Sure, you need to floor residents with sparkling hardwoods and plush carpeting. But in the mad dash to find the best-looking product, don't forget that what's underneath the pretty floor is just as critical to the success of an apartment or condo community.

One hidden feature you can't afford to forget: a sound-deadening system. "If you just spend a few million dollars on a condo, the last thing you want to hear is someone walking around above your unit," says Edward Baquero, managing partner of COALCO International, which is developing ELEMENT, a luxury 193-unit condo in New York City. The New York-based developer hired an acoustic engineer to ensure the highest level of sound control–and in fact, the building's floors will exceed local sound code requirements. "The transferring of sound has to be really engineered," says Baquero. "You have to be very careful, right down to the glue being used on the floor."

SOUND CHECK: This laminate floor offers more than just good looks. Sonic Floor is equipped with an underpad made of felt and rubber to help significantly diminish impact noise. The product replicates the look and feel of hardwood in wood grain or embossed wood grain finishes and installs as a simple click-and-lock system. The eco-friendly floor is made with wood from FSC-certified forests.

To make the process easier, manufacturers offer floors with built-in sound-proofing properties (as opposed to layering such products under wood or laminate floors). Kronopol, an Ontario, Canada-based flooring manufacturer, recently introduced laminate flooring equipped with a felt and rubber underpad that significantly diminishes impact noise with a field-tested impact insulation class of 58, higher than some states require. (Building codes typically require a minimum rating of 45.)

Sound-deadening materials aren't the only thing lurking beneath those floors: Developers are warming up cold kitchen and bathroom stone and tile floors with electric heating systems. "It's a nice, toasty amenity on cold days," says Evan Haymes, principal developer of New York-based Bronfman Haymes Real Estate Partners, which is offering the product at the luxury mid-rise ONYX Chelsea under development in New York City. Residents will be able to adjust the temperature via a handy thermostat.

Toasty floors aren't just limited to super high-end products. "Middle- market consumers are willing to trade up to more luxury goods and items," says Nicolas Mottet, marketing communications manager for WarmlyYours, an electric floor heating manufacturer. "We see the rise of Starbucks coffee, Victoria's Secret, and Absolut Vodka–luxury goods that are still affordable and accessible to a household making $50,000 to $100,000 a year." Who wants to sip gourmet coffee on a cold floor?