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 756 reviews

Interstate Heating Co., Inc.

4.9

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.

Anna Wipperfurth

20:24 27 Jun 25

Dylan was great! Fixed the AC in less than 30 minutes and didn’t try to upsell me beyond what I needed. Would absolutely recommend!

The games god Games among you

18:32 27 Jun 25

Suchart Thammahong

16:56 27 Jun 25

Great customer service and very punctual. I would recommend this company again.

MARTIN THOMAS

15:10 27 Jun 25

Great guy!!

Zacheaus Donahue

15:38 26 Jun 25

Karl Fritchen

23:08 25 Jun 25

We came back from out of town last night and our house was over 80 degrees. Jake came out this afternoon and changed the capacitor and recharged the system and we are back enjoying the cool home tonight! Jake was very courteous and explained everything to us very clearly. He was a pleasure to work with and the staff at the office was awesome squeezing us in today! Thanks!!!

Cathleen Esselstyn

20:39 25 Jun 25

My air conditioner broke during this extremely hot spell. Interstate came out in a timely manner. Dylan was on time, polite, knowledgable & explained services and options, and fixed the problem. I've been with Interstate Heating and Cooling for 28 years.

Marnie Omer

19:21 25 Jun 25

Chris was excellent. He was efficient and very tidy. Thank you Chris for getting our AC running effectively again!

Larry Brand

18:17 25 Jun 25

Jake is awesome to work with. He is very positive, persistent and methodical.

Scott Larson

19:54 24 Jun 25

6/24/25 ..The technician's/Pauly Scott, were excellent on the installation of the air-conditioner and explaining everything to me and assisting me with the control unit/Nest system. I'd recommend using Interstate since every time I've had technician's come to my home they have been excellent.Scott Larson

John Schwitz

16:02 24 Jun 25

Technician was very friendly and knowledgeable. Was very thorough and explained everything he was doing and showed me the results from all the tests he had done. I would recommend Interstate Heating to anyone needing service.

Mary W

14:03 24 Jun 25

Interstate Heating and Eric get 5 stars from us. My elderly mother's central air went out just before a heat wave. Eric was able to get a quote written same day, I signed it on a Saturday and by Monday morning the crew was installing the unit. 8 hours later the house was back to 72 degrees. The heat wave rages on and we already have the new unit. Great service and great crew. We are very pleased with the work done and recommend anyone work with Eric and Interstate Heating.

E.W.

12:39 24 Jun 25

Josh is the man! Our house is cool again. Couldn’t be happier with our service. Thank you!

Trisha Stahl

18:31 23 Jun 25

Jake was professional, kind and intelligent. Air conditioning went out during the hottest day and they fit us in same day. Had everything running again in less than a hour.

18:01 23 Jun 25

14:40 23 Jun 25

13:33 23 Jun 25

22:07 20 Jun 25

Tristan was my service technician and he did a wonderful job. I have the 2 year/4 inspection service package. Tristan was very professional and personable and explained everything that needed to be done to keep my somewhat old air conditioner running for the season. I highly recommend Interstate Heating Co., Inc.

Beatriz Cirera

14:10 20 Jun 25

RDR .Lepkowski

18:09 19 Jun 25

The service tech was very informative and thorough when servicing the air conditioner. Would recommend interstate for an install or service.

Douglas Jacobson

20:42 18 Jun 25

Scott Schumann

14:39 18 Jun 25

Cindi Vetter

15:09 17 Jun 25

Such friendly, competent, and hard working gentlemen! I’m so glad someone referred me to them. Will continue to use them for sure!

Gary Puestow

21:30 13 Jun 25

Patti Sprague

21:00 13 Jun 25

Eric was professional and he was quick and honest. Seeing that my furnace is 38 years old I'm sure it's time for a new one and that's exactly what he told me.

Rachel Detert

20:57 13 Jun 25

Great service, very professional. Maintenance program has excellent value and has found issues before they become larger problems and promptly fixed.

ecsdigital2112

15:51 13 Jun 25

Service guys were very helpful. The answered all my questions and explained every process that pertained to my situation.

jan mueller

17:55 12 Jun 25

Erich did a great job. Explained everything very conscientious, clean and efficient. Very knowledgeable about the product. Great job.

Robert Pierce

14:50 11 Jun 25

The kind of person I would like on my team Jash

Candice Feider

22:17 10 Jun 25

David Carpenter

17:11 09 Jun 25

Josh does a great job. Listens to concerns and addresses them in a systematic manner. He has serviced our HVAC more than once and would welcome him back.

Dean Oswald

22:48 06 Jun 25

Had equipment needed and did a thorough inspection and was very courteous.

Mike (Mike 'Nerds' Neldner)

21:02 05 Jun 25

First time customer, very impressed with the level of service, knowledge, and professionalism of Interstate's technicians. From the first phone call to get scheduled, and through the service call at our home, they were helpful, informative, and helped me get the feel for what we had for options on resolving our hvac needs.I'll be a returning customer, that's for certain. Keep up the great work!

Deborah Kravit

18:58 05 Jun 25

Very professional and knowledgeable technicians

Fred Kinateder

13:51 05 Jun 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.

Michael Honisch

21:16 04 Jun 25

Great job by all technicians we've met over the past year, after leaving our previous recently sold VERY long-term HVAC contractor

Holly Nelson

14:15 04 Jun 25

Interstate does a great job servicing all our needs. Highly recommend.

