All too often presence detection is used for lighting and the HVAC benefits are ignored or forgotten.
This is missing a trick and can mean buildings are using more energy than they need to.

Background

Presence detection is often used for lighting, and in the past it was used for HVAC. But in recent years I have seen a decline in the use of presence detection for HVAC control in rooms.

This is unfortunate as it means rooms and spaces are often running in comfort and using energy when unoccupied. This is obviously bad for climate control and at a more basic level means the building operator is paying more for their utility bills.

Using a presence detector (PIR) to detect occupancy and control HVAC ensures that energy consumption is reduced. This is obviously a good scenario and can be applied to many types of buildings including offices and schools.

Why isn’t it done more?

A key challenge is the use of so called “value engineering” on projects which results in functionality being removed to save costs.
Another challenge is ensuring the project specification covers this kind of energy efficient strategy.

What we need to see is more specifications and contractors making these types of solutions core features that cannot be removed and must be adhered to. In many cases the long term benefits to the building energy use are not considered, the short term project costs unfortunately take priority.

Good room control utilises presence detection as well as CO2 and maybe fine dust detection to ensure a comfortable and energy efficient environment.

Practicalities

It is far easier and cheaper to include and implement presence detectors and other options at a construction and fit-out phase.
If we wait until buildings are occupied and in use it becomes more complex and expensive to implement these kinds of solutions.

And it is easy to blame consultants and contractors, but the controls company should also be highlighting the benefits and reasons to implement presence detection.
Even if it is not part of the basic quote it should be highlighted as an option with the long term benefits included.

Where I see things changing is when end users or finance officers see the impact on future building operating costs highlighted. This can help ensure good features are retained maintaining an energy efficient building.

Closing thoughts

Over time as an industry we have accepted a process that results in key elements of systems being removed to make short term cost savings that impact on long term operating costs. We need to move away from this to a model where the long term impact of changes is considered and takes priority.

We also as an industry need to make sure we follow all the best standards when it comes to designing and implementing our systems.
Are we meeting a good level of BS-EN15232, are we really providing an efficient solution base on the eu.bac standard?

And it comes back to one of my previous blogs, we need to stop considering the HVAC, lighting and blind/shading elements of a project separately and deliver integrated efficient buildings.
The reality is that a presence detector (PIR) that is used for HVAC, lights and blinds is a far more cost effective solution than considering separate systems.

For more of my thoughts and opinions on integrated buildings and standards that ensure energy efficient and comfortable operation see my previous blog articles…
https://ingenuity.siemens.com/2019/05/what-is-an-integrated-room-and-why-should-i-consider-them-in-my-building/

https://ingenuity.siemens.com/2019/08/energy-efficiency-standards/