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HEATING and COOLING

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.

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RADIANT HEATING

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!

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INDOOR AIR QUALITY

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.

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SHEET METAL ROOFING

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.

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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.

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Proudly Partnered with

Brewers
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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.

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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 Repair in Sussex, 53089

“Came to my help quickly, Josh the technician gave my furnace a thorough check, and an honest opinion. Very satisfied with their work. Thanks!”
- Robert H.

Gas Furnace Repair in Milwaukee, 53228

“Eric came early (yay!) and quickly determined the problem was that my new air filter that was too restrictive, causing a short cycle and the associated heating problems that go along with it. He replaced the filter and the problem was resolved. They should all be this easy!”
- Tom M.
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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.

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HVAC technician performing maintenance on a heat pump.

4 Important Heat Pump Tips

March 15, 2025
You could save up to 30 percent on your energy bill when you perform maintenance that support ideal system efficiency, according to the IAQA. Read More
HVAC technician performing maintenance on a furnace.

Why Is My Furnace Leaking Water?

February 28, 2025
Just so you are aware, the worst-case scenario is a faulty furnace secondary heat exchanger, but it is only for high-efficiency furnaces. Read More
The Basics of Winter Indoor Air Quality

The Basics of Winter Indoor Air Quality

February 15, 2025
In the winter, being snug as a bug in a rug in your home can be cozy, but it can also play havoc with your indoor air quality (IAQ) here in Wisconsin, creating some significant health problems. At Interstate Heating Co Inc, we recommend taking precautions to avoid the common issues associated with winter indoor air quality. Read More
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