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 812 reviews

Interstate Heating Co., Inc.

4.9

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!

Alex 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.

gert

16:15 08 Aug 25

Excellent service and communication. Thorough. Resolved problems quickly. Very pleasant and friendly.

Christine Jahncke

22:09 07 Aug 25

Tristan did an excellent job diagnosing the worn out part in my air conditioner and went above and beyond to get the part replaced the same day. Thanks Tristan for all your hard work!

James O'Laughlin

21:46 07 Aug 25

Very professional, always a pleasure working with their team.

Paul DeYoung

15:29 06 Aug 25

Chip Losee

18:47 04 Aug 25

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

Steven P

15:28 04 Aug 25

Stephanie Chapman

05:40 03 Aug 25

Chris Carne was fabulous. He was very professional and knowledgable. He knew the product and taught us about new products as well. I would highly recommend Chris.Stephanie

Brian Riddle

01:45 02 Aug 25

Quickly found a time that fit my schedule. Received a call to see if the tech could come early. Very polite and professional. Found and fixed the air conditioner very quickly.

Jennifer Hirsch

14:14 31 Jul 25

Josh did a great job. He services our radiant floor

Elizabeth Noorlander

20:47 30 Jul 25

I’ve used Interstate for years. The whole team is super helpful and professional, prices are the best in the area. Dylan fixed the issue quickly and explained what was happening. I had to leave to pick up my son, and Dylan even took the time to ask if his car was ok.

Sheri McNabb

19:45 30 Jul 25

Very professional, courteous and efficient

Adam Schlichting

18:35 30 Jul 25

lana kuenzi

16:57 29 Jul 25

Showed up on time, very professional, courteous & clean

kim mangarelli

18:19 25 Jul 25

Pat Miller

17:58 25 Jul 25

Karen Barnes

20:43 24 Jul 25

Josh was able to answer a reoccurring message that I have received multiple times on my thermostat.

Fred Kinateder

19:45 24 Jul 25

Josh did a great job. I was very satisfied with the service. He also gave me some suggestions as to my options for repair or replacement.

Scott Morey

17:15 24 Jul 25

Quick response with a fast diagnosis and repair for my HVAC system.

Kristine Cherek

11:02 24 Jul 25

Interstate Heating is exceptional. Our technician Chris was very professional, proficient, and friendly. I highly recommend!

Jerry Kienast

18:29 23 Jul 25

Josh was an honest tech and did a great job! I would highly recommend.

John Krainer

17:43 23 Jul 25

Very professional and courteous.

Sa Gt

16:20 23 Jul 25

Our technician Chris was extremely knowledgeable and courteous!!!

Dan Mishich

14:26 23 Jul 25

We had the pleasure of working with Jake on short notice while preparing to sell our home. He quickly familiarized himself with our in-floor heating system, reviewed the setup for accuracy, and performed thorough thermal scans of the floor. His deep knowledge and clear communication helped put our buyers at ease and addressed all of their questions. While no repairs or service were ultimately needed, I wouldn’t hesitate to recommend Jake—his expertise in these complex systems is rare and incredibly valuable.

Robert Schmidt

01:14 22 Jul 25

debbie grannan

23:52 21 Jul 25

Chris was very friendly and knowledgeable, looked at the thermostat readings and knew right away what the problem was.Only took about 15 minutes

Jeff Katzer

21:54 21 Jul 25

The technician was on time and very helpful. Diagnosed and repaired issue within an hour. Will recommend company to others.

Michael Ford

14:32 21 Jul 25

Chris is helpful. Explains his findings in detail and is also courteous. We give him 5 stars!

Lucky An!erson

14:06 19 Jul 25

It took forever to finish the job. He was concerned about getting paid.

Lisa Cretens

20:03 18 Jul 25

Our experience with interstate heating is always top notch. Our tech was very informative.

Gregory Harris

19:42 18 Jul 25

My issue was a simple fix. The evaporator coil drain elbow was plugged causing the water tray to over flow and cause water to leak on top of the furnace and floor. What was exceptional about the service was the technician (Eric) took the time and showed me how to address the issue in the future on my own. He even took the time to take the evaporator panel off (3 screws) and explain how the system works and where the tray was. Eric’s care in teaching me was outstanding. Great customer service by Eric!

rick worzala

23:12 17 Jul 25

Amanda Hetzel

13:47 17 Jul 25

Amazing service! Technician was very polite and knowledgeable! Couldn't ask for better service!

The games god Games among you

13:38 17 Jul 25

New AC unit and furnace installed by a great crew.

Cindy Macaluso

20:44 16 Jul 25

Interstate came to the rescue almost immediately. Hopefully our house will be completely restored to a comfortable temperature by this evening. Dylan was very nice and answered all of our questions. Highly recommend this company. The woman that answered my initial call was very nice and helpful.

Pamela Probst

13:34 16 Jul 25

Eric was friendly, efficient, and professional. He explained what needed to be fixed and why while completing our check-up maintenance on our heating/cooling systems.

Francisco Quiroz

12:43 16 Jul 25

Erik did a great work with our AC Unit. He took the time to do what was a difficult job and our unit was like new when he finished. Thank you

Matthew Mascal

20:35 15 Jul 25

Lauren Roberts

19:56 15 Jul 25

Tristan was an excellent serviceman. The customer service at the office was always helpful, kind and polite. Highly recommend!

John Nosbisch

20:45 12 Jul 25

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!!!

