Environmental Data Logger Buying Considerations For Collections Care

by | Sep 19, 2023 | Blog

So you’re ready to upgrade from your ancient hygrothermograph or your manual spot checkers for temperature and humidity to a modern environmental data logger. But what should you buy? Except for the Image Permanence Institute’s PEM2s and, more recently, Conserv, the heritage world has rarely had field-specific products made for it. This means that there have been a myriad of choices you can buy taken from other industries including health, food, environment sciences, among others. Traditionally, collections care professionals have found their favorite brands and models and stuck to those.

So with so many choices, where do you even begin to look at the market? In this post, we will discuss some of the most important considerations you should take into account and provide some tips on how to choose the best environmental data logger for your specific situation.

Sensor specifications

The main purpose of your environmental data logger is to give you the kind of data you require to make decisions that will impact the quality of your collections care. So the most important things you need to look at are accuracy and resolution.

Accuracy is the degree to which a measurement reflects the true value of the parameter being measured. Resolution is the smallest change in the parameter that can be detected by the device. Together, they will determine how reliable and precise the data is. You should decide what are acceptable levels of accuracy and resolution for your particular purpose as they will depend on several factors that will affect the cost of your environmental data logger: for example, quality of the sensors inside, calibration processes and the environment you intend to place the logger in.

Remember that different parameters in your data logger may have different levels of accuracy and resolution based on the sensors inside the device. For example, temperature may be more accurate and precise than relative humidity or light. Make your choices depending on what your most important parameters are for each space and how much accuracy you need.

Calibration costs over time

Remember that environmental monitoring is not a one-time cost. Calibration is key and should be an essential part of your equipment maintenance routine. If you seek accuracy in your readings, calibration is necessary because sensors can drift or become less accurate over time due to factors such as wear and tear, exposure to varying environmental conditions, or the natural aging of the instrument. Understanding the degree of deviation and making necessary adjustments to your equipment will enable you to make more informed and effective decisions. Always factor in the cost of your calibration services as an additional expense – and remember calibration costs are per sensor!

Look for:

  • High-quality sensors that are suitable for your collections care environment.
  • A calibration certificate or statement showing when and how the device was calibrated.
  • A calibration interval that matches your collections care standards.
  • A calibration service that is available in your region and affordable.

Budget and staff time

The time your staff needs to take to collect and analyze the data from your environmental data loggers is a hidden cost of environmental monitoring that can be easily forgotten.

If you buy data loggers on the cheaper side, you could be engaging in a false economy. Let’s say it takes, on average, 2 hours per data logger to collect, download, reset, analyze information, and put the device back in its place. So while you may have saved a hundred dollars on each device, you are actually losing out on the hourly wage of your staff every time data needs to be collected – which can be once a quarter or as often as once a month for some institutions.

Let’s say your data is collected and analyzed by volunteers who do not receive payment. Just because they are volunteering their time for you does not mean their time has no actual dollar value, so is there something more valuable that they could be doing at your organization? Try adding a benchmark minimum wage for their hours and do some quick back of the napkin calculations. How is your collection benefiting from their donated time? Are you using up your precious volunteer time on tasks that bring back less value than they cost? You might end up being surprised!

Connectivity type

The type of connectivity for your environmental data loggers will have a direct impact on two things: how much time it can take your humans to collect the data and how many devices you need to purchase. For example:

  • Your loggers require a USB or nearby Bluetooth connection to download. This means your staff has to collect all the loggers, download the information to a PC and then place the loggers back, or walk around with a cable and laptop, or a BT-enabled phone every time data needs to be gathered.
  • Your loggers work with WiFi or Bluetooth and upload information in real-time.  It’s important to note that loggers typically require an unobstructed range of 100-700 ft to establish a connection and upload data to the gateway. This means that no physical barriers, such as walls, steel structures, or even tall furniture, should obstruct the line of sight between your logger and the area you are monitoring. Remember that storage shelves and fire doors are often tall and made of metal, which can potentially interfere with the signal transmission. . Additionally, your gateway probably needs a wired LAN connection to a computer or a wall outlet before it can establish a connection with your data loggers. (like when you plug in the little cable to your computer to get internet straight from the wall instead of WiFi).
  • Your loggers have LoRaWAN and upload data in real-time. Your gateway can connect to the with a wired LAN connection and/or use an internal SIM with data like a phone plan. The environmental data loggers then connect to the gateway through LoRaWAN (which is neither WiFi nor Bluetooth). LoRaWAN connections allow sensors to see gateways across very large distances, through walls and even across different floors on a building so you need fewer gateways.

