- Measures indoor temperature (Fahrenheit or Celsius) and humidity
- Humidity level icon indicates high, low, or ideal indoor conditions
- Daily high and low temperature and humidity records
- Totally wireless tabletop and magnet-mountable design
- Powered by one (1) AA battery (not included)
Indoor Temperature and Humidity Monitoring
Maintaining ideal humidity levels for your rooms has significant skin, allergen and other health benefits by preventing the growth of mold, bacteria, viruses, fungi, mites, and other asthma-inducing agents in your home.
The AcuRite Digital Temperature and Humidity Monitor allows you to quickly and easily check comfort conditions with professional-level humidity and temperature sensors. The home comfort icon conveys whether humidity levels are too low, too high, or ideal based on Relative Humidity (RH) readings so you can adjust room humidity levels to protect your possessions and improve room comfort.
It's more than accurate, it's AcuRite.
By dwayne
I purchased two of these as I wanted something digital and I liked that it recorded the highs and lows for each: humidity and temperature. Right out of the package they both read identical humidity and temperature which was great. I then brought them to my work and put them in a stabilty chamber to test against a calibrated expensive humidty guage at 63.3% RH and 25.x C. Both units measured within a single percent of RH and ready 25 C. I then calibrated the units in a nitrogen filled instrument with a calibrated unit. The calibrated unit read 0.0 % RH while both units read 16. I figured out that these units DO NOT work below 20 % RH and instead display 16 %. I then tested them in open rooms compared to a calibrated unit at 20-30% RH and these babies read within a single unit of % RH and about 0.5 degrees C. I have no way of calibrating them higher and not sure how high they will read accurately but I'm curious to see what they'll read outside in the rain. Otherwise they are great units for the price.
By A. Burton
Just bought this and the AcuRite 00325. This 613A1 seems more accurate out of the box and responds to temp/humidty changes faster. It's also smaller and better looking in my opinion. It's numbers seem right on, both temp and humidity. It has a magnet and a clip which doubles as a kickstand on the back. The picture was taken after several hours. The differences in the numbers between the two units has been consistent, humidity about 3% different and temp 2 degrees different.
By Jeff Geerling
I've now purchased two of these humidity monitors; so I can monitor humidity in the basement. Both monitors, if kept next to each other, they're within 1% of each other for the humidity measurement, and within 2 degrees Fahrenheit of each other for temperature measurement. Pretty close, and accurate to within a degree of my other thermometers.
It's important to keep an eye on humidity levels in both the summer and winter; in the summer, you should keep your humidity level below 60% to reduce mold buildup, and below 50% to reduce the chance of dust mites. During the winter, try to keep your humidity between 30-40% to reduce mold buildup, and to prevent dry air which can cause throat and nose irritation (it helps me avoid waking up with a bloody nose in the winter).
The fact that this little device is so compact and has both a stand and a magnet for placing it almost anywhere makes it an easy purchase over most other monitors. I also like how it shows the past day's highs and lows.
Excellent product--it's not industrial grade in any way, but it's not made for factories--it's made to stick on your fridge or on your desk.
It's important to keep an eye on humidity levels in both the summer and winter; in the summer, you should keep your humidity level below 60% to reduce mold buildup, and below 50% to reduce the chance of dust mites. During the winter, try to keep your humidity between 30-40% to reduce mold buildup, and to prevent dry air which can cause throat and nose irritation (it helps me avoid waking up with a bloody nose in the winter).
The fact that this little device is so compact and has both a stand and a magnet for placing it almost anywhere makes it an easy purchase over most other monitors. I also like how it shows the past day's highs and lows.
Excellent product--it's not industrial grade in any way, but it's not made for factories--it's made to stick on your fridge or on your desk.
By The hvac
Good product bought 4 all were the same, for $10 great deal, a very good humidistat would cost $100. I compared all 4 together after 2 hours they were all the same, even though two are off by one it is more like .2 after the photo I started to move one when I came back they were all reading the same.
By Gourmet Chuckaroo
I bought a whole house humidifier but could not tell what was happening in rooms other than where it is sitting. Thought this might help me monitor the situation. My house has a heat pump and when it is cold, the system runs most of the time causing the air to become very dry and my nasal passages to dry up and dive me bananas. I bought one of these items and then bought two more so I could monitor the humidty throughout the house.
