SOUTHEAST WISCONSIN’S HVAC EXPERTS

ESTABLISHED IN 1962

OUR STORY

Continuing a Tradition of Exceptional Heating and Cooling Services

What began in a garage in 1962—with Gordy and John Cole’s commitment to offering honest, high quality HVAC service—continues today at Interstate Heating Co. in Sussex. We’ve grown to offer the latest heating, cooling, and air quality products, and our service area now covers all of southeastern Wisconsin.

We are three generations strong and still follow the most basic rule of business: we treat our customers the way we want to be treated.

About Us

WHAT OUR CUSTOMERS ARE SAYING

Google Rating

4.9

Based on 884 reviews

Interstate Heating Co., Inc.

4.9

John Bogues

16:14 15 Dec 25

Great workFriendly technicianFair price

Kurt Farrell

13:56 14 Dec 25

Our boiler went out on one of the coldest days yet in 2025. I called Interstate Heating because they were a dealer for Buterus, the brand of boiler that we were using. I promptly received a call back from Tristan Garland who was on-call for the weekend who professional and courteous. We walked through a few diagnostics and Tristan quickly came to the conclusion the the ignitor was probably the culprit for the boiler not starting up. Within the hour Tristan has procured the parts from his shop and was at our house installing the parts. Within 30 minutes all was back up and running and we had heat!He was professional and I would recommend him and Interstate for all your HVAC needs.Thanks Tristan!

Brent DesRoches

13:41 13 Dec 25

Interstate Heating replaced our 21 year old furnace and a/c with a Carrier cold climate heat pump and high efficiency gas furnace. I worked with Tom from sales to get a good balance of price and efficient equipment. He did a great job working through different options to show different price points. The install crew also did a great job. They laid down drop cloths to protect the wood floor and carpeting and they cleaned up well after the work was complete. The equipment installation and duct modifications look very well put together.

Ruth Hau

12:01 13 Dec 25

Great job, Scott was on time and very professional.

Lisa kuehn

21:48 11 Dec 25

Karen Wright

14:44 11 Dec 25

I trust Interstate Heating. We have used them for27 years

Jim Sawyer

23:06 10 Dec 25

Tristan was able to explain exactly what was needed and provided a very thorough service of our furnace. I would highly recommend them and will continue to use them for our Hvac system.

James Long

21:30 10 Dec 25

Courtesy, knowledgeable, explained what he was going to do and reviewed with me what he did

Cynthia Pares

16:36 10 Dec 25

Eric is wonderful!

J W

23:55 09 Dec 25

Tristan was highly knowledgeable and courteous. Possesses a high skill level, superior troubleshooting abilities and checked multiple system functions with various diagnostic tools. Went above and beyond to make sure everything was running properly. Great customer service throughout too.

LBRC Account

22:40 09 Dec 25

The service and knowledge Trinstan shares is second to none. Very professional. Highly recommended.

mark waraksa

20:58 09 Dec 25

Nice gentlemen came to help me on the thermostat

Jim Wollin

20:53 09 Dec 25

Excellent service knowledgeable polite, service done in timely fashion. Would recommend him and his partner

Steven Burbach

15:22 08 Dec 25

Susan Eng

00:30 06 Dec 25

The pro did an excellent job of diagnosing the problem with my furnace.Im not happy with the warranty on the furnace, the furnace is only a little over one year old and the Carrier warranty only covered the cost of parts and not the labor which was $489.55! It seems a warranty should be better than this for a relatively new furnace. Also it seems that the problem with the furnace is one that occurs frequently and may occur again. It seems to me that the thermostat recommended by your company from the furnace company has more issues than my Nest thermostat which governs my other furnace just fine. If I require further service, i think changing the thermostat seems to be a better plan!

Chip Losee

20:26 05 Dec 25

Very satisfied, Tristan was awesome. Very professional and knowledgeable.

Amy De La Cerda

20:04 05 Dec 25

Interstate was amazing. From the empathy and friendly manner my initial call was handled, to the thorough way Eric explained what was happening, to our install, everyone was super polite, respectful, and did great job. Victor and his partner for the install laid down tarps and wore shoe covers to keep the pathway clean and even took extra steps to clean up the rust stains on the floor from the old unit. They also took the time to help us get familiar with our new thermostat.

Diane Zore

17:55 05 Dec 25

Tristan was here and fixed the issue, was professional and competent. We have been customers for over 25 years and rely on your company to always do your best!

Joseph Otu

02:10 05 Dec 25

Eric was very knowledgeable, detailed, and professional. He explained what was wrong and what he did. I was very pleased.

Kathleen Dubiel

02:04 05 Dec 25

All was pleasant. I did pay cash and without receiving a receipt felt odd but was sent the reciept via email!

Sally Fritz

21:29 04 Dec 25

We’re very grateful that the 2 gentlemen pursued the problem since of course when they got here the furnace appeared fine! They found a large birds nest in the intake pipe!Very happy with their service!