We recommend that you look for environmental data loggers that have:

  • A reliable connection type that suits your collections care environment and building fabric and design.
  • A compatible connection format that works with your existing devices and systems.

IPM and freezer capabilities

If you intend to have your data loggers in regular storage spaces, you probably don’t need to worry about this point. However, if you are carrying out integrated pest management at your organization and require data loggers to go into freezers at -22°F (-30°C) for your treatments, make sure you buy data loggers that can withstand these temperatures and still remain accurate. This will also need to be a consideration if you have cold storage for delicate archival materials (like early plastics, photographs and negatives). Ideally, this special data logger will merge seamlessly with the rest of your equipment so you don’t have to juggle various pieces of software.



Software analytics

Software is the program or application that allows you to configure, control, download, analyze, and report the data collected by the device. The most famous one for use in the heritage field is eClimate Notebook, but it is by no means mandatory. Almost any environmental data logger you can buy these days, whether simple USB versions or modern wireless sensors will come with a free download of the manufacturer’s software.

Depending on the brand, you will get a free, limited software or a more advanced software package that requires a subscription to use. Although different brands used to have proprietary files for their data, most of them will now let you upload your own .csv files – although this is a manual task you will have to spend your valuable time on.

Many modern software solutions for environmental data collection recognize the importance of notifying you with real-time alerts when your data loggers detect unusual spikes or changes. You should note that the simpler USB-download data loggers will not have this capability so that the data you get will always be in the past and dependent on when you download your information, which will limit your capacity to respond quickly to concerning changes in the environment increasing the risk of damage of certain materials.

We recommend that you look for software that has:

  • A user-friendly software interface that is easy to install and operate.
  • A comprehensive software functionality that meets your collections care needs. More on this below.
  • A secure software system that protects your data from unauthorized access or loss.
  • Reliable customer support when things go wrong.

Battery life (and sensor life!)

The battery life of your environmental data logger will depend on several factors such as the sampling rate you set, the type of connectivity it uses to upload data, whether your logger has lights or a screen, and the type of battery. Some devices will have rechargeable batteries that you need to plug in every now and then, while others may use disposable batteries that need to be replaced. Remember that any data logger with a display screen or indicator lights of any sort will be using up battery life to keep those features working.

In addition to this, your data logger itself may have a finite working life. In some cases, the loggers cannot even be recalibrated and will need to be thrown away when the readings stop being accurate.

Regarding battery and sensor life, we recommend:

  • Adjusting your sampling rate to match your collections care needs and maximize battery life. You may read this research paper on sampling frequency.
  • Low power consumption to minimize battery drain.
  • A long-lasting battery type that is easy to replace or recharge.
  • A battery indicator that warns you when the battery is low whether on the device or the software.
  • Being aware of your device warranty. How long will it cover you? How reliable is the device you are buying? What do customer support reviews say when things don’t work? How likely are you to get a replacement if something does go wrong?
  • Being aware of the sustainability of your data loggers over time. Do you know what happens to their components at the end of their useful life? How polluting are they? Will you know what to do with them when at the end? Check out our Small Collections Monitoring Program where we take in old customer’s devices, refurbish them and give them out for CAP assessments.

Sharing capabilities

Environmental monitoring in a heritage setting is a team effort. You might have people from facilities, operations, IT, collections care, exhibitions, management, and even people outside your organization who will want to see what’s going on in your spaces (think about officers from grant applications, loan officers from other collecting institutions, insurance and fine art transport agents, or even external consultants analyzing your data).

