How many misting nozzles does my terrace need?

The method

Use the area method for cooling an open space, and the perimeter method when you are treating the boundary (typical for mosquito control or for a terrace with a fixed edge).

• Area method: nozzles ≈ area ÷ 4. A 120 m² terrace → about 30 nozzles. Use ÷5 for a sheltered, humid site and ÷3 for a very dry, hot one.
• Perimeter method: nozzles ≈ perimeter ÷ 3.5. A 40 m perimeter → about 12 nozzles, aimed inward.
• Sanity check against the pump: one pump unit covers roughly 500–2,000 m² depending on application, so a terrace above about 2,000 m² is usually two units with parallel zoning rather than one very large one.

Worked examples

Three real shapes, three different answers — which is why a per-m² price is not meaningful.

• Small café terrace, 80 m², sheltered: ~20 nozzles (4 m² each), 1 zone, compact unit.
• Restaurant terrace, 300 m², partially exposed: ~75 nozzles, 2 zones, standard unit, nozzles grouped by prevailing wind.
• Hotel pool deck, 900 m², exposed: ~180–240 nozzles, 3–4 zones, larger unit; runs in rotating blocks so the deck is never wet.

Things that change the count

These are the reasons a quote sometimes comes back different from your own estimate — all of them are visible on site.

• Wind: an exposed site needs a denser ring on the windward side and fewer nozzles downwind.
• Ceiling or pergola height: mist above 3 m must be coarser to reach the seating level.
• Water hardness: hard water means higher filtration demand, not more nozzles, but it changes the maintenance schedule.
• Awnings and planting: they interrupt airflow; nozzles are placed to work with the eddies rather than against them.