Randy Will

16:40 11 Jul 25

Discovered my old thermostat control was inoperative. Called Interstate & got immediate response to my problem, had a tech at my home within 2.5 hours - on a Friday afternoon!!Excellent service & attitude from Jennifer, the dispatcher.Eric, the service tech, was considerate, knowledgeable, professional & patient.

David Smith

03:35 11 Jul 25

Great

Linda Froehlich

18:46 10 Jul 25

Josh did an A plus job. He was considerate & I have gratitude that he went & got the parts & finished the repair instead of coming back the next day. Excellent !

Dr Kory W.

17:54 10 Jul 25

Interstate Heating and my tech Josh, were awesome! I was scheduled for service right away when I called. Josh came to my house, diagnosed the problem and began to fix things. We had to order a part, but the part came in right when he said and he called back to schedule a return appt at my convenience. Interstate has very professional team members from the office to the field and their fees are fair. I would highly recommend 🙂

Docs Inn

16:15 10 Jul 25

Jitendra Baruah

16:12 10 Jul 25

Everything was excellent.Eric was a very sincere and able technichal person. He did a very good job.

Jane Johnson

22:31 09 Jul 25

Very quick response and helpful technician. I always try to get some extra information about my HVC system and he answered all my questions.

Jake Bisco

21:53 09 Jul 25

Came late and was and expensive service.

Lora Gierahn

16:13 09 Jul 25

Mark Jochman

18:22 08 Jul 25

Excellent service and very professional!

Mike Pilgrim

16:42 08 Jul 25

Dylan Diagnosed properly and without delay. 6 days down waiting on part without Followup from office coordinator. Jake the service manager came with parts and did an excellent job. Part was actually under warranty for AC but labor, refrigerant and misc parts not covered added approximately $1,750.00 my side of equation. I thought that was a little steep.

Robert Sarsfield

14:19 08 Jul 25

Fast , courteous, service. Dylan was very knowledgeable and my repair was completed quickly. My initial call was answered by a real person and all the information I was given was accurate. I was told someone would be there in the afternoon and Dylan notified me that he was on the way early in the afternoon. I would recommend them to all of my friends

mary rupnow

20:01 07 Jul 25

Tristan was wonderful. He came and made sure my air conditioning was fixed and running correctly. He was personable. Give him a raise

Mark Ornelas

12:42 04 Jul 25

Having no choice....because of the100 degree days....plus it was on a sunday.....double time..... Almost $800.00 dollars later for a relay. l started to feel sick.But like l said l had no choice. Even tho he was here for10 minutes. Plus double to come here and go back ...l thought that was a little out there. Like l said ....l had no choice

Grant Thekan

12:40 04 Jul 25

Outstanding service and expertise. Prompt, knowledgeable and helpful to diagnose and provide options on the spot.

Jeff Peterson

13:56 03 Jul 25

Josh is AMAZING! Great communication of what the issue is, and quickly shares basic upkeep suggestions. This is the second time we have had Josh as our Service person and I will always ask for him moving forward. I used to call him 5 Star Josh, but his new name is 10 Star Josh!!!

Michael Todd

20:43 02 Jul 25

July 2nd and no air conditioning! Eric just left and my unit is running again! Interstate Heating Company is an excellent provider of both service and replacement of heating and air conditioning equipment. I've used this company at my home and commercial building on a number of occasions. They put a new furnace in my duplex this past winter. Always top notch people, timely service and reasonable pricing. I recommended Interstate to a friend whose commercial building lost heat while he was out of state. Interstate came right out and got his heat back on. That's a great company!Mike Todd Okauchee LakeMilwaukee Lawn Sprinkler Corp

Jyotsna Bharatkumar

19:53 02 Jul 25

The maintenance and repairs were done and reasonable explanation as to the parts failure. Satisfactory service

Dan N

17:13 02 Jul 25

Quick diagnosis and repair

Tom Sisk

16:38 02 Jul 25

Dylan was efficient and fixed the issue.

Ronald Roberts

23:09 01 Jul 25

Several attempts were made to cancel this appointment. The technician came anyway, went on the roof without authorization, and was asked again to call me.The technician failed to call and proceeded to do work. The technician then sent an absurd bill. He proceeded despite evidence that work had started.Beware of this contractor!

John LaBonte

19:37 01 Jul 25

Pam Johnson

17:48 01 Jul 25

I was able to get an Interstate AC tech. to my home quickly on a hot summer today to repair my AC system that had broken down. The technician appears to have taken care of problem, was prompt and courteous.

Dori Walk

01:24 01 Jul 25

Tristan from Interstate Heating and Cooling was outstanding!

Eric Grismer

14:10 30 Jun 25

Technician was here on time with preceding call to advise on way. Went through all checks. Found failing compressor motor Cap out of spec. He advised of failure implications and costs. Had part and replaced. Advised all other functions were in spec. Unit was a Carrier system put in 2006. 19 years old and looking good.

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“Eric O. did the maintenance on our furnace and AC today. He did a super great job, was very professional, kind and efficient. We are very happy that we have purchased our products through Interstate and that your company does our yeasty maintenance on both items. Things always go very smoothly.”

- Arlene H.

“We are very satisfied with the repair. Chris was very friendly and knowledgeable.”

- David F.

“Dylan provided excellent service early on a Saturday morning. On the initial phone call, he was clear in providing a perspective on costs associated with an emergency service call which I very much appreciated.. He showed up promptly and he quickly diagnosed we had a faulty part. After a few minutes, the part was replaced and cool air was flowing. Dylan was pleasant, professional, and competent in provide excellent service for us. Thanks!”

- Jim K.