Fractional BAS Buying Checklist
A structured checklist for evaluating fractional building automation systems before you sign a contract. Use it to define your requirements, compare systems on equal footing, vet vendors, and avoid the agreement terms that create long-term problems.
How to Use This Checklist
This checklist is organized into four phases that correspond to a typical procurement process: defining your requirements before you talk to vendors, evaluating the system itself, evaluating the vendor organization, and reviewing the contract terms. Work through the phases in order. Skipping to vendor demos before completing Phase 1 is the most common mistake buyers make, and it puts vendors in control of the conversation from the start.
Each item in this checklist is framed as a question or decision point rather than a simple yes/no checkbox. That framing is intentional: the goal is not to collect checkmarks, but to surface information that distinguishes a system that will serve your building from one that will create recurring problems.
What Requirements Should You Define Before Talking to Vendors?
Complete this phase before your first vendor conversation. The answers will determine which systems are worth evaluating and which questions to ask. Bring these answers to every vendor meeting.
What parameters does your building need to measure?
Common parameters include temperature, relative humidity, CO2, and total volatile organic compounds (TVOCs). You may also want to measure carbon monoxide, barometric pressure, light levels, and particulate matter (PM2.5). Not all systems measure all parameters. List the specific parameters your use case requires, and separate must-haves from nice-to-haves. A system that measures 12 parameters but misses the one your tenant’s lease requires is not fit for purpose.
How many sensors do you need, and where must they go?
Count the distinct zones, rooms, or points you need to monitor. Identify any locations with challenging conditions: high ceilings, exterior walls, kitchen adjacency, or spaces with heavy foot traffic. Confirm whether the vendor’s system can achieve adequate coverage in your specific building layout before you request a quote.
What does success look like at 12 months?
Define a concrete, measurable outcome: a specific reduction in energy costs, an understanding of environmental impacts on production that you can act on, elimination of comfort complaints in a particular zone, documentation that satisfies an insurer or regulator, or a report your property manager can use in tenant conversations. A clear definition lets you evaluate whether any given system can realistically deliver it, and gives you a baseline for measuring vendor performance after deployment.
Who will use the data, and how often?
Identify the actual user: a building owner who reviews a monthly PDF report, a facilities manager who checks a dashboard several times per week, or a property management company that needs data in a format compatible with their existing tools. The right system is the one that delivers data to the person who will act on it, in the format they will use. A system with sophisticated analytics that no one checks is not better than a simpler one that actually gets read regularly.
What is your total budget, including ongoing costs?
Hardware and installation are the visible costs, but ongoing subscription fees, cellular data charges, calibration, and eventual hardware replacement can exceed upfront costs over a three-to-five year horizon. Establish your total budget for year one and for years two through five before comparing quotes. See the BAS cost breakdown guide for a detailed framework.
How Do You Evaluate the System?
Use these criteria to assess the technical fit of any system you are seriously considering. Request documentation or live demonstration for each item. Vendor claims without supporting evidence should be treated as unverified.
| Criterion | What to Ask or Verify | Why It Matters |
|---|---|---|
| Parameter coverage | Does the system measure every parameter on your must-have list? Are sensor accuracy specs documented? Have they been tested rigorously? Do they reference a recognized standard (ASHRAE, EPA)? | A system missing a required parameter cannot be remediated by configuration. Accuracy specs without external validation are not meaningful. |
| Sensor density and placement | How does the vendor approach planning sensor layouts? How many sensors do they recommend for your square footage? Can they provide a coverage plan specific to your floor plan? | A system installed with too few sensors for your layout will produce zone averages that miss localized problems. |
| Connectivity and infrastructure | What network does the system use: WiFi, cellular, Bluetooth mesh, LoRa, or proprietary RF? Does installation require running new cable or modifying existing infrastructure? | Connectivity determines installation cost, ongoing reliability, and whether deployment is feasible in your building without significant construction. |
| Data access and portability | Can you export raw data in a standard format (CSV, JSON, API)? Can you access historical data if you decide to cancel service? | Data lock-in is a significant switching cost. If the vendor controls your historical data, you are dependent on them for continuity even when service is poor. |
| Reporting and alerts | What reports does the system generate automatically? Do they contain just data, or do they contain actionable insights? Are alert thresholds configurable per zone? Who receives alerts, and how (email, SMS, dashboard)? | You probably don’t have time to be a Data Scientist. Reports that match your actual use case and provide actionable insights save significant time. Alert systems that cannot be configured to your thresholds generate noise instead of signal. |
| Dashboard and user interface | Request a live demo using real data, not a marketing slide. Who accesses the dashboard, and does it require training? | A dashboard your team will not use daily is not better than no dashboard. Complexity that does not serve your use case is a liability, not a feature. |
| Integration capability | Can the system integrate with your existing HVAC controls or BMS? Does it support BACnet, Modbus, or API connections to third-party platforms? | Integration determines whether monitoring data can drive automated responses or must be acted on manually. Relevant only if you have existing controls infrastructure, or plan on upgrading sometime soon. |
| Calibration and maintenance | How often do sensors require recalibration? Is calibration performed by the vendor, by the building, or automatically? What is the process and cost? | Sensors that drift out of calibration produce inaccurate data. If recalibration is manual and not included in the service contract, accuracy degrades over time. |
How Do You Evaluate the Vendor Organization?
