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Home Inspection Facts: What is High-Velocity Air Conditioning?

Home inspection

What’s cool, powerful and fits all over? High-velocity air conditioning, that’s what. This system is robust, compact, and in many homes, can cool more efficiently than a traditional air conditioning system.

If you’ve never encountered one before, here’s what you need to know.

High-Velocity Systems Have Unobtrusive Vents

Like any conventional air conditioning system, a high-velocity system extracts humidity, cools the air and circulates it back into the house. Unlike any other air conditioning, high-velocity vents are so small that you might not notice them unless you look close.

One of the beauties of this type of system is its ability to blend in with the home’s architectural details. Instead of the typical rectangular registers along the floor or ceiling edge, high-velocity vents or outlets, just a few inches in diameter, might be anywhere. In some installations, vents masquerade as a circular detail on a larger design, such as a ring on a ceiling medallion.

The Ductwork Fits in Almost Any Home

The characteristic small vents of a high-velocity system are connected to equally small ductwork. It’s only two or three inches in diameter, which is much smaller than traditional ductwork. It can run through closet corners, between wall studs and under a staircase where larger ducts can’t.

Smaller ducts make this a good choice for older homes. Where retrofitting conventional ductwork might require lowering a high ceiling, small ductwork can run between the joists. In homes where physical alterations would ruin the character, especially in historic houses, small ducts take up almost no space.

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The small ductwork needs generous sound-dampening, usually in the form of an insulated tube.

High Velocity Can be Noisy, but it Shouldn’t

The manufacturers weren’t joking when they named this type of air conditioning system. High velocity is powerful. It’s known for removing significantly more humidity than conventional air conditioning. Although they pack a punch, small ductwork and vents prevent the home from becoming a wind tunnel. But installed improperly, they’re loud.

Unico resident trainer, Pete Williams, tells ECI Comfort Solutions that the systems his company manufactures are quiet. Noisy systems, he says, are the result of too few outlets or vents, a kink in the ductwork tubing, or no “sound attenuator tubing,” which is the noise insulation that houses the ductwork.

They’re Expensive but May Eventually Worth It

Another drawback of high velocity is the cost. There are no bargain basement brands. And while the technology isn’t terribly new, it hasn’t been around long enough to catch on and bring about ample competition.

On the upside, this type of air conditioning is known for being so effective, a higher thermostat setting often feels cooler than a lower setting can with conventional AC. That circles back to how effective it is at extracting humidity. Less humidity feels cooler, so less energy is spent on cooling. The system could eventually pay for itself, and the homeowner will probably feel more comfortable the whole time.

High-velocity systems are primarily found in affluent neighborhoods and those where historic home preservation is a top priority. They’re slowly making their way into mid-grade homes, but again, the cost is a barrier for many homeowners.

If during an inspection you can’t find any registers, and there’s no ductwork in the attic to be found, don’t assume that the home lacks a central air conditioning system. The heat pump is probably outside. And tucked away between joists and studs, there might be a sophisticated system that blows the pants, almost literally, off conventional units.

If you’re ready to learn more about the different home systems you’ll encounter during a home inspection, there’s no better time to begin. Enroll now with ICA School home inspector training and work toward a whole new career.

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