The box fans are out again
If you're reading this, the box fans have probably already come out of the closet, and the window units are propped in at least one or two rooms. That's the usual summer pattern in older Springfield neighborhoods, Rountree, Woodland Heights, the brick bungalows and Craftsman homes near downtown that went up before 1950. They were built for cross breezes and tall ceilings, not for the kind of July and August we get now, with heat index numbers that sit in the upper 90s for days and the humidity that rolls up from the Ozarks and just parks over the city.
These houses don't have ductwork because nobody needed it when they were built. Coal or gas furnaces heated them room by room, or through a single floor grate. That means central air isn't a simple swap. It's a bigger question: where does the duct system even go in a house that was never designed to hold one.
What's actually different about these old houses
Plaster walls and lath, not drywall. Balloon framing in a lot of cases, where the stud cavities run uninterrupted from the basement to the attic. Floor joists that weren't notched for anything bigger than a knob-and-tube wire. All of that matters once you start asking a contractor to run supply and return ducts through the house.
Basements in this part of Missouri are often low-ceilinged, sometimes partially finished, sometimes damp enough in spring that you already know about it from the sump pump running. Attics tend to be tight, with little room to stand, let alone route sixteen-inch trunk lines. None of this makes central air impossible. It just means the ductwork has to go somewhere that wasn't planned for it, and that somewhere is usually a compromise.
More on this from Reading List Adding Central Air To A House Built Before Ducts Existed.
What you can check before anyone else gets involved
Walk your attic with a flashlight and see how much headroom and joist space you actually have. Look at your basement ceiling for the same thing, exposed joists give a contractor room to run lines without tearing into plaster. Note where your closets stack on top of each other floor to floor. A chase built through stacked closets is one of the more common, least invasive ways to get ducts from a basement system up to a second floor.
Check your electrical panel while you're at it. Many of these homes have been upgraded over the decades, but some still run 100-amp service, and a central air compressor plus air handler will want more headroom than that, especially if you're also running electric heat strips or a furnace blower off the same panel.
None of this tells you exactly what the final system will look like, but it tells you whether you're dealing with a straightforward retrofit or a harder one, and it gives you real information to bring to the first conversation with a contractor instead of walking in blind.
Where this stops being a homeowner project
Once you're past the walkthrough, the work itself isn't something to take on solo. Sizing a system for a 1920s house with plaster walls and original windows is different from sizing one for new construction. These houses leak air in ways a load calculation has to account for, and an oversized system will cycle on and off too fast, leaving the place clammy even with the AC running. Undersized, and it'll run constantly through August without ever catching up.
There's also the question of whether to go with a traditional ducted system routed through chases and soffits, or a smaller high-velocity system that uses two-inch flexible tubing snaked through wall cavities, which tends to be the better fit for houses with no existing chases at all. That decision needs someone who's actually opened up houses like yours around Springfield and seen what's behind the plaster, not just read the blueprints.
What the season actually asks of a system here
Springfield's climate isn't brutal in the way Phoenix or Houston is, but it's demanding in its own way: real winters that call for heat, summers that are hot and wet enough that a central system has to dehumidify as much as it cools, and shoulder seasons in spring and fall where storms roll through and knock the power out for a few hours at a time. A system installed here needs to handle all of that, not just blast cold air in August.
If you're adding central air to a house that never had it, this is also the moment to think about whether you want heating handled by the same ductwork, since running both through the same chases is far more practical than doing it twice. That's a conversation worth having early, before any ducts actually go in the walls.