Two-flats are everywhere in Chicago, and most of them were built long before air conditioning. Whether you live in one unit and rent the other or own both, the cooling choice usually comes down to ductless mini splits or some form of central air.
Start with what the building has
- Radiators and no ducts: mini splits or high-velocity systems.
- A furnace per unit with ducts: standard central air on each furnace is usually simplest.
- A shared boiler: cooling is separate anyway, so each unit can get its own system.
Side-by-side comparison
| Ductless mini splits | Central / high-velocity | |
|---|---|---|
| Ducts needed | None | Existing ducts or new small high-velocity ducts |
| Separate per unit | Easy: one outdoor unit per flat | Possible: one system per flat |
| Control | Each room | Whole unit |
| Heating too | Yes, most are heat pumps | Only with a heat pump |
| Looks | Wall heads visible | Small vents |
| Disruption | Low | Low to moderate |
Outdoor units and the gangway
Chicago lots are narrow. Outdoor units often go in the back yard, on a wall bracket, or on a flat roof. Two systems means two outdoor units, so placement and noise near neighbors’ windows are worth planning.
Electrical service
Older two-flats may need panel upgrades for two cooling systems. A technician checks this during the assessment.
Which to choose
For radiator-heated flats, mini splits usually win on simplicity and efficiency, and add heating in spring and fall. High-velocity central air suits owners who want whole-unit cooling with no wall heads. See ductless mini splits and AC installation, or call (312) 924-7223.