Seattle and London Share Summer Weather, but Far More Seattle Homes Have Air Conditioning

London and Seattle have near identical summer highs, yet about 5% of London homes have air conditioning, compared with over 50% in Seattle. Climate explains part of Britain's low adoption, but it is far from the whole story. The walls help explain the rest.

A typical American wall starts as timber framing, a skeleton of vertical boards called studs, spaced 16 or 24 inches apart. Before the wall is sealed, the gaps between those studs stand empty. With those cavities exposed, crews can thread wiring, plumbing, and the broad tubes that move heated and cooled air with little extra cutting or patching.

That ease shapes heating choices, in part. Because air channels fit readily inside open frames, American homes often use ducted heating. With ducts already in place, linking in an outdoor condenser to the same network is a small extra step that many owners find worthwhile even if it runs only during an occasional heat wave.

A typical English wall offers no such opening. It is solid brick, with no hollow space to conceal large air tubes. What passes more readily through brick is slim pipe carrying hot water, so English homes often heat with radiators. Adding cooling then is a whole separate project, typically requiring separate cooling boxes in each large room that are noisy and stand out.

The same openness speeds later work. Insulation comes in rolls cut to match the stud spacing, and interior drywall fastens straight to the wood. An inexpensive new house in an American subdivision can reach that stage within two months, while an English house at two months can still be in bricklaying. The American method buys a cheaper build with easy cooling, while the English method buys stronger walls and roofs that last longer.