Temperature and humidity

Under strict control

From 260 PLN! Go to Store

Efento Logger is a wireless temperature and humidity logger communicating with smartphones and tablets via Bluetooth 4.0. The logger saves in its memory up to 28 000 measurements that can be later wirelessly transferred to a phone or tablet. Efento Loggers are supported by free application for Android devices.

Why Efento Logger?

  • Easy operation

    You don’t need any computers, drivers, cables

  • High memory capacity

    Saving up to 28 000 measurements

  • Ease of use

    Long range and long service life of wireless loggers

  • Registration of  temperature and humidity

    Take care of works of art and other exhibits

Efento Logger functions together with smartphones and tablets

By using wireless communication technology to transmit data, it is possible to read the data from the recorder/logger without physical access to the device – you can forget about pulling the logger from the cabinet or container and connecting it to your computer!

Efento Loggers record temperature and humidity levels, which is very essential for storing and displaying works of art sensitive to changes in these parameters.

The solution is perfect for monitoring environmental conditions in display cabinets in museums, without having to take the loggers out to transfer the measurements. You should only approach with your mobile device to a logger, and the data will be transferred to the phone or tablet. One device can support unlimited number of the loggers – simply select the desired one from the list on the screen.

The most convenient to use temperature and humidity logger

You can forget about a computer, drivers, cables!

Watch the video tutorial and see how easy it is

Temperature and humidity in museums

The range of temperature and relative humidity should be adapted to the type of exhibits and the material they are made from. Specific values of relative humidity and temperature recommended for storing works of art made from different materials are specified e.g. in the study „Determining the Acceptable Ranges of Relative Humidity And Temperature in Museums and Galleries” – Smithsonian Institution.


General recommendations on temperature and humidity levels in indoor environments of museums, galleries, storage areas, archives, libraries etc.:

  • Temperature within 19–21°C is the best compromise between comfort of visitors and the expenditure for energy consumption. If the room temperature does not change rapidly, it has little effect on the condition of works of art.
  • The optimum relative humidity for mixed collections is 45–55%. Too high relative humidity (over 65%) can cause the growth of mold and fungi on paintings, metal corrosion or damage to library collections. On the other hand, too low relative humidity (below 25%) leads to the loss of hygroscopic water – fragility of materials like leather or paper, and an increase of mechanical stress, especially in wood items.

Relative humidity has a much greater impact on the state of museum exhibits than the temperature.

Especially destructive are rapid changes in humidity, seasonal fluctuations are less damaging.

What level of relative humidity of the air is appropriate for museum exhibits?

Proper temperature and relative humidity levels are defined by EN 15757:2012 (Conservation Of Cultural Property – Specifications For Temperature And Relative Humidity To Limit Climate-Induced Mechanical Damage In Organic Hygroscopic Materials).

According to the norm, the relative humidity in the room/cabinet with works of art should be determined on the basis of the so-called historical climate to which the items are acclimated for a longer time. The historical climate, i.e. the range of relative humidity and temperature in which exhibits have been stored without adverse effects, can be determined on the basis of measurements conducted for at least 12 months. Analyzing the historical climate, one should take into account seasonal changes in humidity, e.g. due to heating period.

Historical climate is described by three parameters:

  • Average value of relative humiditythe arithmetic mean of all measurements (the sum of all relative humidity measurements divided by the number of measurements). The measurements should come from the whole year. To determine seasonal changes, it is necessary to calculate the average value for each month.
  • Centered moving averagemoving average of 30 days (for the average for a given day, one takes into account measurements from two weeks before and two weeks ahead of the day)
  • Short-term fluctuations – differences between day measurements and corresponding centered moving averages calculated for these days.

The  values obtained from the above calculations describe the historical climate to which the exhibits have been acclimatized. Such conditions should be continued in the room / cabinet intended for storing the objects. What’s more, if the fluctuations in relative humidity have been significant, they should be minimized. The norm specifies that any fluctuations beyond the [-1.5, 1.5] range of standard deviation have to be eliminated.