Solution 2 — kW of Cooling Capacity ‑ Cooler Sizing & Verification (@80 Pa Outlet Check)

Category: Sizing / Design / Replacement / Changeover→ Evaporative Cooling
Title: Evaporative Cooler Sizing by Cooling Capacity (kW) with Outlet Verification (@80 Pa)
Summary: Step‑by‑step method to size replacement evaporative coolers by cooling capacity (kW) using regional guides and home size bands, then verify outlet capacity @80 Pa. Includes performance tables, worked examples, and technician checklist.


Evaporative cooler sizing guide using cooling capacity (kW) with outlet verification at @80 Pa. Includes regional kW requirements, home size bands, performance tables, high‑airflow legacy replacement notes, and a full workflow for confirming model selection, outlet capacity, and dropper compatibility. Covers EXS, LCQ, LCQV, LPQV, CPQ, BMQ and RPSI models, with worked examples and technician checklists.


1) Notice on this information

Provides a kW‑first sizing method for selecting a replacement evaporative cooler, then a method to verify the duct/outlet system can deliver the required airflow at @80 Pa.

2) Sizing Fundamentals

  1. Calculate/estimate required cooling capacity (kW) for the property (see Sections 4–5).
  2. Select current models whose kW of cooling capacity meets or slightly exceeds the requirement.
  3. Check airflow @80 Pa for the selected models (Section 6).
  4. Verify outlet capacity can deliver ≥ the coolers @80 Pa airflow (Section 7).
  5. Confirm dropper compatibility, structural integrity, and installation constraints.

3) When to use kW of cooling capacity‑based sizing when replacing existing coolers

  • Replacing high‑airflow axial legacies (e.g., TCL140/160; SVA 400/450)
  • Homes with high ceilings (3.0 m), complex layouts, or large open areas
  • Climate‑sensitive regions where latent/sensible loads vary
  • Any situation with uncertain legacy airflow equivalence

4) Home Size Guide (Approximate)

  • Small: 60–100 m²
  • Medium: 100–140 m²
  • Large: 140–170 m²

Use upper‑range kW for 3.0 m ceilings and multi‑room layouts.

5) Quick Cooling Area Sizing Guide (kW by region)

Perth (Hot/Dry)

  • Small: ~10–12 kW
  • Medium: ~13–15 kW
  • Large: ~14–15 kW+

Adelaide (Moderate‑Hot)

  • Small: ~8–10 kW
  • Medium: ~10–13 kW
  • Large: ~13–15 kW

Melbourne (Mild)

  • Small: ~8–9 kW
  • Medium: ~9–12 kW
  • Large: ~12–14 kW

Albury (Warm Inland)

  • Small: ~9–10 kW
  • Medium: ~11–13 kW
  • Large: ~13–15 kW

Tamworth (Hot Inland)

  • Small: ~10–12 kW
  • Medium: ~13–15 kW
  • Large: ~14–15 kW+


Use upper‑range kW for 3.0 m ceilings and multi‑room layouts.

6) Current Model Performance (2025–26)

Use these to confirm your selection and verify that the number and size of existing or proposed outlets can deliver the required airflow @80 Pa 


Brand / SeriesModelCooling Capacity (kW)Airflow @ 80 Pa (L/s)
Breezair – EXSEXS16010.81720
EXS18011.62070
EXS20014.32320
EXS22015.12540
Braemar – LCQLCQ35010.21890
LCQ45013.22570
LCQ55014.12800
Braemar – LCQVLCQV2508.11500
LCQV3509.91990
LCQV45013.52620
LCQV55014.33070
Braemar – LPQVLPQV35010.42010
LPQV45011.82390
LPQV55013.22850
Coolair – CPQCPQ4508.01570
CPQ7009.52000
CPQ85011.82560
CPQ110013.32710
Braemar – BMQBMQ6506.91380
BMQ8509.22070
BMQ115012.02390
Braemar - RPSIRPSI25009.0 D/T Chillcel / 8.3 Side Chillcel 2130
RPSI280010.8 D/T Chilcell / 9.1 Aspen

9.7 Side Chilcell  / 9.7 Aspen		2530

7) Outlet Capacity Verification Method (@80 Pa)

Rule: Total outlet airflow must be ≥ cooler airflow @80 Pa.

Typical Outlet Airflows

Outlet SizeTypical L/sNotes
300 mm150–170Small rooms
350 mm250–300Most common
400 mm350–400Larger rooms
450 mm450–500High airflow
500 mm550–600Large open areas

Procedure

  1. Count outlets by size.
  2. Assign typical L/s per size (use mid-points unless measured).
  3. Sum outlet L/s to get Total Outlet Capacity.
  4. Compare total against selected model @80 Pa airflow:
    • Total ≥ @80 Pa → PASS
    • Total < @80 Pa → FAIL → add or upsize outlets.

Worked Example

  • System: 6 × 350 mm + 2 × 400 mm
  • Typical: 350 mm ≈ 300 L/s, 400 mm ≈ 400 L/s
  • Total = (6 × 300) + (2 × 400) = 2600 L/s

Model Check (@80 Pa)

  • EXS220 → 2540 L/s → PASS
  • LCQ450 → 2570 L/s → PASS
  • LCQV450 → 2620 L/s → Borderline PASS
  • LPQV450 → 2390 L/s → PASS
  • LPQV550 → 2850 L/s → FAIL → add/upsized outlets required

8) Step‑by‑Step Sizing Workflow (kW‑First)

  1. Measure/estimate floor area and ceiling height.
  2. Select regional kW band (Section 5).
  3. Pick candidate models matching required kW (Section 6).
  4. Check @80 Pa airflow for the candidate.
  5. Verify outlet capacity (Section 7).
  6. Confirm dropper size, roof opening, and structural fit.
  7. Complete installation planning and commissioning.

9) Special Notes (High‑Airflow Legacy Axial)

  • Legacy models TCL140/160 and SVA 400/450 may have higher nominal airflows than modern units.
  • Do not match on airflow alone. Select by kW, then ensure duct/outlet capacity supports the chosen model @80 Pa airflow.

10) Technician Checklist

  • ✔ Confirm required kW from region & home size
  • ✔ Select model with matching kW
  • ✔ Verify @80 Pa airflow and outlet capacity
  • ✔ Check dropper size and condition
  • ✔ Validate ductwork layout, room distribution, and crossflow
  • ✔ Chillcel pads have improved efficiency over old style Aspen (woodwool) pads

11) References & Further Reading


Always verify current specifications prior to final selection/installation.