Dating back to 1877, Louisville combines small-community appeal with economic opportunity.  Historic Downtown features 100 year old wooden buildings, a thriving art scene, unique shops, pubs, restaurants, live music every night of the week, and a true glimpse of American history and ingenuity.

Dependable HVAC professionals in Louisville, CO

Thirty-two miles of trails wind in and out of Louisville, offering hiking, biking, beautiful weather and gorgeous scenery. With Rocky Mountain National park less than an hour away, a multitude of popular ski resorts, and easy access to museums and wildlife sanctuaries, Louisville has come a long way from its coal-mining origins.  It’s no surprise Louisville has been recognized as one of the best places to live and raise a family.

Welzig Heating and Air handles all your heating & cooling needs throughout Louisville, CO!

As a family owned business, Welzig Heating and Air upholds a tradition of quality.  We provide home and business owners in Louisville with a trusted source for a full range of heating, cooling, air quality, and water heating services.  Whether you’re in need of new installation, equipment replacement, regular maintenance, or skilled repair, our fully licensed, factory-trained, and NATE-certified technicians are prepared for the job.  Contact us at (720) 336-3777 for superior and affordable service, anytime, 24/7. We’re always available to ensure unmatched value from your investment.

HVAC Installation in Longmont, CO | AC Installation Boulder, CO | Heating Repair Louisville, CO

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HVAC Installation, Furnace Maintenance, AC Installation, Heating Repair & HVAC Service Longmont, CO, Boulder, CO, Louisville, CO & Lafayette, CO

Heating Repair in Longmont, CO | HVAC Service Boulder, CO | HVAC Installation Louisville, CO

Air Conditioning RepairHVAC InstallationHeating RepairAC InstallationFurnace Maintenance ∴ Boulder, CO ∴ Lafayette, CO ∴ Louisville, CO

Satisfied Customers
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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.


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!

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