Family Values, Quality Comfort
Proudly serving our community with tailored comfort solutions
Advantages
Client Satisfaction
At Old Redwood, we treat our clients like family. Every installation is customized to fit the unique needs of your home and comfort goals. Through honest communication, detailed walkthroughs, and reliable follow-ups, we’re committed to making sure you feel confident and satisfied throughout the entire process.
Accurate
We take pride in fixing problems right the first time. Using thorough diagnostics and proven testing methods, we pinpoint issues accurately and provide reliable, lasting repairs. We believe in measuring, testing, and verifying every step of the process — because quality workmanship should never rely on guesswork.
Our Story
Hi, I’m Justin Korreng, Owner and operator of Old Redwood Heating and Cooling. After 15 years in the HVAC trade, I decided it was time to build something of my own. A company focused on creating a lasting family legacy rooted in honesty quality workmanship, and dependable service.
Throughout my career, I’ve worked in many areas of the industry, from hands on field work to management. Along the way, I developed a deep appreciation for doing things the right way: treating customers fairly, taking pride in quality craftsmanship, and providing solutions that truly fit each customers needs.
That vision became the foundation for Old Redwood Heating and Cooling. My goal was to create a company that values integrity, professionalism, and the skilled tradesmen who serve our community every day. When you call Old Redwood, you can expect straightforward communication, honest recommendations, fair pricing, and work completed with care and precision.
At the end of the day, my mission is simple - to provide a service you can trust and a final product you can feel confident in for years to come.
Our Services
Heat Pumps
Heat pumps are quickly becoming the future of home heating and cooling, offering a cleaner and more energy-efficient alternative to traditional gas systems. Modern heat pump technology has come a long way, delivering impressive cold-weather performance, quieter operation, and greater efficiency than ever before. At Old Redwood Heating & Cooling, we specialize in high-efficiency, inverter-driven heat pump systems tailored to maximize comfort and performance. Our systems operate whisper-quiet and are engineered to provide powerful heating capacity while minimizing reliance on costly auxiliary heat strips.
Dual Fuel
Dual fuel systems combine the energy efficiency of a modern heat pump with the dependable performance of a traditional gas furnace, delivering year-round comfort and flexibility. The heat pump handles everyday heating and cooling efficiently, while the furnace provides powerful supplemental heat during colder temperatures for superior heat recovery and performance.
For homeowners who are not yet fully electric or do not currently have solar to offset energy costs, dual fuel can be an ideal solution. It also offers an extra layer of reliability and peace of mind — if one system requires service, the secondary heat source remains available to keep your home comfortable.
Mini Splits
Mini split systems offer flexible, energy-efficient comfort solutions for homes where traditional ducted systems may not be practical. Whether installed as a dedicated single-zone system or a multi-zone setup for whole-home comfort management, ductless systems provide exceptional versatility and control.
One of the biggest benefits of ductless technology is individualized zone control, allowing homeowners to heat or cool only the spaces being used rather than the entire home. Since each indoor unit operates directly within the conditioned space, mini splits also eliminate the efficiency losses often caused by long or leaking duct runs.
At Old Redwood Heating & Cooling, we design and install customized mini split systems focused on quiet performance, energy savings, and year-round comfort.
Ductwork
Your home’s duct system is one of the most important — and most commonly overlooked — parts of your heating and cooling system. Properly designed ductwork is essential for maintaining comfort, efficiency, and the long-term performance of your HVAC equipment. In many cases, the duct system is what makes or breaks the overall performance of the system.
Undersized ductwork can restrict airflow, making it difficult to properly heat or cool your home while placing unnecessary strain on your equipment through increased static pressure. Over time, this added stress can reduce the lifespan and efficiency of your heating and cooling system. Leaky ductwork can also waste a significant amount of energy by allowing conditioned air to escape into attics or crawlspaces, causing even high-efficiency systems to operate with higher energy costs. In addition, dirty or poorly maintained ductwork can negatively impact indoor air quality, even when high-end filtration systems are installed.
