
Thielmann Heating, Cooling, & Plumbing has serviced HVAC systems for Wisconsin since 1929. Our company is built on the foundation of ensuring the comfort of our customers. Our team of experts provides comprehensive and efficient services for your furnace, air conditioner and heat pumps. In addition to heating and cooling services, we repair, maintain, install and replace plumbing components and systems. We’re your go-to home and commercial utility service provider!
Give us a call at (262) 315-3067 or request a free system estimate online.
Furnace Repairs, Cleaning, Replacement and Installation Services
Is your furnace making loud noises when you turn it on? Is it not cooling your house enough on a hot summer day? Needing furnace repairs is the last thing you need in the middle of winter. These are signs your furnace needs repair:
- Lack of heat
- On and off cycling
- Strange noises
- Fluid leaking
Stay ahead of the cold with our furnace repair and cleaning services. Our technicians inspect your unit and address any issues, all on the same day! With years of experience, there are no furnace issues too complex for us to handle.
Furnaces we install
There comes a time when your furnace will reach the end of its life. If your unit is struggling to keep your home warm, it is time for a replacement! At Thielmann Heating, Cooling, & Plumbing, we specialize in installing the best furnaces for homes in Mequon, WI. We install the following furnaces:
- Gas – Popular choice for energy efficiency and cost-effectiveness.
- Oil – Effective alternative if you don’t have natural gas. More frequent maintenance is balanced by stronger heat output.
- Electric – Simple and efficient, providing a longer life span without as much maintenance. Simplicity comes with higher operating costs.
Heat Pump System Repair, Installation and replacement Services
Heat pumps are great alternatives to furnaces. They provide both heating and cooling capabilities with more precise control. Heat pumps act as a flexible alternative to furnaces. The units allow for dual systems for consistent heating and cooling. They offer all-year comfort while being energy-efficient. Over time, however, your system may show some signs warranting a repair:
- System limited to only heating or cooling
- Heating or cooling slowly
- Sparking or smoking from the unit
While common, these issues leave your heat pump needing to be more efficient. Our experts are available for same-day appointments. We offer comprehensive repairs for all heat pump problems.
When is it time to replace your pump?
If you currently own a heat pump, look for signs that it needs a replacement. The signs include the following:
- Frequent repairs
- Energy bill increases
- Inconsistency in the heating and cooling
Our heat pump installations are quick and efficient, meaning you can get back to home comfort faster.
Contact our team to schedule heat pump services in Mequon by contacting us online or calling (262) 315-3067.
Air Conditioner Repair, Maintenance, Installation and Replacement Services
When the hotter temperatures arrive in Mequon, you need a reliable AC unit. A dependable AC unit provides cool, soothing air when the summer comes. Our technicians at Thielmann Heating, Cooling, & Plumbing are dedicated to ensuring the comfort of your home. Unsure of your AC’s condition? Here are some common signs that your AC system requires some AC repairs:
- Unresponsive thermostats
- Unit is 10+ years old
- Loud or strange noises
- Blowing hot air
Our technicians are available for emergency HVAC service. We will remedy any system issues and secure your comfort. We also provide air conditioner installations and replacements if your system needs more than regular AC repairs or maintenance. If you experience constant AC breakdowns, inconsistent cooling or have a system older than 10 years, you should consider a replacement.

Air Purification & Duct Cleaning Services
Quality heating and cooling are essential for your comfort, as is the air you breathe. Poor air quality can result in frequent allergy symptoms, lingering smells, or even dust accumulation. Experiencing these? You may need a professional air purification service.
Our home purifiers eliminate bacteria that stick to the air, creating a more comfortable and healthier home. The air filters in our purifiers clean your air for six to 12 months before they require a replacement. At Thielmann Heating, Cooling, & Plumbing, we extend our services to clearing your air ducts. Your ducts accumulate debris through continual use. Clearing out this buildup makes the air healthier and your HVAC more efficient. Let us ensure your air is of the highest quality for comfortable, healthier living!
