What happens to your AC when guests go out for the day?

When rental guests leave for the beach, the AC stays on. There is no sensor, no timer, no smart system detecting the absence. The unit runs in an empty room until guests return, for four, five, sometimes six hours straight.

A typical rental day, hour by hour

Tracking the AC in a Mediterranean holiday rental across a standard guest day reveals a consistent pattern. The absent-room hours are not marginal, they are a substantial part of every occupied day.

On this typical day, the AC runs for roughly 14 hours. Of those, 6–8 hours involve no guest in the room. That is the unattended portion, the portion that could be eliminated without any impact on guest comfort.

Why sensors don't solve this problem

Motion sensors or occupancy detectors seem like the obvious solution: detect when the room is empty, shut off the AC. The problem is that sensors are not reliable in a rental context.

Guests who arrive back from the beach to a hot room (28–30°C) are not happy. Sensor-based systems that shut off AC during absence reliably produce this outcome. The room reheats, guests return hot, and the sensor-shutoff becomes a source of frustration and negative reviews, particularly in peak summer heat when the room can return to ambient temperature quickly.

The more subtle problem is that sensors cannot distinguish between a guest who has left for four hours and a guest who is sitting quietly reading. Both produce the same sensor output: low or no motion. Shutting off AC in the latter case is clearly wrong; both cases look identical to the sensor.

Runtime control solves a different problem: it limits how long AC can run continuously in one block, resetting automatically on a timer. Guests who return and switch AC back on get immediate cooling. The system does not assume the room is empty, it simply prevents indefinite uninterrupted operation.

The financial impact of absent-room AC runtime

In a Mediterranean warm-climate rental running a 120-night season, with an average of 4–6 hours of daily unattended AC operation, the cost of that absent-room runtime represents a substantial fraction of total AC electricity costs. It is also the most directly addressable fraction, unlike overnight setpoint waste (which requires a minimum temperature limit), absent-room waste is captured almost entirely by a runtime limit that resets on a regular interval.

Operators who install Narveo and set a 45-minute runtime limit see the largest portion of their electricity savings coming from this exact pattern: the beach-absence block no longer runs as a single uninterrupted session. The AC runs, reaches its limit, shuts off, and waits. When guests return, one button-press restarts it.

What guests experience

This is the question operators worry about: will guests notice? Will they complain?

In practice, guests returning from the beach do not notice that the AC has been off for part of their absence. They notice whether the room is cool when they arrive. A unit that has been off for 45 minutes in a well-insulated room (common in Mediterranean properties built in the last 20 years) typically still feels cooler than outside. Guests press the remote, the AC restarts, and the room is comfortable within minutes.

The only failure mode is a poorly insulated property in extreme heat (40°C+) where a one-hour absence produces a room that is uncomfortably warm. In those cases, operators typically set the limit at 60 or 90 minutes rather than 45. The default setting covers the large majority of Mediterranean rental properties.

When Narveo is not the right solution

Narveo's runtime limit works best in warm-climate rentals where split AC units run during a 4–6 month peak season. In cool climates, or where occupancy is low, the absent-room problem is proportionally smaller. Narveo is not compatible with ducted systems or centralised BMS. In owner-occupied properties, the absent-room pattern is different and the return is lower.