Add another selling point for new homes—homeowners consider them healthier than homes built before 2001, according to the Houzz 2014 Healthy Home Trends Study.

Houzz, an online platform for design and remodeling, surveyed 808 homeowners nationwide, asking them to rate the health of their homes when considering factors like air quality, comfort, pest control, and security.

What makes a house healthy? More than 60 percent of respondents rated their homes as healthy and more than half highlighted comfort; exposure to chemicals; exposure to germs; and security as factors very important to health and well-being.

A third (33 percent) of respondents rated their homes as very healthy, while only 5 percent rated their homes as very unhealthy. The homes perceived to be most healthy shared some common traits, including being built more recently, lacking the presence of rodents or mold, and exhibiting more light.

The survey found that by generation, Baby Boomers and Gen Xers tend to be more critical of the health of their homes than Millennial homeowners. Overall, 20 percent of homes rated healthy (which includes homes rated very or somewhat healthy) were built after 2001. Only 13 percent of homes rated unhealthy (which includes homes rated neutral, somewhat or very unhealthy, or unsure) were built after 2001. A total of 22 percent of homes built before 1950 were rated healthy, versus 27 percent rated unhealthy.

Homes in the Midwest were rated healthiest by region, with 63 percent rated as healthy. But the West comes a close second, at 62 percent, while 58 percent of homes in the Northeast and South were considered healthy by homeowners. The survey also found that "preventing health problems" is a leading motivator in more than 40 percent of remodeling efforts undertaken by homeowners.

Read the full survey results from Houzz.