D & T Service, Inc. has been a reliable name in HVAC since 1978. What started as a small family-owned operation has grown into a trusted heating, cooling, and refrigeration company serving thousands of homes and businesses across the Frankfort, IL region.

We’ve built our reputation on honest work and long-term relationships. Our technicians treat every job — from a quick tune-up to a full commercial rooftop replacement — with the same care, respect, and attention to detail.