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Dependable Boiler Services

For residential or commercial boiler services in Boulder, Colorado, reach out to Welzig Heating and Air with no doubt of our ability and determination to satisfy every need. Our NATE-certified technicians are trained, experienced and prepared for every make and model of hydronic heating system. Along with flexible scheduling and prompt arrival during regular business hours, we further protect your comfort with 24/7 emergency response.

Established in 1994, Welzig Heating and Air remains a family owned and operated HVAC company. We are a Google Guaranteed Service Provider, BBB accredited business in good standing and a Bryant Factory Authorized Dealer. For unwavering demonstration of excellence, we’ve won the Bryant Circle of Champions Award three years in a row. Our efforts to exemplify our field translate into outstanding rewards and value for our customers.

Boiler Service Experts, Welzig Heating and Air

If you’d like to improve comfort, air quality, energy efficiency and control over your home or commercial space, give us a call at (720) 336-3777. Welzig Heating and Air provides a complete range of boiler services, including installation of industry-leading innovations, meticulous seasonal maintenance and skilled repairs. We listen to concerns, find the best ways to optimize boiler performance and complete all jobs to satisfaction.

Satisfied Customers
They Speak For Us

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.


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!


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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