Our Certifications at WM J Kraus & Son Our team at WM J Kraus & Son in Keokuk aims to provide the best heating and cooling service around. The primary way we sustain our expertise and continue to build knowledge about HVAC products is by earning industry certifications. Learn more about the certifications our technicians have received below. Better Business Bureau WM J Kraus & Son is a member of the Better Business Bureau. That means we operate by ethical business behaviors and give trustworthy information to our customers. We have a solid rating and are proud to be part of this organization.