Raymond Riemersma

18:44 30 May 25

GreatHe did a good job

Mindy Lloyd-Noel

18:15 30 May 25

Eric is the best!!! I will specifically ask for him for all my services. He’s so nice, and knowledgeable! This business is lucky to have him.

Tom Adler

14:15 30 May 25

Both Tristan and Alberto were great! On time, conscientious and focused on service. Clearly explained what they were doing to do and what was found. Efficient.

john seipel

15:00 28 May 25

Tristen and Alberto were amazing Techs…informative and caring and happy…which is very rare these days so I believe it’s precious!!

Kevin Webb

20:39 27 May 25

Honest advice!

Michael Urban

16:43 23 May 25

Great professionalism and communication from Tristan and Alberto.

Harold Krueger

15:31 23 May 25

Chris was conscientious in performing his work and kindly instructed me in the programming of our new thermostat. I have engaged Interstate for years and will continue to do so.

Michael Clark

14:47 22 May 25

Technician was friendly and professional. Answered all my questions!

Cheryl Milbauer

18:26 21 May 25

I have been thoroughly impressed with each person I have worked with at Interstate - office, sales, techs - everyone is focused on fixing your problem and offering solutions. I recently pivoted away from a mini-split unit to an upgraded sensor to solve an issue I have been having. Would recommend Interstate to anyone looking to partner with a HVAC provider.

Michael Zimmer

16:55 19 May 25

Eric was highly knowledgeable, friendly and thoroughly answered all of our questions. Will use Interstate again

Mary Clayton

13:54 19 May 25

We decided to replace our AC unit as it was 28 yrs old. Never had a problem, but time was not on our side. We called Interstate and everything went very smoothly. Installed in just a few hours. They did a great job. Highly recommend. They have been our go to guys for over 20 yrs. Very respectful of our needs and property!

MaryBeth Haugen

01:38 17 May 25

David Misorski

17:59 15 May 25

Very professional and courteous service.

Gina Woida

23:46 14 May 25

Prompt, communicated arrival time, explained what they found and what they repaired. Very efficient, very friendly.

Joanne Feypel

00:39 14 May 25

I had this company come in to check and clean my air conditioner. Did a beautiful job . It was dirty due to construction in our subdivision. He let me know what to watch for in my furnace for future problems. When that happens I will call them back.

Ross Read

19:29 13 May 25

Mark Treadaway

13:22 12 May 25

Efficient, polite, and professional

Richard Bauch

17:12 09 May 25

Christopher Mertens

23:29 02 May 25

Great service, troubleshot through some unexpected problems and kept me informed the whole time with what options we had. Appreciate Josh's work with us!

Amy Krenke

16:20 02 May 25

Great service, great techs. Very happy working with Interstate.

Carol Hemmingsen-Scheller

13:01 01 May 25

Red Rose Dentistry

18:07 30 Apr 25

He was very efficient, helpful, knowledgeable and timely. Thank you!

Keith Redding

13:03 30 Apr 25

don mantz

19:44 29 Apr 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.

Thomas Weghorst

17:44 25 Apr 25

Great tech...explained everything very well and was very thorough.

Art Jaehnke

19:35 18 Apr 25

William Wright

18:14 18 Apr 25

Very receptive to our needs. Excellent work and very honest. They have the best service and personnel in the entire area.

Juliet Mock

09:45 18 Apr 25

Chris C was awesome! So very kind, and efficient. He explained things well and was very professional. Really appreciated the quick response to the online inquiry, ease of scheduling and professionalism of all the team members we had interactions with. We will definitely use their services again when needed.

John Warczak

01:55 15 Apr 25

Eric, Interstate's service tech, did an excellent job. He was personable, professional, efficient and clearly explained what was done.

Sanjay Singh

23:09 11 Apr 25

The team at Interstate at Sussex has been outstanding for all the 3 years that I have availed their services. From the initial phone experience for scheduling, contract information and upfront capabilities - to when they come over for emergency or scheduled maintenance. Thy will even call you to remind that your prepaid service is due!The technical staff is excellent. Josh has been exceptional in intelligent diagnostics, addressing your queries and going over your system meticulously to give reasonable solutions without pushing spares or replacements, when you know you don't need them!I would recommend them wholeheartedly for all planned service contracts as well as emergency needs.Kudos and keep it up!

Drew Hietpas

12:53 11 Apr 25

Wayne Bernhardt

19:08 10 Apr 25

Both guys were polite and did a good job. Thank you.Wayne Bernhardt

Joel Anders

13:17 10 Apr 25

Interstate did a great job after a lightning strike hit our house diagnosing the problem. Technician Eric returned timely with the needed parts and completed the job.

Ronald Troy

20:17 09 Apr 25

Ethan and Kevin already do a great job - very reliable, responsible, and knows the equipment.

Florence de Leon

03:26 08 Apr 25

Gregg Bergin

21:35 31 Mar 25

Josh my installer was great. He installed my new Carrier Thermostat in quick order, and explained everything in easy to understand directions. My new thermostat plays nice now with my Aprilaire whole house humidifier. The Carrier app seems to be pretty easy to understand as well.

Lori Talb

19:08 31 Mar 25

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“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.

“Josh is the best. No one works harder. Our house is old and there have been multiple add-on HVAC units along the way. It is complicated and we've had numerous issues along the way. He is great about informing us what is going on and working to resolve any problem.”

- Bryan H.

“Jake was out early and got our unit repaired on one of the hottest days of the year. He recommended a replacement unit as ours is over 30 years old. He'll be back to replace.”

- Mike B.