There are neat little gadgets with a magnet or a stand on the back that really work well and provide you with an accurate humidity reading, high and low for the past 24 hours and temperature with high and low for the past 24 hours. My checking has indicated that they are very accurate (within about 1-3% relative humiity).
There are neat little gadgets with a magnet or a stand on the back that really work well and provide you with an accurate humidity reading, high and low for the past 24 hours and temperature with high and low for the past 24 hours. My checking has indicated that they are very accurate (within about 1-3% relative humiity).
By Aggie
I read all the reviews for the Acurite 00613A1 and 00325. I contacted AcuRite to determine the difference in the two models. I thought one was an older model, which is not true. Both were created at the same time, however the 00325 was bigger. I went with this design, and I'm very happy with it for the price! It's small but still easy to read. I purchased 3 and have them placed in bedrooms and a home office, which all seem to be too hot in the summer and too cold in the winter. As others have stated in reviews here, the temperature readings on these monitors are not 100% accurate. With all three placed side-by-side, as you can see in the picture, the temp. reading is one degree lower on one unit. When I first purchased these, they were a few degrees off. But after having them in the house for a couple of months, they seem to be fairly close in their measurements. The highs and lows in this picture are different, because I keep them in different rooms. For the price, you can't go wrong with this purchase!
By AmaAddict
I'm using this to keep track of the temperature and humidity in a chinchilla enclosure. Chinchillas (the Andes rodents) are extremely sensitive to heat and humidity, so it's important to keep their temperature correct. I've tested this unit against a hygrometer we use in my lab (calibrated, regularly tested) and it compares perfectly well with that one.
The 24-hour high/low is extremely nice, since at a glance I can make sure that the chinchillas haven't been outside of their normal range in the last day, although I think it keeps the high/lows for a bit longer than 24 hours. I haven't timed it exactly, but it seems to be the high/low for the last 36 hours.
The clip is triple purpose - clip, magnetic, and stand. My only complaint is that the spring in the clip isn't secured very well and if you drop the unit, as I have unfortunately, the clip will spring out of place. It's easy enough to fix, as long you have pretty good strength and dexterity in your fingers.
Other than that, this is an excellent unit if you need a good way to watch the temperature and humidity that a pet is exposed to.
The 24-hour high/low is extremely nice, since at a glance I can make sure that the chinchillas haven't been outside of their normal range in the last day, although I think it keeps the high/lows for a bit longer than 24 hours. I haven't timed it exactly, but it seems to be the high/low for the last 36 hours.
The clip is triple purpose - clip, magnetic, and stand. My only complaint is that the spring in the clip isn't secured very well and if you drop the unit, as I have unfortunately, the clip will spring out of place. It's easy enough to fix, as long you have pretty good strength and dexterity in your fingers.
Other than that, this is an excellent unit if you need a good way to watch the temperature and humidity that a pet is exposed to.
By OpenPenman
this thing is tiny, i mean it could fit in your fist like a baseball. 2x the size of a standard beeper. It could be carried around, it's lightweight, it takes one singular AA battery, it has a clip, and a big magnet behind the clip which is tremendously useful/
I haven't salt testing feeling it reads nicely when I'm in the room and can feel the temp and humidity value to be fair and realistic.
It also shows an ongoing low and high value for temp and humidity. Not too sure if this is over a 24 hour measurement or the electronic lifetime. Maybe the distributor can verify. Besides that, this digital reader is great compared to another type of analog hygrometer that I owned which needed constant salt testing. I wouldn't use it for extremely humid environments in fear of water damaging the unit, in fear of abusing it's limited potential, but if you decide to, I believe the plastic casing is tight enough to deal with and screen out any water damage in comparison to metallic/or copper hygrometers that become rusted and stained over time.
I haven't salt testing feeling it reads nicely when I'm in the room and can feel the temp and humidity value to be fair and realistic.
It also shows an ongoing low and high value for temp and humidity. Not too sure if this is over a 24 hour measurement or the electronic lifetime. Maybe the distributor can verify. Besides that, this digital reader is great compared to another type of analog hygrometer that I owned which needed constant salt testing. I wouldn't use it for extremely humid environments in fear of water damaging the unit, in fear of abusing it's limited potential, but if you decide to, I believe the plastic casing is tight enough to deal with and screen out any water damage in comparison to metallic/or copper hygrometers that become rusted and stained over time.
