
At The Thielmann Group, our team has been offering reliable heating, air conditioning, and HVAC repair services in Oak Creek, Wisconsin and other areas for over 90 years. Our comprehensive residential and commercial HVAC service ensures that your Oak Creek property is always at the ideal temperature.
Our NATE-certified technicians have the skills and experience to handle any heating or cooling issue and provide service for all brands of equipment, and with our 24/7 emergency services, we are here for you when you need us most.
For superior HVAC service in Oak Creek, trust the team at The Thielmann Group by calling (262) 315-3067 today or contact us online!
Top-Rated AC Services
Our licensed and insured technicians are proud to provide you with outstanding air conditioning (AC) services in Oak Creek, Wisconsin. With our wide range of services, we will work to ensure that you have the cooling power, including:
- AC installation and replacement
- AC repair
- AC maintenance
Ductless Mini-Splits
In addition to forced air, our team provides service for ductless mini-splits. With these unique systems, you’ll get great benefits, including increased energy efficiency, decreased noise, and easy maintenance, all without relying on ductwork in your home.
Heat Pumps
To streamline your HVAC, consider a heat pump. These systems work to both heat and cool your home and can provide exceptional performance with maximum energy efficiency.
Reliable Heating Services
Our comprehensive HVAC and heating services include installation, replacement, repair, and maintenance of a wide variety of popular heating systems, including:
- Gas and oil furnaces: Furnaces are always a popular choice for heating and offer great energy efficiency.
- Boilers: Boilers require less fuel for heating and are cost-efficient while providing quiet and consistent heat.
- Heat pumps: A heat pump does double duty to heat and cool your home and is a highly energy-efficient option.
When you need unmatched heating service, trust the team at The Thielmann Group. Call us today at (262) 315-3067 to schedule services!
Ductwork Services in Oak Creek
Your ducts are responsible for moving heated and cool air throughout your home and are critical to your home’s comfort system.
We offer a variety of duct services to ensure that your home is at the perfect temperature, including:
- Duct cleaning
- Duct installation & replacement
- Duct repairs
- Duct maintenance
Schedule your ductwork service today by calling (262) 315-3067 or contacting us online!

Indoor Air Quality Services
At The Thielmann Group, we understand the importance of high-quality indoor air. With our indoor air quality services, we’ll help ensure that the air you and your family breathe daily is clean and safe.
We offer a variety of systems, including:
- Air purifiers: These systems clean your air using a high-efficiency filter on the air your HVAC system is pushing into your ducts.
- Whole-house humidifiers & dehumidifiers: Moisture balance is critical for fresh air in your home, and with a whole-home humidifier or dehumidifier, you can prevent issues like mold, mildew, dry skin, and snoring.
Don’t delay! Get clean air today by calling (262) 315-3067 or contacting us online today!
Packaged Units Services
Packaged units are all-in-one systems that provide heating and cooling from a single unit. With these systems, you’ll get maximum efficiency with a simple installation and quiet performance. These units are often an ideal choice for smaller homes.
Our services include:
- Packaged unit installation & replacement
- Packaged unit repairs
- Packaged unit maintenance
Interested in a packaged system? Call our team at (262) 315-3067 or contact us online to see if this option is right for you!

Reliable Plumbing Services in Oak Creek, WI
If left unattended, a plumbing problem can quickly go from a minor inconvenience to a major repair. When this happens to you, call Thielmann Heating, Cooling, and Plumbing! Our team of plumbers in Oak Creek have the training, experience, and tools needed to locate and repair any problem with your plumbing system.
We fix everyday problems like dripping faucets, slow drains, and leaking pipes. We also handle larger projects, including full pipe replacements, water heater upgrades, and sump pump installation. Our goal is simple; keep your plumbing system reliable and your home safe from water damage.
The Oak Creek plumbers from Thielmann offer:
- Leak detection and pipe repairs to stop hidden issues before they spread.
- Drain cleaning to clear blockages and keep water flowing fast.
- Garbage disposal repairs or installations to make kitchen cleanup simple.
- Water heater service, repair, or replacement to keep your hot water consistent.
