O&L Duct Design is a fully insured residential HVAC design company based in Tillsonburg, Ontario, serving builders, Architects, BCIN Designers, contractors, and homeowners across Ontario.

 

Owned and operated by Josh Dewachter, a certified Building Inspector and ticketed Sheet Metal Worker with over ten years of hands-on experience in both residential and commercial construction. O&L Duct Design delivers practical, code-compliant HVAC system designs rooted in real-world installation expertise.

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Residential HVAC Design Services

We provide complete, professional HVAC design packages that are permit ready, including:

• Heat Loss & Gain Calculations

• Ventilation Design & Layout

• Custom Duct Design & Sizing

• Code-Compliant Residential HVAC Plans

• On Site inspections 

• EEDS 

All designs are developed to meet applicable building code requirements while prioritizing system efficiency, airflow performance, and occupant comfort.

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Built for Builders, Contractors & Homeowners

At O&L Duct Design, we understand that a successful HVAC system begins with proper engineering and thoughtful layout. We create duct systems that are not only theoretically sound, but practical to install.

We focus on:

• Accurate load calculations

• Proper equipment sizing

• Optimized duct routing

• Balanced air distribution

• Energy efficiency and long-term performance

Our goal is to provide reliable, efficient HVAC designs that reduce installation issues, minimize callbacks, and ensure systems operate as intended from day one.

If you are looking for professional residential HVAC design services in Tillsonburg or surrounding Ontario communities, O&L Duct Design delivers accurate, efficient, and field-tested solutions you can build with confidence.