By Westsoc
The first question ask by users of AcuRite humidity monitor is how accurate is the reading of relative humididty (RH) especially when the spec for RH is +-4% due to unit to unit variation. (Obviously, the company would like to ship all units they made to make more money. Tighter spec causes high rejects and the company will make less money or the cost for the AcuRite will have to go up.) Also the accuracy could degrade over time due to contamination of the humidity detector. There is no way for users to find out if they have bought an accurate monitor or one that is 4% or more off unless they do a two point calibration at room temperature using two saturated (with some undissolved salt left at the bottom) salt solutions each sealed in a ziplock bag together with the monitor. This is very easy to do for anyone. Just put the AcuRite in the sealed bag overnight then check the RH reading the next morning and you are done. Fortunately, the needed salts are also easy to come by as one is table salt (sodium chloride; the monitor should read 75% RH at 70 deg F) and the other could be driveway ice melt (calcium chloride; the monitor should read 31.5% RH at 70 deg F). Since bacteria could not grow in such salty solution, the sealed saturated solutions could be saved and reused over and over again allowing re-calibration whenever the user desires. I used two ziplock bag, each of which has two plastic cups. In one of these bags, each cup has 1/8 inch of water on top of 1/8 inch of undissolved table salt. Likewise, in the other bag each cup has saturated driveway ice melt solution.
The procedures I used to do a comprehensive calibration are given below.
Using these two saturated solutions, my measurements on the AcuRite I bought showed that for temperature from 39 deg F to 79 deg F and for relative humidity from 29% to 75% , the max error is 3% off in humidity occurred at very low temperature (39 deg F) (i.e 37%RH is actually 40%) and near room temperature, the error is only 1%RH. (Lucky me!)
Actually, the AcuRite is both a digital humidity monitor (hygrometer) and a digital thermometer. The AcuRite I tested is surprising accurate over a practical range of temperatures and a practical range of relative humidity values (see details given below). The temperature reading is also quite accurate. It is very desirable to have a high accuracy humidity monitor and thermometer for use at home. In the summer, a high humidity house is uncomfortable. Worse yet, a humid basement smells foul allowing mold to grow and humid closets cause clothes to smell bad - a nightmare for many housewives. Knowing accurately the humidity allows one to take measure to lower it. With seemingly high accuracy, the AcuRite is surprisingly cheap.
The comfortable relative humidly(RH) range to human body is recommended to be a region around 45%. American Society of Heating, Refrigerating and Air-conditioning Engineers Inc. (ASHRAE) recommends:
---RH ---------temperature ---- season
30- 60%----- 68-75degF -------winter
30- 60%----- 73-79degF ------summer
"Elevated relative humidity can promote the growth of mold, bacteria, and dust mites, which can aggravate allergies and asthma" and "Relative humidity levels above 70% may lead to the development of condensation on surfaces and within the interior of equipment and building structures. Left alone, these areas may develop mould and fungi." Typically, room temperature is set at 70degF. Also I preferred a RH of 50%. At 45%RH, I feel dry and my skin starts to wrinkle.
Sodium Chloride saturated solution is commonly used to calibrate a hygrometer (humidity monitor) at room temperature (70 deg F) which should give 75%RH. Thus the hygrometer needs to be calibrated again with another source with lower RH, such as Calcium Chloride (31.5% RH at 70 deg F) or Magnesium Chloride (33%RH at 70 deg F). If the hygrometer agrees with one of these values then one can assume it is accurate around 50% RH. If the hygrometer is used only at room temperature, it only needs to be calibrated by two saturated solutions (for example sodium chloride and calcium chloride). However, I have calibrated from 39 to 79 deg F.
Table salt (sodium chloride) and driveway ice melt (calcium chloride) provide an inexpensive and convenient way to calibrate (or check accuracy) of a hygrometer over a range of temperatures and humidity values. I have calibrated my AcuRite unit by using sodium chloride and calcium chloride saturated solutions, each of which was placed in a ziplock bag together with the AcuRite.