The system and the company that supports it are not the same thing. A technically sound product from an organization with poor support, unstable financing, or a history of abandoned deployments is a poor procurement decision. Use these criteria to assess the vendor organization, not just the hardware.
Track record and references
Ask if the vendor can provide two or three reference customers, ideally in buildings similar to yours in size, use type, and age. Contact them directly, not through the vendor. Ask specifically about installation experience, the accuracy and reliability of data after the first 90 days, and how the vendor responded when something went wrong. If a vendor cannot provide references, or if they insist on routing all reference conversations through their own team, be sure to ask why.
Support model and response time
Clearly establish who your point of contact is, what the expected response time is for support tickets, and whether support is handled by the vendor directly or outsourced. Ask what happens if a sensor fails: who initiates the replacement, what is the timeline, and is there a cost? You want to know exactly what you’re in for if something goes wrong.
Business stability
Ask how long the company has been operating and whether it is profitable or venture-funded. Ask specifically what happens to your data and your deployed hardware if the company is acquired or ceases operations. A startup with 18 months of runway is a different risk profile from an established company with a customer base. Neither is automatically disqualifying, but both require honest risk assessment.
Installation process and timeline
Ask for a specific installation plan for your building: who installs (the vendor, a subcontractor, or your facilities staff), how many hours of access are required, whether any spaces need to be vacated, and what the expected downtime is. Vague answers to installation questions indicate the vendor has not assessed your building and is providing a generic estimate.
What Contract Terms Should You Review?
Most disputes between building owners and monitoring vendors arise from contract terms that were not reviewed carefully before signing. Review these items specifically before executing any agreement.
Data access and portability
Confirm in the contract language that you can access the data generated by sensors in your building. Confirm that historical data is exportable in a standard format and that the vendor will provide an export upon request, including upon contract termination.
Term length and exit provisions
Note the minimum contract term and the notice period required to cancel. Ask what happens to installed hardware at the end of the term: does the vendor remove it, does it become your property, or does continued use require a new contract? Multi-year contracts with punitive early termination fees for an unproven system are a significant financial risk.
Service level and uptime commitments
For most building types, monitoring is an important, but not critical, service. If your fire alarm or security system goes offline, you have a significant problem. In contrast, if your monitoring platform goes offline briefly, there may be relatively little immediate impact. Keep this in mind when you think about Service Level Agreements (SLAs). Not all vendors will offer an uptime commitment or formal SLA, and if they do it may add significant cost. For many use cases a formal SLA is probably overkill. But do make sure the vendor provides mechanisms to solve problems if they arise, and some kind of compensation if the problem is severe e.g. the platform is offline for an extended period. Compensation could include a service credit, a refund, or something else. Just make sure it’s spelled out clearly.
Price escalation
Ask whether the subscription price is fixed for the contract term or subject to annual increases. If increases are permitted, confirm whether they are capped (for example, at CPI or a fixed percentage). Uncapped price escalation clauses in multi-year monitoring contracts can significantly change the economics of your deployment relative to the original quote.
What Red Flags Should Pause or Stop a Procurement?
The following are not negotiating points. Each one represents a pattern that consistently produces poor outcomes for building owners.
- Accuracy specs without external validation. Sensor accuracy claims that cite the vendor’s own internal testing only, with no reference to ISO, ASHRAE, or EPA calibration standards, cannot be verified and should not be relied upon for compliance or health applications.
- Data access is ambiguous or vendor-controlled. Any contract language that does not clearly state “customer can access all data” should be reviewed by your attorney before signing. Ambiguous access is not a drafting oversight; it is a business model.
- No written support response commitments. A support model described verbally but not reflected in the contract does not exist when you need it. Verbal assurances from a sales representative are not contractual obligations.
- Hardware removal requires vendor approval or a fee. You installed the hardware in your building. Any clause that restricts your ability to remove or replace it without vendor consent or payment should be treated as a control mechanism, not a routine term.
- Multi-year commitment required before a pilot is possible. A vendor unwilling to offer a limited pilot or proof-of-concept period before a multi-year commitment is asking you to absorb the deployment risk entirely. Established vendors with reliable systems can afford to let the data speak first.
More Buying Guidance
This checklist works alongside the other guides in the buying guidance section. Use them together for a complete evaluation.
How to Choose a Building Monitoring System
A detailed framework for evaluating monitoring systems against six criteria, including questions to ask every vendor during the sales process.
Fractional BAS vs. Full BAS
A head-to-head comparison of fractional and full building automation across cost, complexity, functionality, and building size fit.
BAS Cost Breakdown
A detailed breakdown of what full BAS actually costs, including why labor drives 50 to 75 percent of total project expense and how regional variation affects pricing.
What Is Building Monitoring?
The foundational explainer on what building monitoring systems measure, how spot monitoring differs from continuous monitoring, and where fractional BAS fits in the landscape.
See a Fractional BAS That Checks Every Box
Nosy is a fractional BAS built for commercial buildings under 100,000 square feet. It monitors eight environmental parameters via a wireless mesh network, delivers monthly OSHA-referenced reports, and stores data in your account. No long-term contract required for a pilot.