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.

Learn More
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.

  • What does SEER, AFUE, and HSPF ratings mean to me?
    SEER, AFUE, and HSPF are all measures of energy efficiency. Air conditioners may look similar, but their Seasonal Energy Efficiency Rating (SEER) can vary widely. Higher SEER numbers save more money spent on electricity. A 13 SEER air conditioner, the EPA "current minimum standard", uses 23% less energy than a 10 SEER unit (EPA standard up until Jan. 2006). Even though 13 SEER is the minimum efficiency available, we currently offer a line of air conditioners that start at 13 SEER and go all the way up to 21 SEER. Higher SEER air conditioners can significantly reduce your electric bill depending on your average usage.

    Heat pumps have SEER ratings like air conditioners and Heating Seasonal Performance Factor (HSPF) ratings for measuring heating efficiency. Higher HSPF ratings mean greater energy savings. The HSPF scale range is 7.5 to 13.0.

    Today's new high-efficiency furnaces can save up to 50% in operating costs over a ten-year-old furnace. Many 1990 and earlier model furnaces have Annual Fuel Utilization Efficiency (AFUE) ratings of 65% or less. The minimum AFUE-rated furnace that can be sold in the United States as of May 1, 2013, is 80% in southern states and 90% in northern states.

    Our current product offering starts at this minimum AFUE rating and goes all the way to a very efficient 98.3% AFUE rating. Higher AFUE-rated furnaces can significantly reduce your gas bill depending on your average usage.
  • How can I reduce my energy costs?
    Cooling
    • Upgrade to a high-efficiency air conditioner - Swapping your old, inefficient air conditioning system for a high-efficient one can cut electricity bills by one-third. Consult one of our professional technicians to ensure your system is the right size for your home and you aren't over or under-cooling for your space needs.
    • Turn up the temperature - To save electricity during the summer, set the temperature above 75° as every degree below this will add an extra three to five percent to your energy bill.
    • Install ceiling fans - Change the direction of airflow on your ceiling fans. In the summer, the blades should operate in a counter-clockwise direction to create a nice, gentle wind.
    • Have annual maintenance performed - Having annual maintenance performed on your air conditioner by a licensed technician will help ensure it operates at its peak efficiency. It catches any potential breakdowns before they occur.
    • Don't block vents in well-used rooms - Keep your supply and return air vents free of objects like blinds, carpets, or furniture so your air conditioner can operate efficiently and there is even cool air distribution.

    Heating
    • Upgrade to a high-efficiency furnace - New high-efficiency furnaces use up to 50% less fuel than an older system. It can save you up to 25 percent of your home-heating costs in one year, and within a few years, you'll have recovered the initial cost of replacing/upgrading your furnace. Choosing a model with an energy-efficient motor can save 20 to 50 percent of the energy needed to operate a fan motor continuously. Let us show you the advantages of replacing your old furnace today.
    • Have annual maintenance performed - Having annual maintenance performed on your furnace by a licensed technician will help ensure it operates at its peak efficiency. It catches any potential breakdowns before they occur.
    • Install a programmable thermostat - A programmable thermostat lets you control your home's temperature when you're away or asleep. For every 1° you lower your thermostat for seven hours per day, you save one percent on your heating bill.
    • Don't block vents in well-used rooms - Keep your supply and return air vents free of objects like blinds, carpets, or furniture so your furnace can operate efficiently and there is even heat distribution.
    • Install ceiling fans - Change the direction of airflow on your ceiling fans. In the winter, the blades should operate in a clockwise direction, helping to push the warm air from the ceiling down into the room.
  • Is Freon as a refrigerant being discontinued?
    Yes. As of January 2010, the refrigerant R-22 (what consumers call Freon®) is no longer allowed to be used in manufacturing new equipment. R-22 has been used as the "standard" refrigerant for many years but has been found to be harmful to our planet by our government. All new air conditioners and heat pumps use R-410A, the more "environmentally sound" refrigerant.

    R-22 is still the most commonly used refrigerant in existing air conditioning equipment in residential homes today. However, per the Montreal Protocol, caps have been established to eliminate the production of R-22. In 2004, there was a 35% reduction; in 2010, there was a 65% reduction; in 2015, a 90% reduction; and finally, in 2020 a 99.5% reduction in the production of R-22. This means that during the time of these reductions with high demand, the price of each pound of R-22 refrigerant could potentially skyrocket.

    If you are considering replacing your existing air conditioning equipment, most higher efficiency products have already switched to R-410A, the more "environmentally sound" refrigerant.
  • Why should I switch to a high efficiency air filter?
    Proper air filtration is just as important to your heating and cooling system's health as it is to your family's health. Without proper filtration, dust and dirt can build up on your system, impacting operation and efficiency. A high-efficiency filter will remove more dust, dirt, pollen, mold, and other particles from the air. If you suffer from allergies or other respiratory problems, you should strongly consider a high-efficiency filter. No matter what type of filter you have, make sure you change it regularly.

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