Commercial and residential plumbing services we offer
We’ve designed a range of plumbing solutions to help address diverse challenges. Our qualified plumbing technicians can complete the following:
- Repairs: We can fix faulty plumbing, including components like pipes, fixtures, toilets, water heaters and sump pumps.
- Installations and replacements: Our dependable team can set up new plumbing networks or introduce new components to your existing infrastructure. We install sump pumps, water heaters, fixtures and other components. You can rely on us for installations at your new construction site or replacements of your current plumbing solutions. We can even help you with your kitchen or bath remodel plumbing!
- Maintenance: Proper plumbing maintenance is essential to keeping it operating at its best. Consistent preventive maintenance can help prevent major system issues, reduce your spending on repairs or replacements and keep your property running smoothly. Schedule regular maintenance checks with us, and we’ll care for your plumbing network.
- Water conditioning: For clean, quality and safe water, we offer water conditioning, such as softening, filtration and iron curtain installations and maintenance.
Trusted Mequon, WI Plumbing Professionals
Wisconsin homeowners have trusted Thielmann Heating, Cooling, and Plumbing since 1929 to deliver exceptional, quality plumbing services. We understand how fast a plumbing problem can disrupt your entire routine and how quickly a small problem can turn into a major repair. That’s why we pride ourselves on offering fast, reliable plumbing services in Mequon, WI. Whether it’s a broken pipe, garbage disposal service, on installing a new water heater, we have you covered.
With over 95 years of experience, Thielmann has earned a reputation for honest service and quality workmanship across southeastern Wisconsin. We take the time to explain every repair and give you clear, upfront pricing before work begins. You’ll always know what to expect and why the job matters for your home’s safety and comfort.
Our Mequon plumbing services cover every part of your home’s system:
- Tank and Tankless Water Heater Repair and Replacement
- Drain Clearing and Hydro Jetting
- Water Line Leak Detection and Full Replacement
- Toilet, Faucet, and Shower Fixture Repairs
- Garbage Disposal Troubleshooting and New Installations
- Sump Pump Testing and Backup Unit Setup
- Kitchen and Bathroom Plumbing Upgrades
- Whole-Home Water Filtration and Conditioning Systems
If you hear running water, see signs of leaks, or experience poor water pressure, don’t wait. Call Thielmann Heating, Cooling, and Plumbing at (262) 315-3067 for fast, professional plumbing service in Mequon.
We also complete Commercial HVAC Repair & Maintenance Services
Thielmann Heating, Cooling, & Plumbing’s top-quality HVAC services are not restricted to homeowners. We understand that business owners work hard to provide comfort for their customers. Rely on our experts to provide the highest quality inspections and repairs so your business continues to thrive all year.
Our team is ready to handle any maintenance or repairs for your commercial heating or cooling units. Just need a quick repair? Our team is ready for same-day maintenance work. Let us keep your business at the perfect temperature.
Request a free commercial system estimate or schedule an appointment online today!

Relax in Mequon Knowing Your HVAC System is Running Smoothly
Mequon is a vibrant Wisconsin town with plenty to do and explore! Don’t let your HVAC worries prevent you from a great day in the town. Enjoy peace of mind and explore Mequon’s variety of museums. Learn motorcycle history at the Harley Davidson Museum, find striking pieces of art at the Milwaukee Art Museum, and unleash your wild side at the Milwaukee County Zoo.
Mequon’s attractions cater to everyone, but you can’t enjoy them with HVAC worries on your mind. At the Thielmann Group, we want customers to explore what makes this town great. Take in the sights of the Milwaukee River Walk and come back to a comfortably cooled home from a serviced AC unit. Leave the HVAC problems to us!