18:04 04 Dec 25

15:15 04 Dec 25

23:13 03 Dec 25

15:45 03 Dec 25

22:35 02 Dec 25

Austin was courteous and professional

Susan Masche

20:40 02 Dec 25

Clean unit now without dead baby mice. No problem with unit found.

Henry J Klein

19:39 02 Dec 25

Maggie Schroeder

14:33 02 Dec 25

Very prompt, explained everything.Trust them.

Terry Flanagan

23:56 26 Nov 25

Our service technician was very detailed oriented and kept us informed at every step of what he was doing and his findings. Excellent service !

Bob Kachelek

01:30 26 Nov 25

Very friendly, explained everything he was doing. Knowledgeable and gave us good maintenance tips on our furnace and AC.

Gerardo Caballero

17:55 25 Nov 25

John Beauchamp

00:20 25 Nov 25

Eric did an excellent job in diagnosing and repairing the HVAC unit. Thank you for the great service!

Nicole Smith

22:03 24 Nov 25

Tyler was very knowledgeable and polite when doing regular maintenance on my furnace today. Great job!

Melissa Murray

21:35 22 Nov 25

Tristan was professional, courteous, efficient, and honest. He explained things to me in terms that were easy to understand and did not try to sell me things that I didn’t need. I would welcome him in my home again to service our heating and cooling system.

Julie T-V

20:32 21 Nov 25

They were neat, on time and fantastic to work with!

Carlene Wade

13:19 21 Nov 25

Great customer service!! Antonio was very professional and they did an awesome job. Cleaned up very well after they finished. We are very pleased!!

mary muntner

22:05 19 Nov 25

Trysten was very professional and knowledgeable. He was very pleasant and obliging. I would certainly like to have him do the work I have when i am ready. He is definitely an asset to Interstate.

Geri Gerschke

18:50 14 Nov 25

These guys are SO helpful and efficient and respectful.

anthony corrao

16:58 14 Nov 25

Tristin was very thorough and professional!

Christine Jahncke

15:32 14 Nov 25

Josh did an excellent job diagnosing the worn out part on my furnace and was great communicating with me during the repair. Thanks Josh for all your hard work and for making my home nice and warm again!

William Talbot

16:08 13 Nov 25

Wayne & Mary Jo Koch

00:48 13 Nov 25

Josh did his always excellent job on our biennial furnace check up.

Jeff Allen

23:42 12 Nov 25

Claudia Bechthold

18:19 12 Nov 25

Dave Goss

19:57 10 Nov 25

Josh from Interstate Heating did a very thorough job of investigating why our furnace stopped working in the middle of the night. He did have to order a new part and will return tomorrow afternoon to install it.He checked a number of things on the furnace to make sure everything was working correctly!

Leon Saryan

18:40 10 Nov 25

Efficient

Michael Cieslewicz

21:30 07 Nov 25

Dylan has provided service to us one previous time. He is always courteous, efficient and knowledgeable.

Craig Hurst

19:58 07 Nov 25

Interstate has been servicing our HVAC for several years. The technicians are always courteous and professional.

michael phillips

17:44 07 Nov 25

very polite and was able to correct our condensate pump problem

Thomas Gerger

14:21 07 Nov 25

Tristan was great!! Very personable and qualified. Answered all my questions too! Tom Gerger

Amy Kuhnau

16:36 06 Nov 25

Kath Swanson

23:41 04 Nov 25

Josh is an excellent technician. He is prompt, polite, competent, and explains the services and/ or fixes clearly.

don mantz

15:04 04 Nov 25

Eric Osterman is always a pleasure to work with. He knows the heating business and communicates well. He completes the project in a professional manner and reviews what he did with us. Top member of your team.

gwen medved

19:34 03 Nov 25

Justin was great! We have worked w Interstate for multiple properties for over 20 years. Per usual, great service, very informative, did HVAC maintenance, replaced filter, checked C02 levels and checked my equipment on main floor as well. Looking forward to my UV light, air purification and dehumidifier being installed next week!

Leonard Lutzke

20:02 31 Oct 25

Techs know their business well.

Jim Quinlan

14:45 31 Oct 25

Job completed quickly and professionally

Harry Clayton

19:53 30 Oct 25

On-time and worked clean and efficiently.The garage heater Turned out better than I anticipated!

John Heinrich

23:05 29 Oct 25

Debra Dixon

23:28 28 Oct 25

Good experience, gave good instructions and advice.

Greg Lutz

20:53 28 Oct 25

Josh is amazing. He is always able to figure out what is going on and I never feel like he is trying to sell me something I don’t need. It’s great to have that trust and confidence. And, he is a really good man who cares.

Katie Knudsen

14:09 28 Oct 25

Excellent service. On time with great communication on arrival time. In addition to annual furnace maintenance - a humidifier was added. I was very happy with the installation!

