Experience Custom Comfort Solutions Providing HVAC Services to the Tri-City Area Since 1984

HVAC Company in Bay City, MI

Trusted Local Heating & Cooling Solutions Since 1984

Need help with your heating or cooling system? At Custom Engineering, we’re a locally owned HVAC company based here in Bay City, proudly serving homes and businesses across Bay County, Saginaw County, and Midland County. We offer full-service heating and air conditioning installs, replacements, repairs, and maintenance, with a personal approach that puts your comfort first.

Whether you're dealing with an unexpected heating breakdown in the middle of winter, needing to stay cool during Michigan's humid summers, or planning an upgrade to a more energy-efficient system, our licensed and insured team is here to help.

We offer a full range of HVAC services:

  • Heating and furnace services: Installation, repair, and maintenance for gas, electric, heat pumps, and oil-based heating systems.
  • Cooling and AC services: Full AC replacements, seasonal inspections, and fast repairs to keep you cool through Michigan's hot summers.
  • Air quality and comfort: Thermostats, humidifiers, and air filtration systems to enhance indoor air quality and comfort throughout your property.
  • Emergency and same-day HVAC help: We’re available 24/7 to take your call and offer same-day service whenever possible, even if it’s just to talk through what can wait and what needs quick attention.

As authorized dealers for Trane and Mitsubishi Electric, we offer advanced, energy-efficient heating and cooling solutions, backed by factory warranties and our 5-year labor warranty on installations. 

Contact us today at (989) 474-2870 or online. for HVAC services in Bay City or surrounding areas. We’re available 24/7 to take your call.

Financing Available Invest in your home comfort today with our financing options!
Proudly Serving the Tri-City Area

Custom Engineering is proud to serve Bay City, Linwood, and other surrounding areas.

  • Auburn
  • Bay City
  • Beaverton
  • Bentley
  • Birch Run
  • Bridgeport
  • Burt
  • Chesaning
  • Coleman
  • Essexville
  • Frankenmuth
  • Freeland
  • Hamilton
  • Hemlock
  • Horton
  • Kawkawlin
  • Merrill
  • Midland
  • Oakley
  • Pinconning
  • Saginaw
  • Sanford
  • Shields
  • St. Charles
  • Zilwaukee

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How Can We Help You?

Service That's Fast, Reliable, Always Available

When you trust Custom Engineering, you can know the job will be done right the first time.

Designed for life, inside and out.

Mitsubishi Electric is a leading provider of HVAC systems in the United States. Learn how we can help you.

Why Bay City Locals Choose Custom Engineering

We’re more than just a service company; we’re your neighbors. Our team takes the time to talk through your options, explain the work, and treat your home with care. You can reach us anytime — we’ll walk you through the next steps and help you decide if service is needed now or can wait.

We also offer:

  • Free estimates on all installs and replacements
  • Financing options through Wells Fargo and Michigan Saves
  • Reliable, friendly service from a team that knows Mid-Michigan homes and weather

Serving the Tri-Cities Area

  • Bay City
  • Saginaw
  • Midland
  • Bay County 
  • Saginaw County
  • Midland County

Whether you're in downtown Bay City, a neighborhood in Midland, or just outside Saginaw, we’re familiar with the properties, the weather patterns, and the HVAC needs across our region.

Continue Reading Read Less
    "They really came through!"
    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.
    "Custom Engineering took care of us right away!"
    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.
    "I don't know what I do without this company!"
    Chaz did an amazing job - straightforward and very helpful. Jason and Trey set up the furnace a week ago, and it runs amazingly! It's nice to stay warm again. They just repaired and replaced my bathroom exhaust fan, too. Thank you again!
    - Cesily W.
    "Nick was fantastic!"
    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.
    "They did a great job!"
    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.
    "This business is the best!"
    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.
    "They have been an excellent company to work with."
    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.
    "They did an excellent job - all in one day!"
    I always try to keep my business local, so I called Custom Engineering. They always answered my calls promptly, and the service was friendly with experienced technicians. They were prompt, courteous, and really put my fears to rest. Great job!
    - Debbie M.
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Mitsubishi Electric Comfort Solutions for Michigan Homes & Businesses

As a Mitsubishi Electric Ductless Pro Elite Contractor, we're trained directly by the manufacturer to install and service their systems with precision. These setups are a smart choice for homes and small businesses throughout Bay City, Saginaw, Midland, and the surrounding Mid-Michigan area.

Whether you need targeted comfort for a single room or a whole-property solution, Mitsubishi Electric systems deliver efficient heating and cooling without the hassle of traditional ductwork. They’re quiet, adaptable, and especially useful in older properties, home additions, or areas with inconsistent temperatures.

These systems are a smart way to reduce energy costs and improve comfort, especially where standard systems fail. As Ductless Pro Elite Contractors, we also offer extended warranties and access to exclusive models you won’t find anywhere else.

Contact us today at (989) 474-2870 or online for HVAC help in Bay City and beyond.

  • Affordable Financing Options
    We make HVAC services affordable with financing options offering 0% interest for 72 months.
  • Available Nights & Weekends
    No matter when you need us, we're ready to help. Someone is always available to answer your call.
  • Preventative Maintenance Plans
    Keep your system in perfect shape all year round with our programs.
  • Locally Owned & Operated
    As a proud Michigan company, we deliver honest, dependable HVAC services backed by local expertise and care.