Our Certifications at C-N-O Comfort Zone We’re passionate about providing the Saint Peters community with the most responsive heating and cooling service in the area. To help us do this, we’ve gone through rigorous training to receive the industry certifications you see below. Find out more about our certifications here and give us a shout at 636-255-8997 to speak with a team member. Better Business Bureau C-N-O Comfort Zone is a member of the Better Business Bureau, meaning we follow ethical business practices and communicate reliable information with our customers. We have a strong rating and are proud to be part of this organization.