SOUTHEAST WISCONSIN’S HVAC EXPERTS

ESTABLISHED IN 1962

Schedule Service

SOUTHEAST WISCONSIN’S HVAC EXPERTS

ESTABLISHED IN 1962

Schedule Service

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 935 reviews

Interstate Heating Co., Inc.

4.9

Greg Farnham

14:36 24 Feb 26

Josh was on time for the service call; pleasant to work with; diagnosed and assessed the problem, and had the parts and equipment to solve the problem.

Greg Burek

23:19 23 Feb 26

Terry Flanagan

15:31 20 Feb 26

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

Murthy Mantha

18:30 19 Feb 26

The technicians were hard working honest and knowledgeableI would recommend them to anyone

Greg Lutz

00:00 17 Feb 26

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.

John Arth

21:19 16 Feb 26

Michael Smith

02:23 11 Feb 26

Technician was very helpful and knew what he was doing. Replaced several parts on the furnace under warranty

Jerry Weidmann

01:18 11 Feb 26

We have two furnaces and two air conditioners from Interstate. Our heat in one portion of our house was not working well. A tech from Interstate analyzed the situation, provided two alternatives, and after we selected a strategy Chris Carne came and updated the system within two business days and it works perfectly.

Mary Latz

19:32 09 Feb 26

Had a small furnace installed to heat our recreation room. Antonio and his assistant were very professional! Interstate Heating has installed all our furnaces and air conditioners for the past 50+ years and have always done a good job,

Patty

00:03 08 Feb 26

We have been customers of Interstate for 30 years--these guys are good! Their tech, Chris, is great...good at troubleshooting and always shows up in a positive mood and ready to tackle whatever the issue is. Whether regular maintenance or a problem to solve we always know Chris will take care of it. Highly recommend!

Andrea Munoz

17:44 06 Feb 26

James Dewar

00:53 06 Feb 26

phil keener

20:11 04 Feb 26

Explained well, what could have been causing problem, and suggested several possible steps to resolve it.

John Mangold

22:51 02 Feb 26

Eric did a complete checkup and identified the issues in a timely fashion. Would recommend Eric and the company for any other needed repairs or purchasers.

Bill Hansen

19:21 02 Feb 26

Technician was on time and thorough. Very bright and articulate. A great ambassador to your organization. Thank you Tristen!

Kurt Anderson

18:37 02 Feb 26

Timely and reasonable.

Jennifer Thompson

15:32 02 Feb 26

Lori Burke

14:56 01 Feb 26

Jagjit Kaur

21:44 30 Jan 26

I have seen a steady decline in Interstate Heating Sussex WI since Tom the old owner sold the company.My home project took nearly five years to complete. Throughout this period, delays were repeatedly blamed on ownership changes, COVID, part unavailability, missing components, and the use of non standard parts that Tom’s company decided to use.Despite paying over $60,000, my home project was never properly finished. I was eventually pressured to settle with unfinished work. After that, I was informed that there were no warranties covering the work performed.Key issues I experienced:• Poor and incomplete finishing• Warranties were never registered, and I was never informed that failure to register them directly with Carrier would reduce the warranty period by half• Use of non-standard parts• Rude and unprofessional email communication from employees• Consistent lack of communication• Noticeable change in employee attitude after payment was made• Voicemails and emails frequently ignoredIn the end, I had to hire another company to correct and complete the work that was originally paid for.This is the first time I have ever written a public review, but the experience left me no choice. I have shared detailed reviews on YouTube, the BBB, and with consumer protection agencies so others can make an informed decision.

R M

22:23 29 Jan 26

We had a new furnace with a bad gasket, causing water to leak beneath the unit, and rust inside it as well. Tristan was courteous, helpful, prompt, and friendly. We could tell that he cared a lot about getting the job done right, and he patiently answered all our questions. Great service and great technician.

Brett M

19:19 27 Jan 26

Emergency call for no heat was responded to Very Quickly. Thank you Ellen.

Gary McMurray

19:54 26 Jan 26

Very knowledgeable and exhibited a true understanding of the problem.

Thomas Gerger

18:38 26 Jan 26

Tristan was great!! Very personable and qualified. Answered all my questions too! Tom Gerger. That was Nov. 2025. Now today, Jan. 26,2026, Eric O. came to analyze a major problem with our furnace. Eric originally installed our Carrier system for us in 2007! He's extremely thorough and friendly. Turns out a new furnace makes a lot more sense than putting money into the old one. Very thrilled that Interstate will install the new unit tomorrow morning. Our fireplaces and electric space heaters have been running since late Saturday morning! Tom Gerger

James O'Laughlin

16:31 26 Jan 26

As the weather has been extremely cold -20's and -30's, all HVAC contractors are swamped. The Interstate Heating team has the man power to adapt to any situation. Very professional, on time and always a pleasure working with their team.Jim

