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BMS vs. EMS vs. BAS vs. ClevAir – What’s best for your building?

The abbreviations BMS, EMS, and BAS are often used interchangeably. Even though there is some overlap in functionalities, each offers value in different ways.

Then there’s ClevAir; a smart building solution that doesn’t exactly fit in any of the aforementioned categories, but does offer some unique features.

In the following article, we will compare these four smart building systems, and help you choose the right one for your property.


  1. What is BMS and its features
  2. What is BAS and its features
  3. What is EMS and its features
  4. What is ClevAir and its features
  5. Features comparison – quick overview 
  6. How to chose right solution

BMS meaning: What is BMS?

BMS meaning and its features

A BMS, short for building management system, is an all-inclusive control system to manage buildings. Typically installed in large buildings, a BMS is the most expensive of the 4 smart building solutions discussed here.

A modern BMS is able to control, monitor, and maintain most, if not all of a building’s systems, like fire, ventilation, lighting, security, power, water, sewerage, and energy etc. A BMS comprises many small-and-large, software and hardware components, e.g., controllers, sensors, output devices, communication protocols, and interfaces. Thus, its full installation can sometimes take several months to complete. 

What features does a BMS have?

Building management systems have a wide-ranging set of features, including, but not limited to:

  • Define setpoints for HVAC at any time.
  • Control the security of a premises from the central console.
  • Adjust, control, and monitor the lighting within a building.
  • Monitor different systems and appliances, and raise necessary alarms if a fault is detected.
  • In some buildings, a BMS is also responsible for controlling the air handlers. E.g., in chemical factories and oil refineries, a BMS monitors and optimizes air flow to ensure the safety of workers.

What is a BAS?

What is BAS building automation system

A BAS, or building automation system, is another intelligent product that simplifies building management. However, it’s a much smaller solution, with a lot less features. It can be argued that it’s a subset of a BMS.

The terms BAS and BMS are often used interchangeably. Depending on which country you are in, or what company you talk to, you may get completely different definitions of the two. In reality, a BAS offers limited functionalities, but does often include smarter analytics and more automated controls. 

What features does a BAS have?

A BAS can:

  • Quickly and automatically adjust the settings of different mechanical and electrical systems (e.g., HVAC, lighting, air control) within a building, based on sensor fluctuations.
  • Automate the most mundane maintenance and operational activities. 
  • Provide remote controls to various building systems and appliances, from a central hub. E.g.Lock the entire premises down with the push of a button, decrease ventilation settings without touching the HVAC, or turn all lights on with one switch. 

What is an EMS?

What is EMS energy management system

EMS, an abbreviation for energy management system, is a smart tool used to monitor energy utilization within a building. An EMS can collect energy data from various appliances and systems within a solution, and (sometimes) identify avenues of optimization. E.g., it may suggest configuring certain setpoints for a HVAC solution, at various times of the day.

Installing an EMS may require adding sensors to various systems to a building that report real-time data to a central controller.

What features does an EMS have?

A non-exhaustive list of an EMS’ features is:

  • Get real-time insights into a building’s energy usage. Which appliance is overconsuming energy, and which is the most energy-efficient?
  • Get suggestions regarding energy optimization.
  • Benchmark energy usage and compare with high-performing buildings from the industry/region.
  • Forecast energy usage and plan budgets accordingly.

Where does ClevAir fit in?

Building management with ClevAir

ClevAir is a smart building product that optimizes energy usage, automates operations, gives an overview and reduces costs in addition to CO2. It doesn’t fall into any of the categories we covered above, but it does have a fairly diverse feature-set. 

It automates HVAC operations, like some BAS do; it helps you monitor and track energy usage, like a traditional EMS (but goes beyond that by automatically optimizing energy use), and lets you remotely monitor and control some parts of your building(s), much like a modern BMS.

Another feature that sets ClevAir apart from traditional solutions, is that it usually doesn’t require any significant hardware upgrades for installation. It’s also remarkably interoperable; can seamlessly integrate with different existing building systems. 

What features does ClevAir have?

In addition to the aforementioned, ClevAir also offers the following features:

  • Provides portfolio-wide insights regarding energy usage and carbon emissions.
  • Optimize HVAC in real-time, based on several fluctuating factors like occupancy, indoor and outdoor weather, and CO2 levels in the building. This ensures a stable indoor climate and optimizes energy usage.
  • Ability to remotely monitor and control climate settings, as well as energy and CO2 levels of all the buildings in your portfolio.
  • ClevAir shows cut back on energy costs by 15-25%.
  • Suitable for commercial buildings of different types: from office buildings and shopping malls, to warehouses, and fitness centers. ClevAir can be installed in building with or without BMS.

Read more about ClevAir’s features

BMS vs. BAS vs. EMS vs. ClevAir – overview

BMS vs. BAS vs. EMS vs. ClevAir - a features comparison
A features comparison summary of BMS vs. BAS vs. EMS vs. ClevAir

Which Solution to choose for your building?

What system you choose depends on your building size, budget, and expectations.

Go with a BMS if you:

  • If you have a large (>10,000 square foot), newly-constructed building, and budget is not a concern.
  • If you want to automate and control virtually every aspect of your building.
  • If you are okay with waiting for a long installation process to complete. 

Go with a BAS if you:

  • If you only want to automate and control some of the most important mechanical and electrical systems of a building.
  • If you can’t afford a BMS, but still want to automate various things in your building.

Go with an EMS if you:

  • Only want to monitor energy usage for a building, and can implement suggested optimizations yourself.
  • Want to benchmark your building.

Go with ClevAir if you:

  • Want to automate your HVAC system, such that it optimizes energy usage and indoor climate in real time, based on changes in the weather, room occupancy, and CO2 levels.
  • Want to have remote control over your buildings’ HVAC settings.
  • Don’t want to replace or install a lot of new hardware.
  • Have a smaller building, where it doesn’t make sense to install an expensive BMS. Or you simply don’t have the budget to afford a BMS.
  • Want to use a cloud-based dashboard to monitor the energy usage of your entire portfolio.
  • Want to improve indoor air quality.

If you have any questions about ClevAir, just give as a call or send us a message:

Final Word

As we saw in the article, the smart building solution you choose depends on your budget, size and type of building, and preferred level of automation and optimization. Still not sure what’s right for your building? Read what people had to say after optimizing their buildings with ClevAir:


We are pleased with the results. Clevair has created an ecosystem where new and old technology can interact, giving new life to older technology. For us, it means increased service life of our technical installations, reduced energy consumption and in many cases, a better user experience.

This is sustainability in practice


Thomas Thorstensen,
Technical Manager at Selvaag Eiendom
Gisle Bryne, Business Development Manager at ACsenteret

We installed ClevAir to save energy, and they sure have delivered.


However, what we didn’t know and what turned out to be the biggest benefit is the improvement of our indoor climate.


Gisle Bryne,
Business Development Manager at ACsenteret

To learn more about how ClevAir works its magic, and see what kind of results it can produce



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