By BUILDER Magazine Staff. Chances are, when you install an HVAC unit in your homes it's an entry-level system that at the very least meets SEER 10 federal requirements. Nothing wrong with that. It provides a basic level of cooling efficiency for homeowners, and it doesn't blow your margins. But here is something you might want to consider: Will that unit sound like a 727 outside the window, or will it purr like a brand new Cadillac?

"In the past five years, the noise level of air conditioning units has become a big issue," says Matt Schulz, product manager for Amana Appliances. "Builders are building on tighter lots and AC units are getting bigger so they need to be quiet."

A noisy unit that sits outside the window of a homeowner is a big issue in itself, says Mark Ritz, marketing manager for York in Norman, Okla., but on a tight lot it means that it will disturb the neighbor as well, and this is an even bigger problem.

But unlike SEER standards, noise levels are not mandated by federal regulations, though some municipalities have their own rules. There also is no industry standard that manufacturers must meet. Some manufacturers, however, are striving to make units as quiet as they can be.

Ritz says a typical low-end unit might have a noise level of about 78 to 82 decibels, but the best units are about 72 to 78 decibels. Dallas-based Lennox Industries recently introduced AC and heat pump units that come in at 68 decibels. The general sound level in the average home is about 40.

A good step-up AC unit will cost about 30 percent more than a standard entry-level unit, so the switch to more quiet systems is unlikely to happen overnight. But if building trends continue, you might not have to make the decision to upgrade to quiet, efficient units; home buyers who want peace and quiet might make it for you.

Courtesy Amana

Prestige piece: The RCE Prestige Ultra remote cooling unit has a SEER 14 rating with a furnace coil and up to SEER 16.50 with the maker's blower and coil attachment. The unit's condenser fan operates at 850 RPM and features a sound blanket, so it also carries the manufacturer's lowest sound number at about 72 decibels. It features a high-performance compressor with overload protection, refrigeration-grade copper tubing, and aluminum fin coils. Amana. 877-254-4729.

Courtesy York

Split up: Most air conditioning systems operate at full speed even when a home needs less cooling power, but the new Olympian TS Series Split-System is designed to keep homes comfortable during non-peak times by running at a reduced workload. This translates into reduced energy costs and less noise. Compared to conventional conditioners, the unit uses less than half the energy needed to run the compressor and up to 65 percent less to power the blower fan when operating in non-peak mode. It has a SEER 12.7 or SEER 13.3 depending on the model. York. 405-364-4040.

Courtesy International Comfort Products

Soft sounds: The Comfortmaker SoftSound 1000+ heat pump has a 10-SEER efficiency when straight matched with standard coils but has a 12 rating when matched with variable speed blowers or furnaces. Available in 1 1/2- to 5-ton capacity, the unit comes with scroll compressors to produce minimal sound at maximum performance. Top discharge provides quieter performance, the maker adds. International Comfort Products. 615-359-3511.

Courtesy Lennox

Silent night: The Signature Collection HSX15 air conditioner is the quietest central air conditioner you can buy, the manufacturer claims. Featuring SilentComfort technology, the unit has a new fan blade design and a cabinet with an insulated compressor compartment. The manufacturer says the typical air conditioner is 16 times louder than the HSX15, which has a decibel rating of 68 and a SEER 15.75 rating. Lennox. 800-953-6669.