fluid will actually pour out of the spout and into a drip cup.
For those who seek a modern take on barometers, we recommend TecScan’s FUNcaster Barometer Ambient Weather Clock. This compact unit displays air temperature, air pressure, and relative humidity using miniature but extremely accurate electronic sensors.
FAQ
Q. I have an antique barometer sitting on my mantle. How accurate can I expect it to be?
A. Many older barometers were designed to be functional as well as decorative, so there’s every chance your antique barometer is still fairly accurate. You may need to recalibrate it (if possible), but the mechanism inside should still be reacting to atmospheric pressure as designed.
Q. I check my barometer several times a day, but I don’t see many obvious changes in the readings. Am I doing something wrong?
A. Barometer readings may not vary much on days when a high or low air pressure system is firmly in place. This is normal. You’re more likely to see a dramatic change when a cold or warm front moves in and replaces the current system.
Q. Why doesn’t my local TV meteorologist mention barometric pressure very often?
A. Actual barometric pressure readings do not provide viewers with a broad overview of present or future weather conditions. TV meteorologists often focus more on the movements of fronts or pressure systems. At home, changes in barometric pressure are more useful, because users can measure changes in real time and create their own forecast.
