Open-plan layouts—living, dining, and kitchen in one connected space—need different AC planning than separate rooms. Airflow, placement, and capacity all matter. Here’s how to cool large open spaces effectively.
Why Open Plans Are Different
No walls mean a single large volume of air to cool. Heat from kitchen, sunlight from multiple windows, and high ceilings all increase cooling load. One undersized AC will struggle; placement affects how evenly cool air reaches every corner.
Capacity for Open Plans
Add the total square footage of the open area. For 300–400 sq ft, you typically need 2–2.5 ton. For 400–600 sq ft, 2.5–3.5 ton. High ceilings (10 ft+) add 10–15% to capacity needs.
| Open Area (Sq Ft) | Suggested Tonnage | Notes |
|---|---|---|
| 200 – 280 | 2 Ton | Small open plan |
| 280 – 400 | 2.5 – 3 Ton | Typical living-dining |
| 400 – 550 | 3 – 3.5 Ton | Large open plan |
| 550+ | Dual AC or 4+ Ton | Consider multiple units |
AC Placement for Better Airflow
- Central position: Mount the indoor unit where airflow can reach most of the space.
- Aim away from hot zones: Avoid pointing directly at kitchen or sun-facing windows if possible.
- Use ceiling fans: Fans help circulate cool air and reduce hot spots.
- Avoid corners: Corner mounting can create dead zones; centre or mid-wall is better.
Single Large AC vs Dual Units
For 400+ sq ft, two smaller units (e.g. 1.5 + 1.5 ton) can give better coverage than one 3-ton unit, especially if the space has distinct zones. See multi-room cooling for comparison.
Tips to Reduce Load
- Use curtains or blinds on sun-facing windows.
- Run exhaust fan when cooking to remove heat.
- Keep doors to bedrooms closed if you only cool the open area.
Estimate Running Cost
Use our AC Energy & Cost Calculator with your chosen tonnage. For room sizing basics, see right AC capacity for room size.
FAQs
How many tons for open plan living-dining?
For 300–400 sq ft, typically 2.5–3 ton. For 400–500 sq ft, 3–3.5 ton. Adjust for ceiling height and sun exposure.
Why is one side of my open plan warmer?
Often due to airflow direction, sun exposure, or kitchen heat. Improve with ceiling fans or a second AC in the warmer zone.
Should I use one large AC or two smaller ones?
For very large spaces (500+ sq ft), two units can improve coverage. For 300–400 sq ft, one correctly sized unit usually works.
Do ceiling fans help in open plan?
Yes. They circulate cool air and reduce hot spots, allowing you to set the AC 1–2°C higher and save energy.
Does inverter AC help in open plan?
Yes. Inverter ACs modulate and handle varying loads better, which suits open plans with changing occupancy and heat.
Where should the outdoor unit go for open plan?
Follow standard placement rules: shaded, ventilated, accessible. See outdoor unit placement for details.
Conclusion
Open-plan cooling needs right capacity, smart placement, and good airflow. Size for total area, mount for even distribution, and use fans to assist. For very large spaces, consider dual ACs.