- Fixture installation and repair for toilets, sinks, and faucets that need attention.
- Water filtration and softening solutions for cleaner, better-tasting water.
- Sump pump repairs and maintenance to protect your basement from flooding.
We believe every repair should last. Our licensed plumbers find the root cause, fix it correctly, and make sure you understand the work before we leave. We also perform routine plumbing checks to catch small problems before they become major repairs. For clear pricing, honest recommendations, and lasting results, call Thielmann Heating, Cooling, and Plumbing today at (262) 315-3067 to schedule your Oak Creek plumbing service.
Choose The Thielmann Group in Oak Creek
For unmatched customer service, trust the team at The Thielmann Group. We’re proud to offer residents of Oak Creek superior service from our background-checked, licensed, and insured technicians, and with our upfront pricing, you’ll never get a surprise when it’s time for the bill.
We offer free estimates on replacements and service all brands, and with our available financing options, you can trust that you’re in excellent hands with The Thielmann Group.
Schedule your HVAC service with one of our experts today by calling (262) 315-3067 or contacting us online today!
Read Reviews by Our Customers
EXCELLENT Based on 542 reviews Posted on Stephanie DolnikOctober 10, 2024Trustindex verifies that the original source of the review is Google. Everyone that I have ever came into contact with there has been helpful and wonderful! I would recommend them to anyone!Posted on Aaron WilhelmJuly 19, 2024Trustindex verifies that the original source of the review is Google. Gave me a quote to replace my 29 year old air conditioner.They weren’t the cheapest but were priced with in reason. Installed it quickly and operates wonderfully. I couldn’t be happier.Posted on Lisa FarrellJuly 19, 2024Trustindex verifies that the original source of the review is Google. My husband and I received 5 quotes from 5 different companies before finally deciding upon Thielmann. Although Thielmann was a bit more expensive, the quality we received was outstanding. We went through the Costco Program (Lesa at Menomonee Falls) and received more rebates in doing so. With that program, we received 10% back on our Lennox Air Conditioner and Lennox Furnace. In addition, we received another 2% back by going through Costco and another 2% back by putting it on the Costco Visa card. At any rate, from, Jason, who came to our house to explain what would be done and provide the estimate, to the installers, Ben and Hayden, who provided excellent care installing our new products. They spent the entire day replacing our new HVAC system. The guys were extremely professional and had great precision. Thank you, Thielmann, for a wonderful HVAC system, great customer service, and an amazing job!Posted on Dave SeefeldtJuly 19, 2024Trustindex verifies that the original source of the review is Google. Professional and fast! Installation looks great!Posted on De'Angelo TatumJuly 15, 2024Trustindex verifies that the original source of the review is Google. I liked my experience with them. The guys I spoke with prior to doing the work, the estimation phase , and the ones I spoke with after the work was completed had enough knowledge and suggestion to answer all my questions. I’m pleased with the job they did. I had two AC units installed.Posted on Jay OrcholskiJuly 14, 2024Trustindex verifies that the original source of the review is Google. Wayne helped us find the right equipment. Ben and Hyden were great with the install. Wonderful team, as I would highly recommend The Thielmann Group.Posted on Brad DeFauwJune 26, 2024Trustindex verifies that the original source of the review is Google. I recently had the pleasure of working with The Thielmann Group Heating & Air Conditioning to install a mini-split HVAC system for the second floor of our Cape Cod home in Cedarburg, WI, and I couldn't be more satisfied with the entire experience. Professionalism and Expertise: From the initial consultation to the final installation, the team at The Thielmann Group demonstrated exceptional professionalism and expertise. They took the time to thoroughly assess our home and understand our specific cooling needs. Their knowledgeable staff answered all our questions and provided valuable insights into the benefits of a mini-split system for our unique architectural setup. Quality Installation: The installation process was seamless and efficient. The technicians arrived on time, were courteous, and worked diligently to complete the installation with minimal disruption to our daily routine. They were meticulous in their work, ensuring that everything was installed correctly and neatly. I was particularly impressed with their attention to detail and their commitment to maintaining the aesthetic integrity of our