An accurate hygrometer is expensive and bulky and I was surprised at the seemingly high humidity accuracy of the Acurite which I purchased from Amazon. The attractive features of the AcuRite are: seemingly very accurate humidity and temperature readings across a useful range of humidities and temperatures(see calibrations given below), records the max and min humidity and temperature occurred within 24 hr interval and low cost. Also the display font for humidity is large enough for convenient viewing. These features are not expected from a $10 device.
Calibration using saturated table salt (sodium chloride) solution
Calibration is based on published measurements of equilibrium relative humidity(RH) vs temperatures above saturated salt solution by scientist(s). I will use these published RH values as standard. For table salt saturated solution, the published RHs, given below, surprisingly are almost a constant from 32 to 104 degF(the measurement increment was 5 degC).
Temp (deg F) RH(%)
32-59 76
68-104 75
I found that there was no different from using table salt with and without iodine. So I used the former. I also found that salt slurry did not work well. I sealed the AcuRite and two plastic cups in a ziplock bag which was further sealed by Scott tape. Each cup has at least 1/8 inch of undissolved salt (at the highest temperature of measurement) with at least 1/8 inch of water above it. Each deg F change can cause 3% change in RH. Since the AcuRite with battery is a big thermal mass, I made sure that for each measurement, the temperature and RH were stable for at least 1/2 hr, a condition which turned out to be most difficult to meet. Measurement results are given below. I found that for temperature, the AcuRite seems to be about 1 deg F higher than another temperature meter which has fractional deg F. However, I will use the temperature displayed by the AcuRite. Low temperature measurements were taken in a refrigerator. It took about one week to do all the measurements.
Temp (deg F) RH(%, measured) RH(%, from standard) Error(%)
41 74 76 -2
72 75 75 0
75 77 75 +2
77 76 75 +1
88 77 75 +2
90 76 75 +1
From the above table, at room temperature of 72 deg, the error is zero and from 41 to 90 deg F, the max error is 2%RH. I would say this is quite acceptable for home use. Next, I checked if the humidity is linear over a range of RH values and a range of temperatures by using another saturated salt solution.
Calibration using saturated calcium chloride (CaCl2) solution at low humidity
A better and purer source for calibration at low humidly is magnesium chloride. Over its saturated solution, the RH is 33% over practical temperature range. Pure Magnesium Chloride is available from amazon or ebay sellers. Another good source to use is Potassium Carbonate which another reviewer in this forum had used and which is also available from amazon or ebay. The equilibrium RH is 43% from 0 to 30 degC. However, I didn't want to spend the money and trouble to get them.
I found that I have some Prestone Driveway Heat ice melter (available from Home Depot and Lowes) which turned out to be Calcium Chloride. But the purity of the source was unknown and this would cast doubt on the results. From the internet, I found that the published equilibrium relative humidity(RH) vs temperatures above saturated calsium chloride solution are:
Temp (deg F) 41 50 59 68 77
RH(%) 40.0. 38.0. 35.0. 32.0 29.5
RH vs temp seems to be linear and the slope is bout -0.3%RH per deg F
My measurement results are:
Temp (deg F) RH(%, measured) RH(%, from standard) Error(%)
39 37 ~40 -3
79 28 ~29 -1
Thus at each temperature, there are now two data points.
If the calcium chloride measurements were believable due to the unknown purity of the calcium chloride source, then the linearity of the humidity of Acurite over a temperature range from 39 to 79 deg F and over a humidity range from 29% to 75% is quite good for home use as the max error is less than 3%RH occurred at 39 deg F, which is too low for normal use. Near Room temperature , however, the error is about 1%RH, which is remarkably small.
I believe that the humidity detector is polymer on a capacitor. Capacitor is a linear device and should response linearly to humidity absorbed. Thus for each temperature if two measured data points agreed with published data by other scientists, then it is sufficient to determine the accuracy and linearity at that temperature. I have verified the data agreement from 39 to 79 deg F. (Note that the calcium chloride purity is questionable. But the measured data did agree with published values.) Thus, within this temperature range, the AcuRite unit I bought seems to be accurate and linear. Ideally, one would like to further calibrate the unit with magnesium nitrate saturated solution which has a RH of 50-55% across practical temperatures. This would give three data points on a straight line to verify the linearity. However, I do not know how to get it easily and cheaply.
