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Bryant Air ConditionerFor your commercial heating, ventilation, and air conditioning requirements, Welzig Heating and Air provides a superior level of service and products across Boulder, CO and surrounding areas.  By refusing to compromise our standards of quality, we ensure greater rewards for your investment.  Whether you’re in need of installation, seasonal upkeep, or prompt repair of your vital equipment, we take the opportunity to optimize performance with proven strategies, premier materials, and meticulous attention to detail.  For single-room offices and larger facilities alike, the health, safety, and comfort of the indoor environment is vital to smooth operation.  Let Welzig Heating and Air implement a plan to enhance productivity and minimize your bottom line.

Expert Commercial HVAC Services

Every commercial project is handled by factory-trained, NATE-certified, fully licensed, and experienced technicians from Welzig Heating and Air.  We take the time to determine your exact requirements and goals, and answer with a customized strategy and coordinated outline for each stage of the process.  Even complex installation projects are completed without delay, and we design a system that meets your specific requirements and offers a sustainable solution to projected business growth.

Leave complex commercial heating and cooling system repairs, maintenance, and installations to Welzig Heating and Air!

Our fleet of service trucks are fully prepared for any challenge with an extensive inventory of genuine manufacturer’s replacement parts, specialized tools, and leading-edge diagnostic equipment.  By completing the majority of services in a single visit, we protect against costly downtime and disruption.  Call on Welzig Heating and Air to enhance the value of your investment with regular, comprehensive maintenance, and to resolve any problems you might face.  Our team is always on-call, providing swift and skilled Emergency Service across Boulder, Longmont, Louisville, and Lafayette, CO, round-the-clock and year-round.

Satisfied Customers
They Speak For Us

Our 23-year-old A/C system ran out of “borrowed time” and became too difficult to continue maintaining. With great advice from Casey Welzig,, we replaced the old system with a Bryant Evolution A/C system. Max Loustaunau and Seth Bernhardt did an excellent job with removing the old system and installing the new one. Both of them are great to work with — very professional and very personable. We are really amazed at how much better the new system works!


Bob came out to look at our swamp cooler and was remarkably helpful and professional. Not only did he give me a knowledgeable diagnosis, but he also taught me a lot in the process. We’ll be calling him for all future needs with our cooling system.


Dave Kaplan-Gomez and James Miltersen installed my new Tankless Water Heater. Both were polite and professional. Care was taken not to damage anything in my house which I really appreciated. I use Welzig for all my HVAC needs and highly recommend them.

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