home. Performance: The mini-split HVAC system has exceeded our expectations. The second floor, which used to be uncomfortably warm during the summer months, is now perfectly cool and comfortable. The system operates quietly and efficiently, providing consistent temperature control without any noticeable increase in our energy bills. The Thielmann Group's recommendation and installation of this system have significantly improved our home's overall comfort and livability. Customer Service: The customer service we received was outstanding. The Thielmann Group kept us informed throughout the entire process, from scheduling the installation to following up afterward to ensure everything was working properly. They genuinely cared about our satisfaction and went above and beyond to make sure we were happy with their service. Overall Experience: I highly recommend The Thielmann Group Heating & Air Conditioning to anyone in need of HVAC services. Their professionalism, expertise, and commitment to customer satisfaction are truly commendable. Our experience with them was nothing short of excellent, and we are thrilled with the results of our new mini-split HVAC system. Thank you, Thielmann Group, for your exceptional service and for making our home a more comfortable place to live!Posted on Gail EllenbeckerJune 22, 2024Trustindex verifies that the original source of the review is Google. Quick, through team
Recent Jobs and Reviews in Oak Creek, WI
Oak Creek, WI at a glance
Thielmann Heating, Cooling & Plumbing has completed 20 jobs in Oak Creek, WI in October 2026.
The most recent job was on October 24, 2026.
Thielmann Heating, Cooling & Plumbing has completed 278 jobs in Oak Creek, WI in the last 12 months.
Job Locations and Reviews
Performed a seasonal tune-up on the HVAC system, including electrical diagnostics with a True RMS clamp meter to verify component readings and inspect the control wiring. Used a digital thermometer to measure system temperatures and confirm proper operation. No visible frost, corrosion, or cracking was observed, and the system was left operating normally.
Installed a new furnace and air conditioning condenser as a complete system replacement, with the electrical work and permits handled for the installation. The refrigerant circuit was evacuated with a digital manifold gauge to a deep vacuum of 387 microns to verify it was leak-free and moisture-free before startup. The furnace was set in the basement with new galvanized supply and return ductwork connected to the plenum, and the equipment and ductwork showed no signs of damage, frost, or corrosion.
Performed a seasonal tune-up on the HVAC system, including inspection of the condensate drain line, which the customer reported had a history of clogging, and verification of proper drainage. Inspected the thermostat and the air handler control board, confirming secure wiring connections with no signs of damage, corrosion, or burn marks.
Installed a new Lennox gas furnace with a new thermostat and condensate pump, reusing the existing filter cabinet and adapting the new unit to the existing PVC venting and condensate drain piping. Connected electrical and gas supply, secured and sealed ductwork connections, and completed the installation under permit with electrical work performed. System was started, tested for proper operation, and verified.
Inspected the exterior wall vent serving the customer's Broan-NuTone ventilation system and found the plastic cover severely cracked and broken, with the wire grille exposed and heavily coated in dirt and debris. Verified the associated flexible and rigid galvanized ductwork in the joist bays and found no significant damage, then evaluated replacement options for the 8"x8" opening to restore proper exterior exhaust termination.
Performed the annual furnace tune-up and inspected the air handler cabinet, gas valve assembly, wiring harness connections, and flame sensor, with no signs of rust, frost, or cracking noted. Removed the dirty, debris-laden pleated air filter and replaced it with a new Secure Aire filter to restore proper airflow.
Performed a complete furnace tune-up, inspecting the burner assembly, gas valve, igniter/flame sensor, inducer motor, wiring, and condensate drain connections. Burners displayed active flame with proper ignition, and no signs of rust, cracking, or frost were found; the system was verified to be operating normally.
Responded to a no-heat complaint where the furnace initiates a heat cycle but shuts off prematurely. Inspected the burner compartment and found significant corrosion on the gas supply piping, gas valve fitting, and cabinet floor, indicating moisture exposure or condensate-related issues. Verified the ignition sequence, flame sensing, and pressure switch/inducer operation to identify the cause of the cycling failure, and documented the corrosion findings with photos for further evaluation.
