ROI — per vertical

This page is the back-of-envelope ROI calculation for each vertical, at Solo tier pricing (€29 / month / site = €348 / year, plus one-time hardware ~€100–€300 for the first three sensors).

The numbers are intentionally conservative: we use the lower end of each saving and the upper end of each cost. If our defaults work out for you, your real ROI is better than what is below.

HACCP / cold chain

Quantified savings (per site, per year)

• Manual logbook time. A staff member writes the fridge temperature in a paper log twice a day. 5 min per round × 2 rounds × 365 days = 60 hours / year. At €12 / hour (Slovak waitstaff rate including social) = €720 / year.
• One avoided spoilage event. A failed fridge over a weekend means ~€300–€1500 of discarded food at a small café. OpenSense catches it ~6 hours after the failure starts. Assume €600 / year averaged.
• Inspector compliance buffer. A ŠVPS fine for missing or inconsistent logs is €332–€3320 in Slovakia (food law sanctions). One avoided event over the product's first year: €332 / year amortised.

Total realised savings: ~€1650 / year, conservatively. Cost: €348 / year + ~€100 sensors. Payback: 3.3 months.

Where it does not pay back

• If the operator was already running OpenSense's competitor with the same logbook-time savings. (Marginal savings: hardware-agnosticism + data export, not the logging itself.)
• If the operator has fewer than 1 fridge and no auditor visit (rare).

Legionella

Quantified savings (per building, per year)

• Reduced sample frequency. A building demonstrating 50/60/50 continuously can move from monthly lab swabs to annual. Swab cost ~€60 each, × 12 saved per year = €720 / year.
• One avoided incident. A Legionella outbreak in a small hotel costs an order of magnitude more than the SaaS — but probability is low. Insurance defends; OpenSense's continuous temperature log is the evidence insurers and lawyers look for. We do not put a number on this; it is real and we do not need to inflate it.
• Faster diagnosis when something breaks. A failed recirc pump with no monitoring takes weeks to notice; with monitoring, hours. Plumber call-out savings: €200 / year amortised.

Total realised savings: ~€920 / year minimum, much more if a near-miss is prevented. Cost: €348 / year + ~€250 in probes and clamp-on PT100s. Payback: 8 months.

Where it does not pay back

• Single-occupant houses (Legionella risk is low; the regulation does not apply).
• Buildings already on a manual quarterly inspection regime they will not relax (some risk-averse health authorities).

Server room

Quantified savings (per server room, per year)

• One avoided AC failure during business hours. Detected within 10 min instead of 4 hours when an employee notices. Avoided hardware damage (one cooked switch): €800 / year amortised.
• Insurance premium reduction. Some EU SMB property insurers give 3–5 % discount with environmental-monitoring evidence. On a €4000 premium that is €120–€200 / year.
• Audit time saved. MSP customer-audit pack now includes the uptime PDF, removing one half-day of spreadsheet construction per customer per year. At 3 customers × €200 / half-day saved: €600 / year.

Total realised savings: ~€1500 / year for the MSP, ~€800 / year for single-rack SMB. Cost: €348 / year + ~€60 (Shelly H&T pair + flood sensor). Payback: 3 months.

Indoor climate — schools

Quantified savings (per school building, per year)

• CO₂ as a ventilation tracer. When monitored, classrooms hit <1000 ppm reliably; absenteeism drops measurably (1–3 % across meta-analyses). For a school of 200 pupils at ~€8 / day cost-per- absent-day on the public budget, 1 % absenteeism reduction is €2920 / year.
• Avoided "we don't ventilate because it's cold" arguments. When CO₂ is visible on a wall display, behaviour shifts on its own.
• Quality argument for parents. Soft savings; we do not count.

Total realised savings: school value is genuinely high but soft-quantified; ROI is policy-driven, not direct. Cost: €348 / year + ~€150 per classroom for a Sensirion SCD41 + ESP32.

We treat schools as a mission-aligned vertical: it is cheap, the education ministry budget can absorb it, and the actual public-health case is strong.

Indoor climate — museums

Quantified savings (per gallery, per year)

• One avoided conservation event. An RH drift past 60 % over a weekend can mean a €2000 conservator bill for a single panel painting. Averaged: €1000 / year amortised.
• Insurance premium / loan compliance. Bizot-compliant museums routinely have RH monitoring as a condition; OpenSense satisfies it for ~10 × less than the bespoke museum-environmental product market.

Total realised savings: ~€1000–€2000 / year. Cost: €348 / year + ~€150 per gallery for two RH probes. Payback: 3–6 months.

Energy

Quantified savings (per small workshop, per year)

• One leak found. Per the energy vertical: two failed dishwasher solenoids and one chronically-on fountain in our pilot. Each ≈ €300–€800 / year of avoided electricity / gas.
• Standing load anomalies. Catching a freezer with a failed gasket in the first week instead of after the next bill saves €100–€400 / year averaged.
• Phase imbalance. A laundry on three-phase with a heater wired imbalanced was paying ~€600 / year more than necessary in transformer losses and breaker derating; OpenSense flagged it; an electrician fixed it. Amortised: €200 / year.

Total realised savings: ~€800 / year typical, €1500 / year if a leak gets caught. Cost: €348 / year + ~€140 for a Shelly Pro 3EM. Payback: 6–8 months.

Caveats

• Every number on this page is averaged across hypothetical small operators. Your operation is not the average. If you have one fridge in your café and an inspector visits once a year, your HACCP ROI is closer to "the saved logbook hours" than to "the avoided fine". If you run a 40-room hotel, the Legionella ROI is dominated by the avoided incident.
• We do not promise the savings — we promise the measurement. The savings come from acting on the measurement; you have to do that acting.
• Where we cannot quantify (school air quality, museum conservation), we say so rather than fabricating. The conservative numbers in the HACCP and server-room sections are deliberately on the low end.