In Summary: for temperature from 39 deg F to 79 deg F and relative humidity from 29% to 75% , the max error is 3% off in humidity occurred at very low temperature (39 deg F) (i.e 37%RH is actually 40%) and near room temperature, the error is only 1%.
Max humidity
After I wrapped the AcuRite in a wet paper tower, the humidity was 99%, the expected value.
Update rate and modify the back cover to increase airflow through the unit
For normal use, no modification is need as modification does not change the accuracy of humidity and temperature. Allowing more airflow than necessary may shorten the life of the unit by quicken the contamination of the humidity detector inside the unit. Modification only changes the response time when the humidity changes. For home use, the humidity and temperature are not expected to change so fast that the unit could not keep up.
The unit updates the humidity and temperature about every 15 sec. After initial testings which showed that the unit was accurate, I invested time to modify the cover of the unit as the airflow through the unit is through a grill and could be increased to have a faster response time. Steps for the modification are given below:
1) The cover is held by 4 small screws. Remove them by a jewelry screw driver.
2) Separate the back cover from the main body gently and not too far apart as there is a ground wire of the battery housing connecting the two.
3) Remove the ground wire from the battery housing. Now the two parts can be separated.
4) There is a plastic stick used for changing deg C to deg F. It will fall out but is easy to put back during re-assembly.
I drilled four 3/16 inch holes on each side of the back cover as well as one 3/16 inch at the center of the back cover.
The above measurements were done on just one AcuRite which I bought. Because measured data points seem to agree with published values by other scientists, I am satisfied that the humidity and temperature of my unit are accurate and use it with confidence. However, beware that there are a large number of reviews in this forum who said their AcuRite is no good.
The procedures I used to do a comprehensive calibration are given below.
Using these two saturated solutions, my measurements on the AcuRite I bought showed that for temperature from 39 deg F to 79 deg F and for relative humidity from 29% to 75% , the max error is 3% off in humidity occurred at very low temperature (39 deg F) (i.e 37%RH is actually 40%) and near room temperature, the error is only 1%RH. (Lucky me!)
Actually, the AcuRite is both a digital humidity monitor (hygrometer) and a digital thermometer. The AcuRite I tested is surprising accurate over a practical range of temperatures and a practical range of relative humidity values (see details given below). The temperature reading is also quite accurate. It is very desirable to have a high accuracy humidity monitor and thermometer for use at home. In the summer, a high humidity house is uncomfortable. Worse yet, a humid basement smells foul allowing mold to grow and humid closets cause clothes to smell bad - a nightmare for many housewives. Knowing accurately the humidity allows one to take measure to lower it. With seemingly high accuracy, the AcuRite is surprisingly cheap.
The comfortable relative humidly(RH) range to human body is recommended to be a region around 45%. American Society of Heating, Refrigerating and Air-conditioning Engineers Inc. (ASHRAE) recommends:
---RH ---------temperature ---- season
30- 60%----- 68-75degF -------winter
30- 60%----- 73-79degF ------summer
"Elevated relative humidity can promote the growth of mold, bacteria, and dust mites, which can aggravate allergies and asthma" and "Relative humidity levels above 70% may lead to the development of condensation on surfaces and within the interior of equipment and building structures. Left alone, these areas may develop mould and fungi." Typically, room temperature is set at 70degF. Also I preferred a RH of 50%. At 45%RH, I feel dry and my skin starts to wrinkle.
Sodium Chloride saturated solution is commonly used to calibrate a hygrometer (humidity monitor) at room temperature (70 deg F) which should give 75%RH. Thus the hygrometer needs to be calibrated again with another source with lower RH, such as Calcium Chloride (31.5% RH at 70 deg F) or Magnesium Chloride (33%RH at 70 deg F). If the hygrometer agrees with one of these values then one can assume it is accurate around 50% RH. If the hygrometer is used only at room temperature, it only needs to be calibrated by two saturated solutions (for example sodium chloride and calcium chloride). However, I have calibrated from 39 to 79 deg F.
Table salt (sodium chloride) and driveway ice melt (calcium chloride) provide an inexpensive and convenient way to calibrate (or check accuracy) of a hygrometer over a range of temperatures and humidity values. I have calibrated my AcuRite unit by using sodium chloride and calcium chloride saturated solutions, each of which was placed in a ziplock bag together with the AcuRite.
