Portable air conditioners: the honest last resort

Portable ACs are the least efficient way to buy cold air in America — which is exactly why the DOE forced the industry to publish SACC (Seasonally Adjusted Cooling Capacity): the honest rating that accounts for duct losses and infiltration. A unit marketed at « 12,000 BTU (ASHRAE) » typically delivers 7,000–8,000 BTU SACC. Always compare SACC to SACC; the marketing number overstates real cooling by 40–50%.

Physics explains the gap: a single-hose portable exhausts indoor air outside, pulling hot outdoor air in through every crack to replace it. Dual-hose designs fix half the problem and are worth their premium. The legitimate use cases mirror the French market’s: renters barred from window units, rooms with unusable windows, and server or hobby spaces needing spot cooling. Everywhere else, a window unit at half the price cools better.

Frequently asked questions

Single-hose or dual-hose portable?

Dual-hose, if a portable at all: the second hose draws condenser air from outside instead of stealing conditioned indoor air, improving effective cooling by roughly 20–40% in hot weather and reducing the infiltration that single-hose designs cause.

Why does my portable AC barely cool the room?

Stack the usual suspects: marketing BTU vs SACC reality, hot exhaust hose radiating heat back into the room (insulate it), leaky window kit (seal it), and a room bigger than the honest capacity. A single-hose 8,000 BTU-class portable realistically manages ~200 sq ft of decently insulated space.

By state and by size

State rules and climates: all 50 states. Sizing: BTU by square footage. Brands: Carrier, Trane, Lennox, Goodman, Midea.

Other equipment types: Central AC · Heat pump · Mini-split · Window AC.