
Bay City Furnace Services
Furnace Repairs, Replacements & Installations Throughout the Great Lakes Bay Region
When the cold Michigan air settles in, you need a furnace that’s ready to keep up. At Custom Engineering, we’ve been helping homeowners and small businesses stay warm through Bay City winters and those sharp winds off the Saginaw River since 1984.
If your furnace blows cold air, cycles on and off, or just not heating like it used to, we can take a look and figure out what’s going on. We handle repairs, replacements, and new installations, and we’re always glad to walk you through your options in a way that’s easy to understand.
Thinking about upgrading to a high-efficiency furnace? We’ll help you choose a system that fits your home’s layout, comfort needs, and budget. We work with trusted brands and provide free estimates for installations and replacements.
As a Bay City-based team, we know what Michigan winters can throw at you—and we’re ready to help when you need it. Someone from our team will answer your call 24/7, and we offer same-day service when available.
Need furnace help? Contact us anytime at (989) 474-2870 or online to schedule a service.

Custom Comfort, Professional Care
What Makes Us Different?
At Custom Engineering, we will always put you first. That's why so many people in Linwood trust us time and again.
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Affordable Financing OptionsWe make HVAC services affordable with financing options offering 0% interest for 72 months.
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Available Nights & WeekendsNo matter when you need us, we're ready to help. Someone is always available to answer your call.
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Preventative Maintenance PlansKeep your system in perfect shape all year round with our programs.
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Locally Owned & OperatedAs a proud Michigan company, we deliver honest, dependable HVAC services backed by local expertise and care.
Our Furnace Repair Service
We know how quickly the cold can set in here in Michigan, and how frustrating it is when your furnace isn’t working properly. Whether you're dealing with uneven heating, strange sounds, or a system that’s just not running as efficiently as it should, we're here to help troubleshoot and get things back on track. No matter where you are, whether in the city or out in a more rural area, we’re ready to assist with same-day and emergency service when available.
Furnace Installations & Replacements
When repairs no longer make sense, or you’re ready for a more efficient system, we’re here to help you through the upgrade. We install a range of furnace types, including Trane gas models, oil systems, and Mitsubishi Electric ductless units that are great for properties without central ductwork.


Trusted by homeowners and Businesses Since 1984
At Custom Engineering, your satisfaction is our priority! See for yourself what our customers have to say about working with us.
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Always courteous & competent. They installed a new furnace, AC, garage gas heater, and ran a gas line into our laundry room. They stayed on the job until all was completed and we were extremely satisfied.- Terrance V.
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We bought our kitchen hood system from them, which they also installed (no small task). They are dependable, efficient, and do great work. Prices are what I would expect for the job. Don't hesitate to hire them.- Marinell S.
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He got our furnace up and running again very quickly (on a Saturday!). Very personable and professional! We will definitely be using Custom Engineering Heating & Cooling again - thank you!- Krista W.
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Our initial call was after hours and not an emergency. We received a call first thing the next morning, and they came out within a few hours. Both gentlemen were very professional and knowledgeable, and were able to repair our furnace right then and there.- Reid K.
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We went through custom engineering for replacing our furnace and air conditioner. They went above and beyond to do what is best for our home. The whole team was respectful and informative. They answered any questions we had!- Allison E.
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Every employee I have had the pleasure of dealing with has been top-notch. Today's visit by Tyler for annual maintenance was great. He was punctual, friendly, and professional.- Michelle G.
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Chaz went above and beyond! He fixed my main house furnace and also advised me on my ceiling-mounted furnace in my back building. Thank you for your quick response. I will use you again!- Ann K.
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Quick, efficient, and friendly service from both office staff and techs. Fair pricing. Grateful for their help on a freezing day when our furnace failed. Feared the worst. Highly recommend this company!- Tammie S.
Seasonal Furnace Maintenance
Regular furnace maintenance helps your system run more efficiently and can prevent unexpected issues during the coldest months here in Bay City and the Great Lakes Bay Region. With the temperatures dropping and lake winds picking up, having a furnace that’s ready for the season makes a big difference in your home’s comfort.
During a seasonal tune-up, we handle the important tasks that keep your furnace in top shape. We’ll clean the burners, inspect the blower components, check safety controls, and examine the electrical connections. For oil furnaces, we also clear out built-up soot and check the nozzle and filter, helping the system burn fuel more cleanly and efficiently.
Whether you're after a quick once-a-year check or prefer a more regular service plan, we offer flexible options that work around your schedule. If something doesn’t seem right during the tune-up, we’ll take the time to walk you through what we find and discuss the best next steps based on your furnace’s setup.