Jill Sweitzer

15:45 26 Jan 26

Mark

13:48 26 Jan 26

The men who came out were wonderful, courteous, professional, explained things, and were polite. They did a great job!The cost was unbelievable. We paid $600 for a person to come out here just to tell us we needed a new furnace. That is outrageous!And the emergency service is hardly that at all. Your store/shop did not have the part we needed to fix the furnace long enough for us to be warm until the next day when the furnace could be replaced. So we did the best we could to stay warm and were without heat from 5pm to 8am the next day. But we paid for a service that basically doesn’t exist.This is no reflection on the three men who came out. It is an evaluation of the company policy or lack thereof. These three people were the only reason we continued with you.I’m highly disappointed. But kudos to the three who were here.Dr. Mark Amundsen

John Williams

13:20 24 Jan 26

Todd Mueller

00:52 24 Jan 26

Our furnace stopped working and they sent their technician. He found out that the gas value was bad and he replaced it. It worked. We were very satisfied.

Jeff Lombardi

22:36 23 Jan 26

Very competent and professional Technician - Dylan. He was courteous, professional and diligent while diagnosing a furnace issue at my home. Albeit, he gave me bad news that I needed a replacement he provided options and solutions to my problem.Very professional staff from my initial phone call to the visit and estimate.I highly recommend this professional HVAC business for your personal needs.Jeff

Neil W Holaday

19:30 23 Jan 26

The technician was great and very knowledgeable. Everything went well.

Brittney

18:24 23 Jan 26

Keith Nettesheim

17:39 23 Jan 26

Very helpful and explained everything in great detail. Thank you!Keith

Michael Schneider

18:52 22 Jan 26

Very good service tech, explained the details of the heating system functions. Very fast and knowledgeable. He even fixed a wiring error from original installation. Highly recommend.

Kenneth Romeis

15:13 22 Jan 26

Dylan showed up on time and ready to work. Excellent customer interface and patience. I had questions and Dylan had answers. He took the time to answer all my questions. Not only was he knowledgeable, he is a genuinely nice and sincere person.

james jarrett

05:05 22 Jan 26

Eric was very professional and he knew just what he needed to do and did it very well and since I was a electrical contractor for many years he would be the type of person that I would want working for me

Bob Mikulec

22:43 21 Jan 26

My Interstate Heating technician, Tristan, did a great job and answered all my questions about maintenance, condition and age of equipment, and operation of my smart thermostat.

dana gilboy

21:44 20 Jan 26

Great service from Interstate! Tristan performed standard furnace check and maintenance. Very professional and informative.

Brett Erickson

22:39 19 Jan 26

Johannes Schulze Vohren

21:51 19 Jan 26

The service technician was very friendly, answered all my questions and made good recommendations.

Carrie Jaskaniec

13:50 17 Jan 26

Tristan was on time, friendly, helpful, cleaned up when finished and I would highly recommend him as a technician!

Thomas Nienow

16:39 16 Jan 26

Joseph Bingen

21:21 15 Jan 26

Dillon was prompt, courteous and worked at correcting thingd

Patti Sprague

18:38 15 Jan 26

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.

Tara Salaks

15:04 15 Jan 26

Very fast and great customer service. Chris is great!

G Schmeling

20:41 14 Jan 26

Highly recommend. Have used them for 30+ years

Tom Gruenke

12:38 14 Jan 26

00:59 14 Jan 26

Tristan did a thorough job maintaining my furnace. During the routine maintenance, he discovered an issue with the furnace inducer motor (bad bearing) and worked with me to file the warranty claim. Thanks for the great service, Tristan! Now my furnace is running in tip top shape again.

Neal OReilly

16:53 09 Jan 26

Professional and very informative.

gloria paulson

19:42 08 Jan 26

Angie

17:42 08 Jan 26

Elaine Hills

14:51 07 Jan 26

Last Thursday Eric, the Interstate technician, was at my home for the annual furnace check-up. He discovered a failed inducer, which he explained would result in zero heat. He also found two zone dampers that were making noises indicating failure was coming soon. Eric explained how the dampers work and why they are needed as well for adequate, even heating throughout the home. He ordered the needed parts and less than a week later all parts are replaced and everything is in perfect working order for another Wisconsin winter season. The professionalism, knowledge and promptness with Interstate Heating is at the highest level. I have never been disappointed.

Linda Pitts

01:44 07 Jan 26

Dylan was prompt and very professional!!!! Great young man!!!!

Susan Haramaras

15:54 06 Jan 26

Josh arrived as scheduled. He explained everything. He was knowledgeable and efficient and completed the job to our satisfaction.

Chris or Beth Peske

14:59 06 Jan 26

Excellent service. Tristan was thorough, professional and informative.

Matthew Baker

00:48 03 Jan 26

Informative and professional. Did great work and cleaned things up.

