High velocity AC is a relatively common alternative to standard, ducted air conditioning. These systems blow air through narrow tubes, which terminate at small vents. High-velocity AC systems work well in older homes with radiator heating, and also in areas where energy-efficiency is a big concern. You might be thinking of having such a system installed in your own home, in which case it is a good idea to learn more about them first.

High velocity AC systems still have a condenser and an evaporator coil.

People often think of these systems as being small and compact, but that's really only true of the "ducts" associated with them. The air conditioning system will still include a condenser, which typically sits outside on a concrete pad, and an evaporator coil, which usually goes in a basement or crawlspace. If you are looking for an AC system that takes up less space, you may be better off with a heat pump or ductless mini split system instead of a high-velocity AC system.

High velocity AC does make some noise.

These systems are often touted as being quiet. They are usually quieter than most ducted AC systems since you won't hear metal ducts binging or banging. However, high-velocity AC is not silent. There is a rushing air noise created when the air blows through the tubes. This does not ultimately bother most people, but it can take some getting used to. If you have kids, be prepared to explain to them what the humming noise is when your AC first turns on. It does sound quite different from a standard AC noise.

High-velocity AC vents are usually placed near the ceiling.

You're probably used to seeing standard vents near the floor or even on the floor. But with high-velocity AC, the vents are really small and circular. They are often placed high up on the wall, near the ceiling, where they are out of the way. So, start thinking about where you want your vents before the installer arrives. There is often a lot of flexibility when it comes to choosing a location since the tubes that connect to the vents are easy to feed through and behind walls.

Now that you know a little more, you should be well prepared to have a high-velocity AC system installed in your home. These systems work well in many homes, but it is important to understand what you're getting before scheduling your new AC installation.