About Us Custom Engineering

About Us 

Local Heating & Cooling Solutions for Homes & Businesses in the Great Lakes Bay Region

Since 1984, we’ve served homeowners and small businesses across Bay City and surrounding areas with heating and air conditioning solutions built to last. At Custom Engineering, we’re a locally owned and operated HVAC company based here in Mid-Michigan, and that local focus shapes how we do business every day.

Whether we're on a call in Saginaw, handling an installation in Midland, or walking someone through a late-night issue over the phone, our goal is always the same: to work with people in a straightforward, honest, and helpful way.

See How We’re Giving Back We're proud to support our Bay City community through local events, partnerships, and service.
  • 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.

Hear From Our Happy Customers

    "So grateful to them!"
    I needed help, and Custom Engineering got to me fast and saved the day. Nick, the technician, was great. He was personable and intelligent and he got my repair done super fast. Thanks, Custom Engineering!
    - James T.
    "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.
    "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.
    "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.
    "10/10 Service!"
    Had Customer Engineering come out to my restaurant to diagnose my furnace and walk-in freezer. Brandon and Skylar, the techs, were amazing. Extremely friendly and knowledgeable. I will be using them for all my HVAC needs moving forward.
    - Taylor A.
    "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.
    "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.
    "My experience with the company was great!"
    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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Who We Are

We’re a team of long-time HVAC professionals with deep roots in the Bay City area. Over the years, we’ve grown from a small outfit into a trusted resource for homes and businesses across Bay, Midland, and Saginaw counties. Even as the industry has changed, we’ve stayed focused on what matters most: showing up, listening, and offering the kind of personal service that keeps people comfortable through every season.

We’re licensed and insured and offer full-service heating and cooling, from repairs and tune-ups to complete system replacements. Whether you’re dealing with a furnace issue in February or trying to cool down your home in July, we’ll help you explore options that fit your space and budget.

Our Approach

We don’t believe in high-pressure sales tactics or one-size-fits-all answers. Every call we get is a little different, and that’s precisely how we treat it. If you're unsure whether something’s urgent, we’ll talk it through and help you figure it out, no obligation, no runaround. Sometimes we can walk you through a quick fix over the phone. If not, we’ll let you know what the next steps might look like.

We also offer free estimates on new system installations and 0% financing through Wells Fargo for those who qualify. Whether you're replacing older equipment or planning a more efficient setup, we’re happy to explain your options and answer any questions.

Proud to Offer Mitsubishi Electric Systems

We’re trained and equipped to install and service Mitsubishi Electric systems, one of the leading names in ductless and energy-efficient heating and cooling. These systems are a smart choice for Michigan homes and businesses, especially when dealing with hard-to-condition spaces or older ductwork. Being a Mitsubishi Electric Ductless Pro Elite Contractor gives us access to extended warranties and product options beyond standard dealer offerings.

Need HVAC help in Bay City or nearby? Call (989) 474-2870 for 24/7 support.

BE COMFORTABLE IN EVERY SEASON Check Out Our Preventative Maintenance Programs

With regular tune-ups, special discounts, and priority service, our programs will keep your equipment in quality shape year-round.

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

Serving Bay City, Saginaw, Midland & Beyond

We provide same-day service, emergency repairs, and full HVAC replacements for homes and small businesses across Bay City, Saginaw, Midland, and surrounding areas, including Auburn, Bay County, Saginaw County, and Midland County. Whether it's a quick repair or a complete system upgrade, we deliver reliable support at competitive prices.

Contact us today at (989) 474-2870 for 24/7 support from one of our team.

Financing Available Invest in your home comfort today with our financing options!

Ask the Experts

Common Answers To Your Questions

Curious about heating and cooling? Our Custom Engineering team has you covered. Browse through common questions and find expert advice straight from our pros.

  • Can I just replace the outdoor unit on an older system to save money?
    No. Replacing only the outdoor unit will lower the efficiency of the unit. In fact, you can lose up to 15% of the unit's efficiency! Even worse, your system may fail sooner than normal and most manufacturers' warranties will be voided. You should always replace the indoor cooling coil with the outdoor unit.
  • What is a Geothermal system?
    The Earth absorbs almost 50% of all solar energy and remains at a constant temperature of 50°F to 70°F, depending on geographical location. A geothermal unit utilizes this constant temperature for heating and cooling your home. You can save up to 60% on your power bills compared to a traditional system. There is no flame, flue, odors, or loud outdoor equipment. Heating, air conditioning, and hot water can all be attained from a single compact unit.
  • Why should I buy Energy Star labeled equipment?
    The average home spends about $1,900 annually on energy bills. Heating and cooling accounts for as much as half of a home's energy use. The EPA provides important recommendations for energy-efficient equipment, including proper sizing, quality installation and maintenance, and other home improvement considerations to help you get the most out of the heating and cooling products you purchase, save energy, and save as much as 20% annually on your total energy costs.

    ENERGY STAR-qualified products prevent greenhouse gas emissions by meeting strict energy efficiency guidelines set by the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Energy (DOE).
  • How does 2-Stage heating or cooling work?
    2-stage cooling is a method that can better manage your home's cooling while outdoor temperatures are changing. It can also better maximize indoor comfort and energy efficiency. 2-stage cooling systems are typically the most energy-efficient systems out there.

    2-stage cooling can be done by having one unit with two compressors, one small and one large. The small one is typically capable of putting out about 50% of the capacity of the larger one. The second way to have 2-stage cooling is to have a single scroll unloading compressor. This compressor can unload its capacity down to about 66% of maximum capacity. Both these methods of getting 2-stage cooling allow the unit to run at a lower stage when the high stage is not needed. By doing this, energy is saved.

    2-stage heating has the same principle as 2-stage cooling. It allows the unit to adjust itself based on the amount of heating that is necessary. 2-stage heating is a good way to save on heating costs.

    A heat pump system would have two different-sized compressors, a small and a large one. The compressor that is used at a given time would depend upon the need. If only a small amount of heating is necessary, the smaller compressor would be used to save energy. The large compressor would only be used when a large amount of heating was needed.

    A 2-stage gas furnace has a modulating gas valve that regulates gas flow depending upon the need.

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