Remember that sharing PDFs over email is not really cyber secure unless you take additional steps. Consider your needs and think about how often you need several people to access your environmental monitoring data. If it’s more often than you’d thought, you might want to consider software that allows you to share this information safely. Different cloud softwares will tell you how many users you are allowed to have and some will charge you per user.

If your information is not sensitive and you are not worried about emailing PDFs, some softwares will allow you to create easy PDF reports for sharing that summarize the most important data so you can take action. Having automatic reports will save your staff the time it takes to manually create them in Excel and will also eliminate the possibility of introducing mistakes during copy-paste operations.

Appearance and personalization

There are four main aspects to appearance and personalization that might affect your environmental data logger buying choice:

  • Size: If you are in a storage space, this is probably irrelevant. You can have any sized logger you want. However, if your data logger will be placed in an exhibition space, you will probably want it to be small and unobtrusive. The last thing you want is an attractive data logger that distracts people from your actual objects on display or, even worse, tempts people to touch it.
  • Color: This is also irrelevant in storage spaces, but you might be interested in data loggers that will blend easily with your exhibition colors.
  • Display screen: Some care professionals prefer loggers with display screens so they can walk around a space and see the numbers on the screen. However, don’t forget that your display screen is draining away battery life. If you have a modern sensor with real-time upload capabilities, you will be able to see the numbers on your phone app from anywhere at all, which makes the screen redundant. If you argue that you’d notice a strange number immediately if you see it on the screen, remember that you can set up alerts on many software applications so that you would get notifications about strange conditions without needing to walk by your sensors to notice them. If you still prefer the screen, note that, in 2023, this is probably more of a “nice-to-have” than a “must-have” feature on a data logger – unless of course you have a manual download logger instead of a real-time upload one. In that particular case, yes, you might like to have that screen.
  • Attachment type: Some loggers are so heavy that the only way to put them somewhere is on a plinth. Others will allow you to either screw them into a wall or slotted shelf brackets, or have magnets to attach them to metal structures.

Conserv’s environmental monitoring platform

Conserv has spent many years talking to thousands of collections professionals to make sure that the product we offer is perfectly designed to help you at both the hardware and software levels. We will quickly address all the points above so you can get an executive summary idea of what Conserv environmental data loggers can offer you.

  • Sensor specifications: Our specifications will vary by the type of sensor you get, but you can be sure that they will fit any expected uses in the collections care world. As opposed to most of our competitors, you will not be using data loggers that have been designed for other industries and made to work in heritage settings. Our data loggers have been designed for you.
  • Calibration costs: As part of your subscription, Conserv will replace sensors that need to be re-calibrated and we will refurbish the old devices so that they don’t end up in a landfill.
  • Budget and staff time: Since Conserv data loggers automatically upload data to the cloud, your staff will never need to go around downloading data again.
  • IPM and freezer capabilities: Yes, we have a dedicated freezer sensor and our software includes IPM monitoring and analyzing capabilities.
  • Software: Don’t be afraid to try the platform for free. You can even import your .csv files from other data loggers. There is no trial period or credit card required to test it. You can just use it! We also have mobile apps for Android and iPhone if you want to try them too.
  • Battery and sensor life: We are committed to replacing your data loggers every three years so you are never working with outdated hardware. Thanks to LoRaWAN, your batteries are unlikely to expire before this date, so you will never have to replace batteries again yourself.
  • Sharing: You may add unlimited users to your Conserv Cloud account at no extra charge.
  • Appearance and personalization: Conserv environmental data loggers are white, but you can purchase covers in any color or even print your own 3D covers as we provide you with the file to do it!


Environmental data loggers are valuable tools for the environmental management of collection spaces.  However, choosing the right environmental data logger can be challenging due to the many factors to consider. We hope that by following the tips in this post, you can make an informed decision and select the best environmental data logger for your collections care needs.

If you have any questions about environmental monitoring, integrated pest management, or just want to talk about preventative conservation, please reach out to us! Don’t forget to check out our blog or join our community of collections care professionals where you can discuss hot topics, connect with other conservators or even take a course to get familiar with the Conserv platform.

Recent posts