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 854 reviews

Interstate Heating Co., Inc.

4.9

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!

Carlene Wade

21:26 13 Nov 25

Great customer service!! Any questions I had they were answered. The technician Josh was very nice. I really appreciate a reliable company as yours.

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

Karen Wright

21:29 09 Oct 25

I trust Interstate Heating. We have used them for27 years

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

Michael Urban

22:44 12 Sep 25

Josh and Tristan did a great job of diagnosing our problem, communicating what needed to be done, and then providing the fix. We received outstanding same day service.

LINDA KAUTZ

00:16 12 Sep 25

Showed promptly. Checked various components and operations. Answered questions. He was very professional.

Edward Raether

12:58 11 Sep 25

Prompt response and excellent installation of new furnace

Peter Beardsley

01:00 10 Sep 25

Peter Diotte

18:18 09 Sep 25

Eric was the service tech - total pro - on time and performed the annual maintenance on the heating and A/C systems. We talked about upgrading existing thermostats to WiFi ones and he had the desired models onboard. In addition, we talked about a possible future garage heating unit install and talked me through it. I would rate service as Excellent.

Ildiko Huppertz

17:36 09 Sep 25

Chris was the ultimate professional. He repairs the miss wiring of another technician preventing me from having to replace my furnace. I am grateful for his honesty and service and now a future customer going forward. Interstate came highly recommended and it was spot on. Service call cost is the most reasonable of any other vendors.

Mary Jo Dempsey

15:11 08 Sep 25

David Schieszler

19:52 05 Sep 25

Good crews, fair price, timely installation of a new boiler. Happy with the service provided.

Debbi Triplett

14:03 04 Sep 25

Mark Treadaway

18:08 03 Sep 25

Prompt, clean, very professional. Explained what they were checking and what they found.

Mark Treadaway

18:05 03 Sep 25

Efficient, polite, and professional

Fred & Jane Lawler

18:00 03 Sep 25

Guys we’re very professional

Ms. Basquet

16:33 03 Sep 25

Texted before arriving. Very polite and professional. Explained everything. Both guys were very nice and respectful. Very happy with them.

Jonathan Dake

23:13 02 Sep 25

Suri Venkatraman

19:35 28 Aug 25

Joey Bohlmann

19:02 27 Aug 25

Good communication-explained everything well, efficient and thorough.

Lori Papa

12:49 26 Aug 25

Tristan and Joe were on time, very professional and informative.

Tony losiniecki

19:01 25 Aug 25

Chris is honest, professional and knowledgeable. Quick diagnosis of the issue. I highly recommend Interstate Service!

Jerome Pitts

14:16 25 Aug 25

A fine young man. Very knowledgeable.

Jerome Pitts

20:18 22 Aug 25

Josh did a fine job. Confirmed system is operating correctly. Will probably sign on with Interstate maintenance program.

Jennifer Johnson

20:12 22 Aug 25

Melanie Bond

13:09 21 Aug 25

Tom Konkol

03:35 21 Aug 25

Josh was first class in every way. Helpful and to the point. I recommend him to anyone. Amen.

TOM KANTER

01:23 21 Aug 25

ExcellantKNOWLEDGABLE AND FRIENDLY

Joel Anthony

22:32 20 Aug 25

Dylan did a great job reassuring us that our furnace was in fine working order after a sub pump failure5 stars!

Andy Murphy

19:56 20 Aug 25

Knowledgeable and efficient.

Michelle O.

19:44 19 Aug 25

Dean Maytag

19:10 14 Aug 25

Excellent, the tech, Dylan, was very helpful and knowledgeable. Mask and booties much appreciated

Curt Nash

18:04 14 Aug 25

Brent Boettcher

14:31 14 Aug 25

Bruce Seefeldt

17:47 13 Aug 25

Tristian the technician was great, he diagnosed the problem, gave me options and completed the repair. He was very professional, friendly and kept me updated at all times.

Cindy Schaus

17:36 13 Aug 25

Josh is a careful professional that makes it all work!

Michael Reinders

12:08 13 Aug 25

Tristan came out to get our A/C back up and running. He went through the troubleshooting and kept me informed all along the way (I appreciate that!). He found the communication (wiring) between the two units was bad and ran a temp wire to make sure. Thankfully, the system started up. Then, he moved the wire to a safer location until someone else can come out and re-wire professionally.No issues! Tristan was very easy to work with and would recommend he come out for our next visit.Highly recommended! It was a pleasure doing business with Interstate again.

Brad Brogan

00:07 13 Aug 25

John Beauchamp

18:42 12 Aug 25

Tristan did an excellent job in diagnosing and repairing the air conditioner unit. Thank you for the great service!

kpbDO kpbDO

13:57 09 Aug 25

Great experience as always. The team was friendly, skilled and hard working. Always a pleasure working with Interstate from the scheduling to the HVAC team.

See all reviews Write a review

“Installation was quick, clean and efficient”

- Angela P.

“Great customer service!! The technician Josh was awesome! He was very informative and answered all of my questions.”

- Carlene W.

“Chris Carne was the technician who came to our condo today to repair and service our gas furnace. He did a very thorough testing of the furnace and discovered we had a faulty gas valve. His courteous explanation of what he was doing along with his nice personality made this repair a pleasant experience. We would highly recommend him for any of your service issues.”

- Alan R.