Saunas sized for 1,795 metres

Altitude is in the sum, not a footnote

Thinner air carries less heat per kilowatt, so a heater chosen from a sea-level chart will underperform here. We start at roughly 0.85 kW per cubic metre of insulated cabin and apply an altitude correction before adding capacity for glass.

In practice that usually means going one step up the heater range compared with the same cabin at the coast, and we show that line in the quote rather than burying it.

The compensation: cool nights, cheap cold water

The same altitude that costs you heater capacity gives it back on the cold side. Nairobi nights are cool all year, so a shaded, insulated, lidded plunge tub works far less hard than the same tub in Mombasa, and the chiller cycles instead of running.

It is the single best thing about building wellness rooms in the Kenyan highlands and almost nobody selling equipment here mentions it.

Three countries, three specifications

Highland Nairobi: altitude correction, red murram dust in the dry seasons, no salt. A2 fixings are adequate inland and service is half-yearly.

The coast — Mombasa, Diani, Watamu: hot, humid and salty. A4 stainless throughout, sealed plant enclosures, deeper ventilated cavities, humidistat extract, and quarterly service with a corrosion inspection.

The bush — Mara, Amboseli, Laikipia: dust is the enemy rather than salt. Washable pre-filters, sealed plant housing, off-grid load sequencing and a three-month service interval in the dry season.

In short

• Altitude correction applied and shown for anything above 1,500 m
• Cool Nairobi nights mean the chiller cycles instead of running
• A4 stainless and sealed enclosures on the coast; dust packages in the bush
• 240 V single phase, 415 V three phase above 8 kW