Office · Ventilation
Ventilation in office: what the SRI measures
Ventilation is about demand-controlled ventilation: more air when more people are present or CO2 rises, less when a room is empty. Heat recovery, free cooling with outdoor air and air-quality reporting count as well.
In short
- 1This page shows how the Smart Readiness Indicator assesses ventilation in office buildings.
- 2The ventilation domain has maximum weighting for offices, with a weighting factor of 3 out of 3.
- 3Six smart-ready services together determine the score, from air flow per room to air quality reporting.
Weight of this domain for this building type
Which services count
| Service | Lowest level | Highest level | Advice |
|---|---|---|---|
| Supply air flow control at the room level V-1a · A · 5 levels | No ventilation system or manual control | Local Demand Control based on air quality sensors (CO2, VOC, ...) with local flow from/to the zone regulated by dampers | highest level |
| Air flow or pressure control at the air handler level V-1c · 5 levels | No automatic control: Continuously supplies of air flow for a maximum load of all rooms | Automatic flow or pressure control with pressure reset: Load dependent supplies of air flow for the demand of all connected rooms (for variable air volume systems with VFD) | – |
| Heat recovery control: prevention of overheating V-2c · 3 levels | Without overheating control | Modulate or bypass heat recovery based on multiple room temperature sensors or predictive control | – |
| Supply air temperature control at the air handling unit level V-2d · 4 levels | No automatic control | Variable set point with load dependant compensation. A control loop enables to control the supply air temperature. The setpoint is defined as a function of the loads in the room | – |
| Free cooling with mechanical ventilation system V-3 · 4 levels | No automatic control | H,x-directed control: The amount of outside air and recirculation air are modulated during all periods of time to minimize the amount of mechanical cooling. Calculation is performed on the basis of temperatures and humidity (enthalpy) | – |
| Reporting information regarding IAQ V-6 · A · 4 levels | None | Real time monitoring & historical information of IAQ available to occupants + warning on maintenance needs or occupant actions (e.g. window opening) | highest level |
Worked example
If everything in this domain is at level 0, the domain contributes nothing. At the highest level for all services, the indicative total score for this building type rises by about 10 percentage points (from 31 to 41 percent, with all other domains at level 1).
Why does ventilation count so heavily in offices?
Offices have varying occupancy by day and by hour. An air handling unit running at full capacity at all times wastes energy once rooms are empty.
The Smart Readiness Indicator (SRI) measures how well a building can adapt to this. For offices, the ventilation domain receives the highest possible weighting factor: 3 out of 3.
This is because lighting and ventilation, alongside climate control, are the largest energy consumers in an average office building.
Which smart-ready services fall under ventilation?
The SRI methodology examines six services within this domain. Each service has functionality levels from 0 (no automation) to 4 (fully demand-driven).
- V-1a: control of supply air flow per room, from manual operation to local control based on air quality.
- V-1c: control of air flow or pressure at the level of the air handling unit.
- V-2c: control of heat recovery to prevent overheating.
- V-2d: control of supply air temperature, with or without load compensation.
- V-3: free cooling with the mechanical ventilation system, up to and including control based on temperature and humidity.
- V-6: reporting of air quality information, up to and including user alerts.
A building management system (BMS) is often already present in many offices, but not always properly tuned for these functions.
What does this mean for an office's score?
Each service is assessed against seven impact criteria, including energy efficiency and comfort. Three key functionalities carry equal weight.
Because the ventilation domain has maximum weighting for offices, progress here directly affects the overall score. That score is expressed as a percentage and placed into one of seven classes, ranging from below 20 percent to 90 to 100 percent.
Offices with an air handling unit above 290 kW often fall under the building automation requirement in Article 13 of the EPBD (Energy Performance of Buildings Directive). The SRI itself remains voluntary, although a delegated act is expected to come into force by 30 June 2027 that will make the SRI mandatory for utility buildings above that threshold.
What this means for you
- Owner
- Have the building management system checked for the functionality levels of the six ventilation services, especially V-1a and V-1c, as varying occupancy can save considerable energy here. A higher score on this domain carries significant weight in the overall SRI score, given the maximum weighting factor for offices.
- Tenant
- An office with demand-driven ventilation noticeably feels fresher in busy rooms and less draughty in empty ones. Real-time air quality information (service V-6) may be visible via a display or app in the building.
- Advisor
- Check whether the air handling unit already controls demand-based on CO2 or humidity, or still operates on a fixed schedule. Also look at the presence of heat recovery and free cooling, as both services count towards this heavily weighted domain.
Next step
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