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When it comes to your comfort, our Interstate Heating Co. professionals are experts. Our team is trained, certified, and ready to take care of whatever your HVAC needs may be.


The installation of radiant floor heat costs more initially than more conventional heating systems, but in the long run, it saves money due to lower thermostat settings and higher efficiency. Call Interstate Heating Co. to schedule a quote today!


Your indoor air quality (IAQ) is central to your health and comfort. Enjoy a breath of fresh air and allow our team to find solutions that improve the air quality at your home or business. Let us help keep you safe and comfortable.


Call Interstate Heating Co. to speak with one of our certified technicians about how a sheet metal fabricated roof can be a durable, cost-effective, and on-demand solution for you.

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 a Carrier Factory

Authorized Dealer

Carrier Factory Authorized Dealers work hard for this designation. And all their experience and work is for one purpose—to create comfortable homes and satisfied customers. So when you need a new system, or it’s time to service or repair your current equipment, you can trust you’re working with the best in the business.


We love hearing from our customers! If you’ve had us work on your HVAC system we would love to hear from you too.

Gas Furnace Installation in Waukesha, 53186

“Jason did a great job installing our new furnace.”
- Jim H.

Indoor Air Quality Installation in Sussex, 53029

“The installation went perfect. The Aprilaire is great and the service from your company was second to none.”
- Robert M.

Gas Furnace Installation in Milwaukee, 53221

“Jason Berg installed my new furnace. He was a very pleasant person and great at his job. The install went very well and the instruction on setting up the new thermostat was extremely helpful. Everything went smoothly and the care and clean up afterward were amazing! It was a very nice experience and I would highly recommend your company to anyone needing a furnace.”
- Nancy M.

Three Generations Strong

After all this time, we still follow the most basic rule of business: we treat our customers the way we want to be treated. And we know that comfort is a big part of what makes a house a home, so we make it easier to create and care for an ideal environment.

Image of a person. Video - Why Does My Furnace Smell Like Gas When I Turn it ON?

Video – Why Does My Furnace Smell Like Gas When I Turn it ON?

December 29, 2022
You turn on your furnace, and you smell gas. What should you do? Read More
Image of someone pressing control panel attached to hvac system. Heat Pump Versus Furnace.

Heat Pump Versus Furnace

December 23, 2022
Looking to install a new heater in your Sussex home? Your two most popular choices are a heat pump and a furnace. Each one has advantages and disadvantages when compared to the other. Read More
Image of someone looking concerned while laying down. Video - Why Is My HVAC Unit Making Unusual Noises?

Video – Why Is My HVAC Unit Making Unusual Noises?

November 29, 2022
If you hear any unusual noise coming from your HVAC unit, please turn it off and call us. Don’t attempt any kind of repair without consulting an HVAC certified technician first. Read More