Room First · The EffectiV approach
Most HVAC systems are designed from the equipment down. Room First designs them from the occupants up: define what the room must deliver, engineer the air distribution to deliver it, then size everything upstream for what the room actually needs.
The room
Whatever is leftDefined first
Air distribution
Picked from a catalogue, lastEngineered for the room
Airflow
Whatever the ducts deliverCalculated for the room
Size
Ductwork
Follow the equipmentSized for that airflow
Size
Equipment
Chosen first, with marginSized last, to fit
Size
The shift
And start understanding it, predicting it and optimising it.
01 · Guessing
Capacity is chosen first. Ductwork follows. Airflow is whatever the ducts deliver, and the diffuser is picked from a catalogue at the very end, when the budget is already spent. What happens in the occupied zone is assumed: a default effectiveness value from a table, a throw read off a chart, comfort left to chance. The diffuser is the last link of the chain, usually the cheapest and the weakest.
02 · Understanding
Room First starts at the other end. Who occupies the room, doing what, for how long? What does comfort mean here: no drafts at desk height, no stratification under a high ceiling, warm air that actually reaches the floor in heating? How much fresh air must reach the breathing zone? Those requirements, not the equipment, set the targets.
03 · Predicting
Then we model it. SelectiV lays out the room, the diffusers and the ductwork in 3D and shows the airflow in heating and in cooling. For projects that need proof, Verified runs a CFD simulation under the actual operating conditions, following ASHRAE Standard 62.1: air velocity, temperature, mean age of air, thermal comfort (PMV/PPD), CO2 and the Ez factor, everywhere in the room.
04 · Optimising
With the room understood and the airflow predicted, the design is tuned: diffuser model, pattern, placement and airflow. High-induction diffusers mix the room more effectively, which raises air distribution effectiveness and lowers the load on equipment. Only then is the ductwork sized, and the equipment last, for what the room actually needs.
The design sequence
Conventional design reads this chain from the right. Room First reads it from the left.
← Conventional order Room First →
Air distribution effectiveness
ASHRAE Standard 62.1 divides the outdoor air a zone needs by its air distribution effectiveness, Ez. Perfect mixing is 1.0. Table 6-4 assigns default values to common configurations, as low as 0.8 for ceiling supply of warm air with ceiling return, and its Normative Appendix C lets a design demonstrate its real value with CFD. Poor mixing is paid for twice: in the air that must be conditioned, and in the comfort it fails to deliver.
Voz = Vbz / Ez
Zone outdoor airflow, ASHRAE 62.1 equation 6-2
Outdoor air to condition: +25% versus perfect mixing.
What it takes
Room First is not a product line. It is a way of designing, and it needs both halves.
01
High induction, long throws, self-adjusting thermal behaviour, architectural presence. Each model is tested and published so the prediction has data behind it.
★ BREEZ
BREEZ
★ AXO-S
High Induction Adjustable Square Swirl Diffuser
12″ x 12″, 24″ x 24″ · Plastic ABS Vanes, Steel
★ PLAY-S
360 Degrees Adjustable Sectors Square Diffuser
24″ x 24″ · Steel
★ LSD
High Induction Linear Slot Diffuser
Yes · Aluminum, PVC Vanes
★ KOO
Architectural Adjustable Long Throw Multi Nozzle Jet Diffuser
Yes · Aluminum, Galvanized Steel
★ KOBE
KOBE
02
Design software
Build the room and duct layout in 3D, run Auto-Design and visualise the airflow in heating and cooling before anything is manufactured.
Discover SelectiV
CFD validation service
Simulation of airflow, thermal comfort (PMV/PPD), mean age of air, CO2 and Ez factor per ASHRAE 62.1, under the room’s actual operating conditions.
Learn about VerifiedOn your project
A sequence that starts at the occupant, performance data to select from, and CFD validation per ASHRAE 62.1 when the project needs proof.
Diffusers designed to be seen: shapes, finishes and colours that belong in the space, with the performance to back the design.
Fewer drafts and complaints, better air where people breathe, and equipment sized for the real load rather than for a guess.
SelectiV · Verified
Use SelectiV to lay out diffusers in 3D, or ask for a Verified CFD study to validate comfort, IAQ and energy before anything is installed.
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