An accurate hygrometer is expensive and bulky and I was surprised at the seemingly high humidity accuracy of the Acurite which I purchased from Amazon. The attractive features of the AcuRite are: seemingly very accurate humidity and temperature readings across a useful range of humidities and temperatures(see calibrations given below), records the max and min humidity and temperature occurred within 24 hr interval and low cost. Also the display font for humidity is large enough for convenient viewing. These features are not expected from a $10 device.
Calibration using saturated table salt (sodium chloride) solution
Calibration is based on published measurements of equilibrium relative humidity(RH) vs temperatures above saturated salt solution by scientist(s). I will use these published RH values as standard. For table salt saturated solution, the published RHs, given below, surprisingly are almost a constant from 32 to 104 degF(the measurement increment was 5 degC).
Temp (deg F) RH(%)
32-59 76
68-104 75
I found that there was no different from using table salt with and without iodine. So I used the former. I also found that salt slurry did not work well. I sealed the AcuRite and two plastic cups in a ziplock bag which was further sealed by Scott tape. Each cup has at least 1/8 inch of undissolved salt (at the highest temperature of measurement) with at least 1/8 inch of water above it. Each deg F change can cause 3% change in RH. Since the AcuRite with battery is a big thermal mass, I made sure that for each measurement, the temperature and RH were stable for at least 1/2 hr, a condition which turned out to be most difficult to meet. Measurement results are given below. I found that for temperature, the AcuRite seems to be about 1 deg F higher than another temperature meter which has fractional deg F. However, I will use the temperature displayed by the AcuRite. Low temperature measurements were taken in a refrigerator. It took about one week to do all the measurements.
Temp (deg F) RH(%, measured) RH(%, from standard) Error(%)
41 74 76 -2
72 75 75 0
75 77 75 +2
77 76 75 +1
88 77 75 +2
90 76 75 +1
From the above table, at room temperature of 72 deg, the error is zero and from 41 to 90 deg F, the max error is 2%RH. I would say this is quite acceptable for home use. Next, I checked if the humidity is linear over a range of RH values and a range of temperatures by using another saturated salt solution.
Calibration using saturated calcium chloride (CaCl2) solution at low humidity
A better and purer source for calibration at low humidly is magnesium chloride. Over its saturated solution, the RH is 33% over practical temperature range. Pure Magnesium Chloride is available from amazon or ebay sellers. Another good source to use is Potassium Carbonate which another reviewer in this forum had used and which is also available from amazon or ebay. The equilibrium RH is 43% from 0 to 30 degC. However, I didn't want to spend the money and trouble to get them.
I found that I have some Prestone Driveway Heat ice melter (available from Home Depot and Lowes) which turned out to be Calcium Chloride. But the purity of the source was unknown and this would cast doubt on the results. From the internet, I found that the published equilibrium relative humidity(RH) vs temperatures above saturated calsium chloride solution are:
Temp (deg F) 41 50 59 68 77
RH(%) 40.0. 38.0. 35.0. 32.0 29.5
RH vs temp seems to be linear and the slope is bout -0.3%RH per deg F
My measurement results are:
Temp (deg F) RH(%, measured) RH(%, from standard) Error(%)
39 37 ~40 -3
79 28 ~29 -1
Thus at each temperature, there are now two data points.
If the calcium chloride measurements were believable due to the unknown purity of the calcium chloride source, then the linearity of the humidity of Acurite over a temperature range from 39 to 79 deg F and over a humidity range from 29% to 75% is quite good for home use as the max error is less than 3%RH occurred at 39 deg F, which is too low for normal use. Near Room temperature , however, the error is about 1%RH, which is remarkably small.
I believe that the humidity detector is polymer on a capacitor. Capacitor is a linear device and should response linearly to humidity absorbed. Thus for each temperature if two measured data points agreed with published data by other scientists, then it is sufficient to determine the accuracy and linearity at that temperature. I have verified the data agreement from 39 to 79 deg F. (Note that the calcium chloride purity is questionable. But the measured data did agree with published values.) Thus, within this temperature range, the AcuRite unit I bought seems to be accurate and linear. Ideally, one would like to further calibrate the unit with magnesium nitrate saturated solution which has a RH of 50-55% across practical temperatures. This would give three data points on a straight line to verify the linearity. However, I do not know how to get it easily and cheaply.