Ensure Year-Round Comfort in Mequon with Our Plumbing, Heating & Cooling Services
Thielmann Heating, Cooling, & Plumbing’s reliable services enhance households and businesses for peak comfort. We can transform your home into a cozy shelter from Mequon’s extreme weather. Cool your spaces in the town’s 82-degree summers and keep them warm in the chilly winters! You can rely on us for comprehensive and precise heating and cooling system support and extensive, stress-free plumbing. Let our expert team maintain that comfort for you! Request a free system estimate, schedule an appointment online or call us at (262) 384-6407.
Read Reviews From 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 Mequon, WI
Mequon, WI at a glance
Thielmann Heating, Cooling & Plumbing has completed 20 jobs in Mequon, WI in October 2026.
The most recent job was on October 22, 2026.
Thielmann Heating, Cooling & Plumbing has completed 131 jobs in Mequon, WI in the last 12 months.
Job Locations and Reviews
Inspected two Rheem commercial tank-type water heaters reporting fault codes, verifying the digital control displays, gas control valves, electrical connections, and associated copper and PVC piping. Equipment appeared intact with no frost or rust on the units, though a brown/orange mineral stain was noted on the concrete beneath the pipe fittings, indicating possible minor leakage or corrosion at the connections that should be monitored.
Inspected the Lennox gas furnace and associated supply ductwork in response to reduced airflow at two rooms, verifying sealed duct seams, PVC venting and condensate piping, and gas line connections with no visible damage or obstruction. Noted standing water on the basement floor near the furnace, and recommend further evaluation of the condensate drain and airflow balancing to restore adequate delivery to the affected rooms.
Replaced the failed heat exchanger on the natural gas furnace and restored the unit to proper operation. Post-installation combustion analysis was performed at the flue, confirming safe and efficient performance with a stack temperature of 92.5°F, 94.8% efficiency, CO2 at 4.70%, and CO at 23 ppm, along with an ambient CO check of 0 ppm in the living space.
Performed an on-site assessment for installing a new gas line to a range, evaluating the existing overhead pathway above the drop ceiling and in the basement utility area. Inspected the exposed joist space and surrounding piping, conduit, and ductwork to identify a viable routing path and potential obstructions. Documented existing conditions with photos to support material takeoff and installation planning.
Responded to a no-heat call with a non-powering thermostat and inspected the furnace control board, low-voltage wiring, and terminal connections at the unit. Verified control voltage between R and C, checked for loose or improperly routed thermostat wiring, and tested with a clamp meter to isolate the cause of the power loss to the eco+ thermostat. Corrected the low-voltage wiring issue, restored power to the thermostat, and confirmed proper call for heat and normal furnace operation.
Installed a 3/4" black iron gas line to the stove location, routed through the wall cavity and terminated with a brass fitting and elbow connection to a flexible appliance connector. Sealed the pipe penetration through the framing with foam sealant to close the opening around the line.
Assessed the basement area for installation of a new bar sink, noting an existing floor drain and exposed concrete slab nearby that may serve as a connection point for drainage. Evaluated access for water supply and waste/vent routing and prepared a fixture installation estimate based on site conditions.
Conducted an on-site evaluation for replacement of an existing Carrier WeatherMaker Infinity high-efficiency natural gas furnace located in the basement mechanical area, with an associated Space-Gard air cleaner and galvanized supply trunk. Inspected the PVC vent and condensate piping, noting damp concrete flooring and staining near the condensate drain run and adjacent water treatment tank, and documented existing equipment condition with photos to support the replacement proposal.
Performed a furnace replacement estimate after the heat exchanger failed, requiring the unit to be shut down for safety. Inspected the furnace and surrounding installation, noting heavy rust staining and concrete deterioration near the condensate/drain line termination point at the floor, indicating prolonged moisture exposure. Evaluated the system for replacement and documented conditions with photographs.
Performed a furnace tune-up, inspecting the burner assembly, gas valve, inducer motor, blower housing, pressure switch, and wiring connections, and verifying that the PVC venting and gas piping were secure and free of leaks, corrosion, or damage. The system was found in good operating condition with no deficiencies noted.