At Old Redwood Heating & Cooling, we carefully inspect every aspect of your duct system and design our ductwork to properly match the airflow requirements of your equipment and the comfort needs of your home. Our goal is to deliver balanced airflow, improved efficiency, cleaner air, and consistent temperatures throughout the entire house.
Repair
When we arrive for a diagnostic, we bring the proper tools, training, and experience to accurately pinpoint the issue and provide a dependable repair solution. We thoroughly inspect critical system components including gas pressure, electrical draw, airflow, refrigerant levels, and more. We don’t replace parts based on guesswork — we identify the root cause and fix it right the first time
Maintenance
Regular HVAC maintenance can make the difference between staying comfortable year-round and experiencing a breakdown when you need your system the most. Routine service helps your equipment operate at peak performance, improves energy efficiency, lowers utility costs, and enhances overall comfort in your home.
During a maintenance visit, we inspect all critical components of your HVAC system — from the equipment itself to the ductwork — to ensure everything is operating in top condition. If we find any areas that need attention, we’ll discuss them with you honestly and professionally. Our goal is to help your system perform at its best without the unnecessary “upselling” that’s so commonly associated with service calls.
Our Projects
Client Testimonials
Megan K
I had an outstanding experience with Justin at Old Redwood H&C. He helped troubleshoot my broken HVAC system and went the extra mile to ensure everything was thoroughly cleaned and fully serviced after fixing all of the issues. He kept me informed every step of the way and was prompt, reliable, and fast. His pricing was very fair and completely transparent, and he was a pleasure to work with. I will absolutely use him for all of my future HVAC needs and highly recommend him!
Scott L
We had Justin from Old Redwood Heating and Cooling replace our entire system including pipes, furnace and A/C. It took him a week to complete our job and each night he left the work area clean, a big plus for us. He worked hard all week and left us with an absolutely great setup for a very reasonable price.
Justin was very friendly and very knowledgeable about all aspects of our job, a plus. Another plus for us was his communication. He kept us informed about everything he was doing and was always willing to answer our questions.
I will not hesitate to give him a call if I need anything else related to heat or A/C for our home.
My wife and I highly recommend Old Redwood Heating and Cooling!
Lynn B
Our HVAC system was over 37 years old and extremely inefficient. The time had come to look into either getting it repaired or replaced. We began to meet with different HVAC companies to begin the bidding process. Not having a lot of knowledge in this field ourselves, we had a lot to learn. Once meeting with Justin Korreng, the owner of Old Redwood Heating and Cooling, we knew we would be doing this project with him. His honesty and knowledge of his trade were like no othtor we'd seen. We could feel his trustworthiness ans passion for his work. The entire project took two days to complete and if we had any questions, he was just a phone call away. We now have an extremely efficient system that was installed with complete transparency.
Old Redwood Heating and Cooling is very highly recommended!!
Frequent Questions
What is your rate?
At Old Redwood, we operate as a flat-rate company, which means no surprises and no hidden costs. You’ll know exactly what the job will cost before any work begins. We also tailor every project to fit your comfort needs and budget. Whether you’re looking for a high-end system replacement or simply need reliable heat and cooling, we have a solution that’s right for you. We also offer Financing through Wells Fargo to make your dream comfort solution that much more attainable.
What brands do you work on?
We service and repair all makes and models of HVAC equipment. With over 15 years of experience in Sonoma County, we’ve repaired, maintained, and serviced countless furnaces, air conditioners, package units, heat pumps, and more.
If you’re unsure about your system or the issue you’re experiencing, feel free to give us a call before committing to a service visit. We’re happy to discuss your system and symptoms to help point you in the right direction. And if we determine that we’re unable to service your equipment, you won’t be charged for the trip.
What kind of certifications do you have?
At Old Redwood, we are fully licensed, bonded, and insured for your peace of mind. We hold a California C-20 contractor’s license for warm-air heating and air conditioning, along with the necessary EPA certifications required to safely handle refrigerants. We also maintain local business licenses for every area we serve.
For system replacements, we partner with EnerGuy to help streamline the process. They assist with permit applications, HERS/ECC testing, and scheduling final inspections to ensure your installation is completed properly and in full compliance with California regulations.