David Smith

21:55 27 Oct 25

Great

Joan Gertel

16:41 26 Oct 25

Kevin gets five stars

The Commish

15:19 23 Oct 25

They were fast to respond and schedule. The technician was very knowledgeable, helpful, and provided great details and recommendations. Overall price seemed a bit high but not outrageous. Will definitely do business with them again.

Sandy Jere

15:15 23 Oct 25

Peter Peterson

18:37 22 Oct 25

Chris did a wonderful job. With his kmowledge we trusted his recommendation as to what was needed.

David Felder

18:00 21 Oct 25

Dylan, was very professional. Tried to break the cost of the new part gently to me. But over $1, 500.00 is a hard number to swallow for a 11 year old furnace. I think carrier is off of my list for my next furnace and AC.

Dan Roskopf

23:20 20 Oct 25

Kristin Troy

00:04 18 Oct 25

They came to fix a blower on the furnace which was unhooked by one of their employees during their routine maintenance appt. They hooked it up and charged us for a visit. Poor business practice.

Robert Gagliano

23:49 17 Oct 25

Dylan came to service our furnace and was on time, very professional & answered all of our questions and very informative and knowledgeable about the furnace and the issues. It was really a good experience. We will request him in the future. Our thanks also to Jake the Service Mgr.,along with Ellen & Jessica in the office. All very helpful. Great experience.

Robert

15:22 17 Oct 25

Excellent service and support, I will request Dylan for all of my services

Samantha Plotz

23:30 16 Oct 25

Nice, personal technicians.

Thomas Spleas

14:11 16 Oct 25

STEVE FRANCAVIGLIA

00:21 16 Oct 25

Eric was professional, knowledgeable, informative and talk time to teach.

Cedric Mays

19:46 15 Oct 25

Great service.

Alicia Cooper

12:09 13 Oct 25

Jeana Holt

19:53 07 Oct 25

Tristen did a phenomenal job communicating with my husband and I throughout the HVAC system maintenance visit. He ensured that we both understood the implication of his recommendations and potential cost if/when we choose to have something repaired. I HIGHLY recommend Interstate Heating Co., there service always exceeds my expectations.

Aaron Holt

19:10 07 Oct 25

Tristan was awesome. Timely, thorough and great communication throughout!

Dennis Shebesta

15:45 07 Oct 25

Chris was the best guy we’ve had here from interstate in the last 25 years. Five star plus

William J Radler

10:59 05 Oct 25

Rod Myers

19:59 02 Oct 25

Friendly and efficient

James Spangler

19:07 02 Oct 25

He did a good job. Give him a raise.

Judy Stagl

18:26 02 Oct 25

David Beilfuss

17:02 02 Oct 25

John did a great job!

Karen Chamberlain

18:52 30 Sep 25

Excellent service. Knowledgeable and caring serviceman!!

Ronald Motley

11:15 30 Sep 25

Called Interstate on 9/24 for an estimate on a whole house humidifier replacement and an attic fan problem. They said they would email me an estimate. It’s 9/30 and not a peep. No follow-up from customer service to check on the quote status.Shows lack of respect for customers and poor internal processes.

Laura Staton

21:59 29 Sep 25

Dylan was great! Timely and very efficient. Thank you for your quick and friendly service!

John Nosbisch

13:40 28 Sep 25

Fall Update: Eric was back for our heating maintenance. He discovered a wearing component which would shut the system down due to safety. No one wants to be cold in January. Eric quickly replaced it avoiding a winter emergency service call. Great job Eric!Eric Osterman was recently to our home for our annual A/C system preventative maintenance. He was very professional, thorough and answered my questions in a manner I found easy to understand. The good news was Eric discovered and quickly replaced a key component in the outside compressor that would have eventually failed preventing the home from being cooled. That is the value of their preventative maintenance program. Thanks Eric!!!

Wes Breeden

20:53 26 Sep 25

The entire experience was very well completed, and I believed the pricing was extremely fair. Also, thanks to classic homes for the recommendation.

Bridget Post

19:59 26 Sep 25

Dylan was great and very knowledgeable!!

Jeff Guidinger

16:19 24 Sep 25

Laurie Kempke

16:34 23 Sep 25

The technician was polite and friendly. He explained the process and results. Would recommend to my friends.

Jocelyn Irvine

19:11 22 Sep 25

Casey A. was extremely professional, but also very personable. Will hire them again!

Scott Lucas

17:17 22 Sep 25

Thorough, professional work

Susan Gebauer

17:08 22 Sep 25

Bill Paquin

21:23 20 Sep 25

Great tech. Friendly and helpful

Kyle Behrens

22:46 17 Sep 25

Randy Moll

19:39 17 Sep 25

Service technician Tristan was on time, professional, and courteous. He did his job quickly and accurately. He detailed the work he performed, and cleaned up afterwards. I have used Interstate for many years ,and would recommend them to anyone needing this service.

Susan Yokosh

18:02 17 Sep 25

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