1neilandkaren

21:00 02 Jan 26

⭐⭐⭐⭐⭐I called the morning after a holiday and Matthew was very helpful in getting us the support we needed. Chris arrived a little early and quickly diagnosed the issues with both our boiler and furnace. He was polite, knowledgeable, efficient, and cleaned up after finishing the work.We’ve worked with Interstate Heating multiple times, and they are always responsive and helpful—from the office staff to the technicians. They are honest and genuinely want what’s best for their customers. Highly recommend!

Karl Fritchen

17:51 02 Jan 26

Tristan did an awesome job! He communicated well about when he was going to arrive and then called me after the visit to outline what he had done and the costs related to it. Very positive experience and very professional technician.

Kathy Kowalski

00:01 01 Jan 26

Excellent prompt service.Technician found the issue quickly!

Harry Aghjian

17:26 31 Dec 25

Great service tech and solved the issue quickly… Tristen was awesome!

Julie Offutt

16:58 31 Dec 25

Tristan was amazing. He advised me to close vents/redirect air to the rooms that needed more heat and to leave on the fan to protect our HVAC system: : : he did suggest adding a line to the basement to give more heat as well which we will likely do.He was an extremely knowledgeable, skilled and kind service man : thank you-Julianne

Mike Greenwood

18:05 30 Dec 25

Chris Peterson

21:51 29 Dec 25

Melody Ruhbusch

17:13 26 Dec 25

Considering this was the day after Christmas we were grateful that Jason was available to assist us with our problem. He was very friendly and informative. Explained our options without any pressure.

Phil Prange

19:27 23 Dec 25

The technician arrived early. He was clean, courteous, and competent.My heating issue was resolved quickly and explained well.Can't say enough good things about Interstate and their service team.Chris was excellent.Thank you

Joanne Nolde

21:17 22 Dec 25

Antonio and his team installed a new furnace. They were knowledgeable, on task, and efficient in removing the old furnace, replacing the new one, and cleaning up before leaving. They were friendly, polite, and articulate in explaining what they were doing and answering my questions. I would definitely recommend them to others.

Karen Wright

20:20 18 Dec 25

I trust Interstate Heating. We have used them for27 years. Tristen was very thorough and figured out why were not getting heat in our bedroom.It all boiled down to a small part that had to be replaced. He was very diligent in finding the problem. He was great!!!! He also explained everything to me.A big thank you to Tristen

Bubba John

15:05 18 Dec 25

Eric installed a Aprilaire humidifier for us. He did a great job and we are very happy with it. The service was awesome and we highly recommend Interstate Heating.

Kathy miller

14:26 18 Dec 25

technicians showed up on time, laid down cloth on the traffic patten to the basement as it was a messy, sloppy day. stated it would be about a 4 hour install which was pretty accurate. afterwords they cleaned up everything and could not even tell they were here.

Tom Gannon

20:31 17 Dec 25

Eric does a great job. He is extremely knowledgeable and is an excellent communicator.

Harry Clayton

16:42 17 Dec 25

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

Kathy Greb

20:11 16 Dec 25

Chris completed annual maintenance on my furnace and humidifier. Very efficient, pleasant and answered all my questions.

Jack B

20:02 16 Dec 25

Chris did our furnace maintenance today. He answered all of my questions and provided good suggestions for moving forward.

david carlson

19:54 16 Dec 25

Tristan did a great job. He explained everything thoroughly. He was extremely polite.

Pedro Pierri

17:51 16 Dec 25

Furnace gave out after 15 years in one of the coldest days of the year. Interstate Heating was able to expedite the repair, get the part that was not readily available and complete the repair it on the same day. We have heat again! The technician that came in, Dylan, did an excellent job in repairing the problem and explaining what happened, how he was going to fix it and I even learned something new. I highly recommend their services.

Mary Lou Moths

01:02 16 Dec 25

ETHAN Lipski is a great employee. He is polite, respectful, and efficient. He takes time to answer my questions. 5 srars, for sure!

SANDRA ROBACK

21:14 15 Dec 25

Wonderful team- customer service (Mathew) and their service technician Eric were both outstanding to work with. Eric's knowledge and his ability to get our furnace working in matter of 1.5!!

LBRC Account

17:39 15 Dec 25

The service was quick and efficient. They always provide top tier service. They are my definition of being very professional. Highly recommended.

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

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.

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!

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

See all reviews Write a review

“We were told the blower replacement was going to be $2600 plus a $75 return trip fee. We checked with a few other HVAC companies and the price for a blower motor replacement was 2x what it should be. Call around for other service /replacement contractors before calling”

- Dan N.

“Tristan did a phenomenal job fixing my furnace and wall thermostat. He was very friendly and informative!”

- Nathan P.

“The team of Antonio Stanisch was very professional and courteous. They answered all my questions and walked me through the process. They also took all precautions to not damage any floors and left our place clean.”

- Johannes S.