Performed a scheduled furnace tune-up under a prepaid maintenance agreement, including removal of the access panel and inspection of the burner compartment, control wiring, and terminal connections. Cleaned the flame sensor to restore reliable flame rectification, and inspected and cleaned the blower wheel to remove accumulated dust and residue for improved airflow and efficiency. Reassembled the unit and verified proper operation.
Assessed the existing sump pit and primary system for the installation of a battery backup sump pump. Inspected the current submersible pump, PVC discharge piping, check valve assembly, and float switch to determine compatibility and placement for the backup unit, and documented pit conditions including sediment buildup and standing water.
Assessed the site for a new gas line to the kitchen range and inspected the existing black iron piping, finding a capped threaded termination within the wall cavity adjacent to the concrete wall. Documented the cap, fittings, and joint condition (including mineral residue at the threads) and marked the pipe routing for the proposed extension, pending verification of capacity and code-compliant installation.
Performed an on-site estimate for replacement of the existing Bryant oil-fired furnace (Beckett burner) with a new oil furnace, inspecting the unit, flue connection, and ductwork, which showed dust and soot accumulation and discoloration. Also evaluated conversion options from oil to LP, since no natural gas service is available at the property, and documented equipment conditions with photos for the replacement proposal.
Inspected the reported leaking exterior spigot and traced the supply line into the adjacent wall framing cavity, where the copper supply piping and fittings were visually examined for signs of leakage, corrosion, or failed connections. Documented the condition of the exposed copper piping and joints, noting the aged finish and surrounding framing, to identify the source of the leak and determine the appropriate repair.
Diagnosed a reported hose bib leak and inspected the associated plumbing fixtures. The toilet tank assembly was also examined, revealing a worn, discolored rubber flapper, a corroded flush chain and lever arm, and mineral buildup on the fill valve and refill tube. Findings were documented with photos for further repair recommendations.
Performed an on-site evaluation for a full system replacement of an aging natural gas furnace located in the basement and a non-operational outdoor air conditioning condenser that has been inoperative for over a year. Inspected the existing furnace, plenum, and ductwork configuration, and documented the condenser, electrical disconnect, and surrounding site conditions, noting heavy vegetation growth around the unit and cracking in the basement block wall. Provided a replacement estimate for a new furnace and AC system.
Inspected the oil-fired furnace equipped with a Beckett burner assembly to verify the completeness of the prior seasonal tune-up and confirm safe operation. Visually evaluated the burner, control wiring, flue connection, and cabinet interior, finding no signs of frost, ice, or significant rust. The unit was found in serviceable condition and ready for heating use.
Conducted on-site evaluation of existing sump pump discharge system to provide estimate for installation of above-ground winter diverter assembly. Assessed current configuration including PVC discharge piping mounted along basement wall with proper bracketing, functional sump pump unit with dual pit covers, and electrical connections. Examined exterior discharge point where sump line exits foundation and terminates at lawn area adjacent to driveway to determine optimal diverter placement and routing requirements for seasonal drainage management. Documented basement installation and exterior discharge location with photographs for estimate preparation.
Responded to no-heat call on heating system over 10 years old with reported hole in unit and carbon monoxide concern. Upon arrival, performed comprehensive system diagnostics using digital multimeter to test electrical components and verify proper voltage readings throughout the control circuit. Measured voltage at burner assembly and control module, obtaining readings of 490-502 volts AC, indicating proper transformer output to gas valve and ignition system. Conducted thorough visual inspection of heat exchanger and burner assembly for cracks, holes, or deterioration that could allow carbon monoxide leakage into living space. Examined all accessible sections of heat exchanger, flue pipe connections, and combustion chamber for structural integrity. Inspected flexible flue coupling and metal clamp connections for proper seal and secure attachment to white cylindrical vent pipe. Tested all safety controls including limit switches, flame sensor, and pressure switches to ensure proper op