Adding central air to an older home without major ductwork

Many older homes in Michigan were built long before central air conditioning was common. They may have radiators or baseboard for heat, plaster walls, and little room in attics or walls for conventional ductwork. Adding cooling to these houses has traditionally meant window units. There are other options, and one of them is a high-velocity small-duct system.

How high-velocity systems work

A high-velocity system uses an air handler, usually in an attic or basement, connected to compact, flexible tubing. That tubing is much smaller than conventional ducts and can often be routed through existing cavities, closets, and spaces between framing with less disruption.

Air moves through the small tubing at higher speed and enters rooms through small round outlets. Instead of gently filling the room from a large register, the air mixes with room air as it enters, which helps distribute it evenly.

Why they suit some older homes

The main appeal is installation. Because the tubing is small and flexible, it can often be fished through walls and floors in ways that conventional ducts cannot. That can mean less cutting into plaster, fewer soffits, and more respect for the home's original character.

High-velocity systems can also be paired with heating sources, including hydronic coils connected to a boiler, so one air handler can contribute to both comfort needs. Whether that suits a particular home depends on the existing heating system.

How they compare with ductless

Ductless mini-splits are another common option for homes without ducts. They use wall-mounted or other indoor units connected to an outdoor unit with refrigerant lines.

A few considerations often come up:

• Appearance. High-velocity outlets are small and discreet; ductless indoor units are visible in each conditioned space.
• Installation. High-velocity requires routing tubing to each room; ductless requires running refrigerant lines to each indoor unit.
• Zoning. Ductless systems naturally allow room-by-room control; high-velocity systems typically condition the house more as a whole.
• Heating. Many ductless systems are heat pumps; high-velocity systems can be paired with several heating approaches.

Neither is automatically the right answer. The choice depends on the house, how the spaces are used, and the homeowner's priorities.

Things to know

High-velocity systems do sound different from conventional systems. Air movement at the outlets can be audible, though proper design and installation reduce this. Outlet placement matters for comfort, so the layout should be planned rather than improvised.

As with any system, sizing should be based on the home's actual cooling and heating needs. Older homes vary widely in insulation and air leakage, and those factors have a large effect on the right equipment size.

Planning the work

Installing a high-velocity system in an occupied older home requires planning: where the air handler will go, how tubing will reach each room, where the outdoor unit will sit, and how condensate will drain. It is worth discussing the likely routes and any areas that may need access before work begins.

If you are planning other renovations, coordinating the mechanical work with them can reduce disruption.

Is it a fit for your house?

If you live in an older home and want central cooling without large ducts, a high-velocity system is worth considering alongside ductless options. We can look at your home and talk through which approach suits it.