In Summary: for temperature from 39 deg F to 79 deg F and relative humidity from 29% to 75% , the max error is 3% off in humidity occurred at very low temperature (39 deg F) (i.e 37%RH is actually 40%) and near room temperature, the error is only 1%.
Max humidity
After I wrapped the AcuRite in a wet paper tower, the humidity was 99%, the expected value.
Update rate and modify the back cover to increase airflow through the unit
For normal use, no modification is need as modification does not change the accuracy of humidity and temperature. Allowing more airflow than necessary may shorten the life of the unit by quicken the contamination of the humidity detector inside the unit. Modification only changes the response time when the humidity changes. For home use, the humidity and temperature are not expected to change so fast that the unit could not keep up.
The unit updates the humidity and temperature about every 15 sec. After initial testings which showed that the unit was accurate, I invested time to modify the cover of the unit as the airflow through the unit is through a grill and could be increased to have a faster response time. Steps for the modification are given below:
1) The cover is held by 4 small screws. Remove them by a jewelry screw driver.
2) Separate the back cover from the main body gently and not too far apart as there is a ground wire of the battery housing connecting the two.
3) Remove the ground wire from the battery housing. Now the two parts can be separated.
4) There is a plastic stick used for changing deg C to deg F. It will fall out but is easy to put back during re-assembly.
I drilled four 3/16 inch holes on each side of the back cover as well as one 3/16 inch at the center of the back cover.
The above measurements were done on just one AcuRite which I bought. Because measured data points seem to agree with published values by other scientists, I am satisfied that the humidity and temperature of my unit are accurate and use it with confidence. However, beware that there are a large number of reviews in this forum who said their AcuRite is no good.
By benjamin bannister
*** UPDATE ***
I've updated this review now that I've had more experience with this hygrometer and was able to compare it to competitor models.
I own this humidity monitor, and a Boneco/Air-O-Swiss 7135 Ultrasonic Humidifier). Both of them have humidity readers, but they have readings on opposite ends of the spectrum. When my AcuRite says 65%, my Air-O-Swiss says 45%. I like to take an average of the two, and pretend that is the actual humidity.
— ACCURACY —
Recently, I got two other hygrometers from other manufacturers to compare to. I have placed it near the middle of my living room with nothing blocking it on all sides to help with the reading. Based on my readings, I can confidently say the temperature is accurate, and the humidity is within a 1-2% margin of error, which is perfectly acceptable for me. It updates the readings about every ten seconds.
— DESIGN —
The monitor itself is small at 3" H x 2.5" W and runs on one AA battery. The LCD readout is large and easy to read from a short distance. There is a tiny kickstand on the back that is very helpful at standing this at an angle. There is a magnet on the back, but the glue holding it isn't strong and mine fell off from where it was sticking; I leave it on its stand instead.
— SUMMARY —
This is a nice, compact, and accurate hygrometer for all your hygrometer needs. Recommended.
I've updated this review now that I've had more experience with this hygrometer and was able to compare it to competitor models.
I own this humidity monitor, and a Boneco/Air-O-Swiss 7135 Ultrasonic Humidifier). Both of them have humidity readers, but they have readings on opposite ends of the spectrum. When my AcuRite says 65%, my Air-O-Swiss says 45%. I like to take an average of the two, and pretend that is the actual humidity.
— ACCURACY —
Recently, I got two other hygrometers from other manufacturers to compare to. I have placed it near the middle of my living room with nothing blocking it on all sides to help with the reading. Based on my readings, I can confidently say the temperature is accurate, and the humidity is within a 1-2% margin of error, which is perfectly acceptable for me. It updates the readings about every ten seconds.
— DESIGN —
The monitor itself is small at 3" H x 2.5" W and runs on one AA battery. The LCD readout is large and easy to read from a short distance. There is a tiny kickstand on the back that is very helpful at standing this at an angle. There is a magnet on the back, but the glue holding it isn't strong and mine fell off from where it was sticking; I leave it on its stand instead.
— SUMMARY —
This is a nice, compact, and accurate hygrometer for all your hygrometer needs. Recommended.
No comments:
Post a Comment