Performed an on-site estimate for replacement of the furnace and air conditioning system; the existing 24-year-old equipment is operational but at the end of its expected service life. Inspected the outdoor condenser, which shows heavy corrosion on the fan guard and fan hub, a weathered and uneven mounting pad, and debris accumulation around the unit, and evaluated the Carrier gas furnace, ductwork, and surrounding utility space for replacement equipment sizing and installation requirements. Documented equipment conditions with photographs, including the electrical disconnect, flexible conduit connection, and unit data plate, in preparation for system replacement recommendations.
Responded to a hot water boiler heating complaint and inspected the basement-installed boiler system, including the zone valve and actuator wiring, supply piping, and gas piping. Observed heavy corrosion and mineral buildup on piping above the zone valve and rust on the gas line union fitting, both of which are noted as conditions requiring further evaluation. Documented system conditions with photos for the service record.
Responded to a Lennox furnace call-in for a thermostat "125 Control Hardware Failure" code preventing heat operation. Performed electrical diagnostics with a digital multimeter on the control circuit and related components to isolate the cause of the hardware fault. Unit is under the 5-year Lennox warranty coverage.
Performed annual tune-up on gas-fired boiler, inspecting the temperature/pressure gauge, expansion tank, and associated copper and brass piping and fittings, with no leaks, corrosion, or damage observed. Verified the flue venting to the chimney and flexible electrical conduit connections were secure and in good condition, and confirmed the unit was operating normally at completion.
Performed a seasonal tune-up on the 15-year-old gas furnace, removing the access panel to inspect the inducer motor and blower assembly, gas valve, control board, wiring connections, and venting. Noted damp staining on the floor near the unit, which should be monitored for a possible condensate or drainage issue.
Performed an on-site evaluation of the existing 80,000 BTU gas furnace and associated ductwork, documenting equipment dimensions, venting, PVC condensate drain routing, and return/supply airflow (CFM) requirements. Prepared replacement options covering blower motor configurations (including variable-speed) and gas valve staging (single-stage, two-stage, and modulating), providing the homeowner with the information needed to compare repair versus replacement.
Responded to a no-heat call on a 10+ year old gas furnace; verified thermostat operation and call for heat, then performed electrical diagnostics with a multimeter on the control circuit, inducer motor, pressure switch, and gas valve circuit to isolate the cause of failure. Inspected the blower assembly, wiring connections, and burner assembly, which appeared dusty and worn but intact with no visible cracks, rust, or damage. Completed diagnostic testing to determine the fault and restore heating operation.
Installed a matte black two-handle, 8-inch widespread faucet with a matching pop-up drain assembly on the vanity's undermount sink, connecting the supply lines and drain and verifying proper flow and leak-free operation. Inspected the under-sink supply and shutoff valve connections, noting rust staining near the chrome supply fittings and valve, and checked the supply and drain connections for tightness. The jetted tub repair was identified as a separate item requiring further diagnosis.
Performed a furnace tune-up, inspecting the air filter in its housing and finding it in serviceable condition with light, even loading and a minor exposed cardboard edge on the frame. Conducted electrical diagnostics with a true RMS clamp meter, measuring a resistance reading of 54.24 ohms to verify component integrity. The unit was left operating properly at completion of the service.
Responded to a no-heat call on a gas furnace under 10 years old and diagnosed the failure as either the control board or the motor, with the necessary replacement parts sourced from local stock. Inspected the unit with the front panel removed, verifying the burner compartment, control wiring, flue venting, and electrical connections to support the repair and restore heating operation.
Performed a complete furnace tune-up, including inspection and cleaning of key components and verification of safe, efficient operation. Used a digital true RMS clamp meter to test electrical operation, measuring amperage draw and component resistance to confirm the system is operating within manufacturer specifications.
Evaluated the existing upright gas furnace in the basement and assessed repair versus replacement options, noting that the draft inducer motor and blower assembly require replacement although the unit remains operational. Inspected the PVC venting, condensate piping, gas connections, and supply plenum and ductwork, then documented the equipment's condition with photographs to support the replacement estimate.