Fast, Reliable Service 24 Hours a Day


Fast, Reliable Service 24 Hours a Day


System Special

Furnace and
Air Conditioner Installed for $5,295

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Team Members with 15+ Years Experience




We Earn Our Reputation for Heating and Cooling Excellence on Every Job

 There’s a reason Interstate Heating is the HVAC company home builders and homeowners trust for comfort without compromise. For over 50 years, we’ve offered straight-forward service and a full range of heating, cooling, and indoor air quality options by expert technicians. We know exactly how to make you comfortable, and go above and beyond what many others are capable of. From designing custom ductwork and complex systems to installing radiant systems and smart controls, we can work with any space, need, or budget.

New Construction HVAC Installations Are Our Specialty

With over 20,000 new boiler, furnace, air conditioner, and air quality system installations to our name, trust that we are prepared for any challenge. And as one of the largest Carrier® dealers in Wisconsin, we provide excellent pricing, a strong warranty, fast delivery, and factory-trained technicians and installers to help you every step of the way—from choosing the best system for your home to providing maintenance services that help it run reliably for years to come.

Heating Services

We Design, Install, Maintain, and Repair Heating Systems for Every Home
From high-efficiency furnaces and custom ductwork to boilers and in-floor radiant heating, Interstate makes it easier to heat your home or business your way. We also offer ductless systems that can replace space heaters in hard-to-heat rooms, zoning that directs warmth where you need it most, and even garage heaters that make transitional areas or storage spaces more comfortable all year long.

Cooling Services

Interstate Installs Air Conditioning and Services All Cooling Systems
We specialize in central air conditioning, ductless split systems, and zoning to customize cool comfort for residential and commercial clients. We address other hot topics with dehumidifiers to make the air less muggy, dual-purpose heat pumps that heat and cool your home, and programmable or Wi-Fi thermostats so you can adjust settings whenever the weather or your plans change. in.

Indoor Air Quality Services

Fresh, Clean Air Matters More Than You Think
When air is trapped inside, it quickly collects harmful gases and particles, dust, viruses, and odors—all of which can aggravate respiratory problems, cause headaches, and make your really uncomfortable. Minimizing allergens and pollution while managing humidity levels are keys to more complete indoor comfort—we deliver results with our purifiers, humidifiers, ultraviolet lights, and more.

Heating and Cooling Comfort for Nine Counties, Whenever You Need It

Our service area is as broad as our range of HVAC services. We welcome new home construction and commercial installation projects in nine counties throughout southeastern Wisconsin, and offer maintenance and repairs as needed, by appointment or on an emergency basis. From Germantown and Menomonee Falls to Delafield and Dousman, we bring comfort home to hundreds of families every month.


24 Hour Emergency Service

If you need immediate service after hours, dial 262-246-4772 and listen for the emergency on-call number.


Find out about current coupons, energy rebates, and cash incentives.

Ask the Experts.

There’s a reason Interstate Heating is the HVAC company home builders and homeowners trust for comfort without compromise. For over 50 years, we’ve had answers to all your heating, cooling, and indoor air quality questions—click below to read our responses to the ones we’re asked most often. If you don’t find your answer here, just call us—we’re also known for providing straight-forward advice to help you feel comfortable—in your home and with us.

N53 W24950 S. Corporate Circle
Sussex, WI 53089

Phone: 262.246.4772
Fax: 262.246.0296