Vet Your IAQ Monitoring Vendor: 3 Essential Questions

Evaluating an indoor air quality (IAQ) monitoring vendor means looking far beyond sensor tech specs. The right vendor is one who thoroughly understands the mechanical systems that control your building (the HVAC architecture, communication protocols, zone structure) and can deploy, calibrate, and integrate a monitoring solution around that reality. The wrong one will hand over the data and leave the rest to you.

Any vendor can explain their sensor specs, and most buyers will only focus on the obvious criteria (parameters measured, installation type, connectivity), check those boxes, and move forward.

What often gets missed is whether the vendor actually understands how buildings operate. Those gaps may not show up during procurement, but they almost always surface later - during deployment, troubleshooting, or certification reviews - when they're much harder and more expensive to fix.

Having walked countless projects through this decision-making process, these are the three questions that help you instantly differentiate between a vendor who simply sells sensors in a white box and one who truly understands the built environment.

Question #1: How Does Your Automation Actually Work?

IAQ monitoring is only useful if it can drive an action or response, like adjusting ventilation, triggering a damper, or flagging HVAC issues for maintenance. To do that, the sensor output has to connect to the systems that actually control your building: a local controller, a building management system (BMS), or both, using a specific communication protocol.

Green Flag Answers

A vendor with real mechanical expertise should be able to explain the difference between a fan coil unit (FCU), a VAV box, and an air handling unit (AHU) without hesitating, and name the specific types of equipment their system can control. Beyond that, they should be able to walk you through the full integration picture:

• Output type: analog or digital
• Connection path: direct to a controller, or routed through the BMS
• Control logic: runs locally on the device, or depends on cloud connectivity
• Protocols supported: BACnet, Modbus, or proprietary

Red Flag Answers

Vague answers, like references to “actionable insights" without any specifics on how those insights reach your mechanical systems, suggest the vendor understands sensors, but not buildings. Without that mechanical knowledge, you end up with data that identifies a problem but no direct path to address it. The integration work and the cost of figuring it out will inevitably fall on your team.

Question #2: How Do you Handle Calibration?

The sensor accuracy spec is not a lifetime guarantee of accuracy. Sensors, like any physical component, go through wear and tear and will drift over time (particulate matter sensors especially), making regular calibrations crucial. If you plan to use your data to optimize ventilation, support certification compliance (WELL, LEED, RESET, etc.), or improve occupant health, the reliability of that data depends entirely on whether the vendor has a sound calibration process.

Green Flag Answers

Calibration is a comparison against a known reference standard. A vendor who understands the physics of their device should be able to tell you what physical reference they calibrate against, how the field calibration process works in practice, and how often recalibration is required to maintain accuracy.

Beyond the process itself, look for:

• Serviceable or replaceable sensing elements, meaning the hardware was designed with long-term use in mind
• A clearly documented calibration and servicing program, with a defined schedule and transparent costs
• Acknowledgment that sensors wear over time, because they do, and vendors who are upfront about it have usually supported deployments long enough to know this firsthand
• Specifications about drift rates, and honest information about the conditions that accelerate them

Red Flag Answers

If the vendor talks about "auto-calibration" or "calibrating from the cloud," ask what reference they’re actually calibrating against. Without a physical reference standard, there can be no calibration. Cloud-based correction may be able to account for relative drift, but it cannot replace comparison against a known standard.

If a vendor can't explain their calibration methodology in concrete terms, the accuracy of the data you'll be relying on remains an open question.

Question #3: How Do You Decide Where to Deploy Sensors?

Where a sensor is placed determines what it can actually measure. The air inside a building is not uniform; it’s divided into zones by the HVAC system, each served by its own equipment. Mapping sensors without accounting for that zone structure, as well as how different spaces are actually used, will lead to inaccurate data - some areas over-represented, others not measured at all.

Green Flag Answers

Sensor deployment should be driven by the mechanical architecture of the building:

• How HVAC zones are laid out
• Which space(s) each air handling unit serves
• How VAV boxes are distributed
• Where occupied and high-traffic spaces are located

The right vendor will want to review mechanical drawings before finalizing a deployment plan. The goal is one sensor per HVAC zone (or sometimes more, depending on conditions), not one sensor per X square feet. Vendors working on building certification projects should also be familiar with the placement requirements of the targeted certification and factor those into their recommendations from the start.

Red Flag Answers

If the vendor references a square footage rule of thumb, such as one sensor per 1,000 sq ft, or one per floor, that's a sign the deployment plan is being driven by a formula rather than the building itself.

Two adjacent rooms on the same floor can behave completely differently depending on airflow, occupancy, and return-air configuration. A mapping strategy built around square footage can look complete on a floor plan but still leave major gaps in coverage.

It's possible to end up with three sensors in one HVAC zone and none in the one next to it, and the data alone won't surface that problem. Those gaps tend to show up later, in occupant complaints or a certification compliance review, at which point correcting the placement adds significant costs and disruptions that could have been avoided with the right planning upfront.

What These Answers Mean for Your Vendor Evaluation

These questions don't require technical expertise to ask, but the answers will tell you a lot about the depth of expertise on the other side of the table. A vendor's spec sheet can list protocols, certifications, and integrations, but it won't tell you whether the person deploying your system understands how your building actually operates.

Look for answers that are specific, consistent, and grounded in mechanical reality. Vendors who can answer all three clearly are the ones who have worked through the challenges of real-world deployments before, and can help you avoid the issues that become expensive and disruptive to fix later.

Recap: 3 Questions to Vet Vendors on Built Environment Expertise

Looking for a more comprehensive breakdown on how to evaluate commercial IAQ monitors? Read our complete guide covering sensor types, certifications, integration considerations, and deployment planning.

Work With a Team That Understands Buildings, Not Just Sensors

At Kaiterra, our team brings deep expertise in IAQ, mechanical systems, and the built environment, and we work alongside our clients from start to finish. That means going beyond simply mapping sensor locations to a floor plan. We help design deployments around HVAC architecture, support troubleshooting when something doesn't look right, and help teams make sense of their data once it's flowing.

It's a consultative process by design, because the questions in this article are exactly the ones we've seen go unanswered in projects that later ran into problems.

Scoping an IAQ project? Reach out to our team to talk through what the right deployment looks like for your building.