Where the ducts live
Most American metros picked a side. Memphis did not. Drive from Central Gardens to Southwind and the houses change foundation halfway: crawl spaces under the older neighbourhoods, slabs under most of what was built east after the war. That single difference decides where the ductwork runs — and duct trouble is the most under-diagnosed comfort complaint in the city.
- 1 Thermostat — The season’s odometer — a hundred cooling days pass through it.
- 2 Return and filter — The lungs, and the first thing a retrofit house sized too small.
- 3 Air handler and furnace — Up in the attic, asleep nine months, asked for everything in December.
- 4 Coil and condensate drain — Litres of river-valley moisture a day, leaving through one narrow line above your ceiling.
- 5 Attic ducts — The coldest air in the house, commuting through the hottest room on the property.
- 6 Outdoor unit — Full sun, full load — where August culls capacitors by the thousand.
Overhead: the attic houses
On a slab, the distribution goes up. Flexible duct runs snake across the ceiling joists, through a space that spends July somewhere far above the outdoor temperature, and the coldest air in the house makes its commute through the hottest room on the property. Even sound insulated duct gives up part of its cooling on that trip — that loss is designed for. What is not designed for is what age adds: insulation slumped off the joints, flex crushed under stored boxes or sagging between supports, connections taped decades ago that have let go.
The tell from inside is unevenness, and it is always worst at distance: the far bedroom that never reaches setpoint, the bonus room that surrenders by three in the afternoon. The reflex is to blame the equipment and buy bigger — which feeds the same leaks with more horsepower and hands the oversizing problem its excuse.
Underfoot: the crawl-space houses
In Midtown, Cooper-Young, Evergreen and the older streets east of the parkways, the ducts run below the floor instead. Different space, different physics: a vented crawl space in Memphis humidity stays damp, and cold supply ducts passing through damp air sweat like a glass of iced tea. Wet duct insulation compresses and stops insulating; metal corrodes; the fibreglass sags away from the joints. A duct system can fail from the outside in without a single hole in the sheet metal.
Leaks behave differently down here too. On the supply side you pay to cool the crawl space; on the return side the system inhales crawl-space air — the dampest, dustiest air on the property — and hands it to the house with every cycle. Filters load faster, registers dust faster, and nobody connects it to a space they have not opened in years.
The question that sorts it
Before any equipment conversation, the useful question is simply where your ducts are — and a homeowner can usually answer it in a minute. A slab house with ceiling registers has attic ducts. Floor registers mean a crawl space beneath. Some Memphis houses have both, because an addition arrived later on a different foundation than the original.
It matters because the fixes are different. Attic runs want sealing, insulation restored to depth and re-support. Crawl runs want that plus a look at why the space is wet in the first place. And any replacement quote in this city that never mentions which of the two you have was written from the driveway.