About Thielmann & Son Heating and Cooling

Offering Reliable Heating & Cooling in Wisconsin for Over 90 Years

In 1929, John Thielmann founded the family business, servicing boilers and oil furnaces. His son Walter soon joined forces with him, building the business into what it is today. Together, John and Walter became the local representatives of the Lennox Furnace Company. The family tradition continued with Walter’s sons, Paul and Tom, who started working in the shop when they were still in grade school. Paul took over the business in 1969 and introduced air conditioning. Tom rejoined the business as a service technician in 1977 and then continued to serve as the company’s office manager and service technician. We still take extreme pride in continuing the Thielmann name and great service that Thielmann & Son has been known for throughout the years.

"With offices in New Berlin, Hartford, Burlington, and Menomonee Falls we provide exceptional service to residential and commercial clients"

Thielmann & Son is proud to be your heating and cooling experts in Southeast Wisconsin since 1929! With locations in New Berlin, Hartford, Burlington, and Menomonee Falls we provide exceptional service to residential and commercial customers across all of southeast, WI. When you turn to Thielmann & Son for your furnace repair, air conditioner repair, or the installation of new equipment, you will have the peace of mind knowing that we have spent over 90 years making homes comfortable. Thielmann & Son provides all your heating and cooling needs, as well as air quality systems, sheet metal services, and repair of all makes and models of heating and cooling units. Generations of loyal customers turn to Thielmann & Son for quality products and expertly performed installations. Let the experienced professionals at Thielmann & Son put their years of expertise to work for you. We have an A+ rating with the Better Business Bureau and have hundreds of satisfied customers and outstanding reviews on websites such as Angie’s List, Yelp, Google, Lennox and more.


At Thielmann & Son we care about the communities that we serve. We are members of the Chamber of Commerce in many of our communities. We support charities such as Girl Scouts, Disabled American Veterans, Special Olympics of Wisconsin, Multiple Sclerosis Society, and the American Cancer Society. Thielmann & Son proudly participated in the Extreme Makeover Home Edition home build that was done in Dundee, Wisconsin. In addition we also help local charities such as Lions Clubs, Knights of Columbus, as well as many local youth sports teams and local Police and Fire Department special programs.

Thielmann & Son also gives back in another big way. We have participated in the Heat UP Wisconsin Program since its inception. Heat UP Wisconsin is a program that was developed by Lennox Dealers in Wisconsin and Upper Michigan. Every year Lennox Industries and participating dealers donate and install a new Lennox furnace for families in need throughout Wisconsin and Upper Michigan. Thielmann & Son donates all of the additional materials needed for the installation of the new furnace and the employees of Thielmann & Son donate their time. Through this program we have been able to help families that could not otherwise afford to replace their heating equipment. Some of these families had already been without heat in their home for two years. To read more about this program or to nominate a deserving family please go to www.heatupwisconsin.com.

Meet Our Amazing Team