About Us

brennanwebsize (32 of 68)

Our Approach

We are known for our high quality workmanship, reliability, and personal attention to each customer's job.  All owners are involved in their projects from beginning to end, in both the design and installation phases.

Our Story

Brennan Heating and Cooling was established in June of 1990 by Billy Brennan.  Billy's tw

o brothers, Dave and Pat joined Billy in the early 1990's.

Bill Brennan, father of the three brothers, started B&B Heating in February 1977 passing down the sheet metal tradition.

Billy earned his Associated Mechanical Engineering Degree from Northern Havre in 1978 and an HVAC Design Certificate from Dunwoody Institute in Minneapolis, MN in 1980.

Dave graduated from Montana State University in 1987 with a Mechanical Engineering Degree.

Pat's degree was in Mechanical Engineering Technology also from Montana State University in 1991.

Meet the Team

Billy, Dave and Pat Brennan are the Officers and Owners of Brennan Heating and Cooling Inc.  Each one is involved in the community and loves being active and in the outdoors when not working on the various business aspects of running a busy company.

Bill Sr. and Billy Brennan

Founder & President


Bill Sr. with his son Billy (20th) Anniversary of Brennan Heating.  Billy works more with the Commercial side of the business doing design, estimating and installation.

David Brennan

Owner and Corporate Officer


David Brennan works primarily with the Residential side of the business including design, estimating and installation.


Pat Brennan (left) on the jobsite

Owner and Corporate Officer


Patrick Brennan works with both the Commercial and Residential sides of the business including estimating and installation.


Call for more information

Let us know how we can help you with your project.

Call (406) 452-1133