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Need to Improve your Indoor Air Quality This Fall?

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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.

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!

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.

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.

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.

“Workers were competent and professional. They did, however, leave something undone near the air conditioner. They did return promptly and resolve the issue.”
- michael J.
“Interstate Heating was a lifesaver this morning (10/16/24). They were very responsive to my needs (that started the late day before). My situation was this, I had a local company into my home for a furnace cleaning and tune-up (because I had a discount coupon for the work). They arrived at 2:00 pm. After 2.5 hours they completed their work (I’m assuming it took that long because the lead technician had a “trainee” with them. The reason I am assuming that is that every time I went to observe the lead technician was providing direction to the trainee). At the end of the work, I was informed that my Carrier variable speed inducer assembly had failed during a performance test ( I had no idea what that statement exactly meant). Once I had been given that information I was also informed that to improve the performance of my equipment I may need to replace the system’s motherboard as well as move the intake piping from above the gas valve (I didn’t tell the technician one of their associate technician’s had also made that comment two years earlier….no change in condition). All combined the quote was close to $1,500. But that wasn’t the most significant fact. When the technician told me there was equipment failure they didn’t indicate positively that the furnace won’t work due to that component failure. This was at 4:30 pm….which meant it was too late to make a decision about what I was going to do….which meant no heat for the evening. An acceptable ending to this part of the story is my wife and I survived a below-freezing evening in our house! In the morning, I called Interstate at 8:00 am (I put my information into them both on their website and through their chatbot the evening before). When Ellen answered the phone she had already viewed my input from the previous night. She was very conversant with my situation. We had a longer conversation about my needs and she then directed me toward their appointment scheduler. Within approximately 30 minutes Jessica called to tell me there was a technician in my area that would be available late morning. Casey arrived at approximately 10:30 am. He would have been at my home earlier but he had to go pick up the parts from the Interstate location. He was able to pretty quickly assess and repair the equipment. The inducer assembly was the only component replaced. Both the motherboard and piping were deemed a “non-issue” so were not included in the repair. The original quote for just the inducer assembly replacement was approx. $500. My payment to Interstate (with the trip charge….which did not include the “go get” parts run that Casey had to do before arriving) was less than $215 (which was over a $250 savings…..). Casey was highly professional, very timely, very courteous, and a pleasure to work with. I will continue to be a loyal customer of Interstate (they installed the furnace in 2015 and our AC equipment in 2023) going forward. And will try to restrain wanderings to other company’s because of their “good deals”. I have learned my lesson.”
- Mark K.
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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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Transitioning Your Heat Pump. Close-up of black full inverter heat pump outside in the garden, near wooden pool house on a sunny day. Lens flare on the image.

Transitioning Your Heat Pump

October 15, 2024
One reason Wisconsin homeowners love heat pumps is they function as an all-in-one unit. Instead of purchasing and maintaining a separate furnace and air conditioning system, you can simply transition your heat pump from the heat setting to the cooling setting and vice versa as seasons warrant. Read More
What’s That Smell Coming From My Furnace? Worried senior smartphone user getting bad, concerning news message, holding mobile phone, looking away, feeling stressed, anxious, thinking over problems, sms answer.

What’s That Smell Coming From My Furnace?

September 30, 2024
If your furnace is producing a strange smell, you should always treat it with caution. While the cause for the odor may be benign, it could just as easily be harmful to inhale. When in doubt, always open windows to ensure ventilation, and evacuate your Mequon home. Read More
Fall HVAC Maintenance. Father In Autumn Garden Gives Children Ride In Wheelbarrow.

Fall HVAC Maintenance

September 15, 2024
Here in Wisconsin, we’ve reached the season that makes you say, “Gosh, it’s so dark out. Is it really only six in the evening?” Before the days get too short, remember to check off heating, ventilation, and air conditioning (HVAC) maintenance from your autumn to-do list. Read More