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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.
  • Convenient Financing Options

    We make HVAC services manageable with convenient financing options.  Subject to credit approval.

  • 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 financing through Wells Fargo for those who qualify with approved credit. 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 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.

  • Akron
  • Au Gres
  • Auburn
  • Bay City
  • Beaverton
  • Bentley
  • Birch Run
  • Bridgeport
  • Burt
  • Chesaning
  • Coleman
  • East Tawas
  • Essexville
  • Fairgrove
  • Frankenmuth
  • Freeland
  • Greenbush
  • Hamilton
  • Hemlock
  • Horton
  • Kawkawlin
  • Lupton
  • Merrill
  • Midland
  • Montrose
  • Oakley
  • Omer
  • Pinconning
  • Reese
  • Rose City
  • Saginaw
  • Sand Lake
  • Sanford
  • Shields
  • Skidway Lake
  • St. Charles
  • St. Helen
  • Standish
  • Sterling
  • Turner
  • Twining
  • Unionville
  • Whittemore
  • Zilwaukee

Serving Bay City, Saginaw, Midland & Beyond

We provide services, 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 and receive support from one of our team members.

Financing Available Invest in your home comfort today with our financing options! Subject to credit approval.

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.

  • I am concerned about mold growth, what should I do?
    Molds are part of the natural environment. Outdoors and molds play a part in nature by breaking down dead organic matter, such as fallen leaves and dead trees, but mold growth should be avoided indoors. Molds reproduce by means of tiny spores; the spores are invisible to the naked eye and float through outdoor and indoor air. Mold may begin growing indoors when mold spores land on wet surfaces. There are many mold types, and none will grow without water or moisture. Click here to learn more about mold prevention in your home from the EPA.

    When humid air passes over chilled cooling coils, water condenses and drips through the coils into a collection pan, from which it continuously drains. Problems with these systems may occur when this water collects and becomes stagnant when it becomes blocked, either on the coils or in the drip pan. The pan will quickly grow mold that can infect your home with dangerous mold spores. Problems also exist when the HVAC ducting contains microscopic mold spores that stay continually present and blow contaminants around the home or office, often caused by mold in other parts of your home.

    You can do 3 things to prevent mold growth in your system:
    1. Preventative maintenance will ensure that the collection pan under the indoor coil stays clean and clog-free.
    2. Install ultraviolet lights next to the cooling coils to kill any mold or bacteria growing on the coils or collection pan.
    3. Keep your ductwork clean, and use a high-efficiency filtration system to keep your entire HVAC system clean.
  • How can I reduce allergens and improve the air quality in my home?
    With a high-efficiency air cleaner, you can remove up to 99% of the pollen and spores that find their way into the home. There is also a great reduction in household dust, dirt, smoke, and other air pollutants. Your indoor air will become cleaner and fresher while reducing the allergens and dust circulating throughout the house. With a whole-house humidifier, you can relieve the irritating discomfort of dry indoor air. The humidifier reduces itchy skin, scratchy throats, static electricity, and damage to your furnishings and woodwork. Since humid air feels warmer than dry air, you do not have to set the thermostat as high to feel the comfort you want. A lower thermostat setting will reduce the costs of your energy bill.
  • My air conditioner is very loud when I entertain outside, what can I do?
    A difference of 6 decibels (such as between 72 dB and 78 dB) is technically a four-fold increase in compressor sound when rating air conditioners or heat pump units. However, it takes a difference of 10 decibels to double the loudness. It is also noted that it takes approximately 3 decibels for the average human ear to discern any loudness difference.

    Great strides have been made in reducing the operating sound level of equipment. We will be happy to show you the difference in sound ratings with our product line.
  • 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.

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