Endless Hot Water Starts With a System That Performs Right
Tankless water heaters deliver efficiency and convenience — but they rely on precision components that need proper care to stay reliable. Whether yours needs cleaning, performance testing, or repairs, our technicians provide clear guidance and clean, dependable service.
Why Tankless Systems Need Specialized Care
Tankless water heaters operate differently from traditional tanks. Instead of storing hot water, they heat it on demand — which means every sensor, burner, fan, and flow control has to work perfectly in real time.
Professional tankless service helps:
Maintain steady water temperature
Improve response time
Reduce energy usage
Prevent scale buildup
Extend the lifespan of the system
Minimize noise, errors, and shutdowns
A well-maintained tankless unit keeps your home supplied with reliable, efficient hot water year after year.
Signs Your Tankless System Needs Attention
Tankless units tend to show performance changes before they fail completely. These changes are often subtle but noticeable if you know what to look for.
Service is usually needed when you notice:
Inconsistent or fluctuating water temperature
“Cold sandwich” bursts between hot water cycles
Longer wait times before hot water reaches the tap
Strange noises from the unit
Reduced water flow
Error codes or warning lights
Any of these can signal scale buildup, sensor issues, ignition trouble, or ventilation problems — and our technicians can identify what’s going on quickly.
What to Expect During Tankless Service
Tankless systems run best when each component is clean, calibrated, and functioning as designed. Our service process gives you clarity at every step.
Here’s how we handle your visit:
-
Conversation & System Review
We start by understanding what you’re experiencing — temperature swings, slow heat-up time, or error codes. -
Performance Assessment
We evaluate temperature stability, flow rate, gas/air mixture, ignition, and burner performance. -
Deep Cleaning & Descaling
Hard water scale is the biggest enemy of tankless systems. We flush and descale the unit to restore efficiency. -
Sensor & Control Testing
Flow sensors, thermostats, fan motors, and safety systems are tested for proper communication and operation. -
Clear Results & Recommendations
You get a plain-language breakdown of how the system is performing and what we recommend moving forward.
Every visit ends with a cleaner, more responsive, more efficient system.
Common Tankless Problems We Solve
ankless units are reliable but require precision repairs when something fails. Our technicians diagnose issues accurately and complete repairs with attention to safety and long-term performance.
We repair:
Ignition and burner problems
Flow sensor failures
Venting and airflow issues
Scale buildup causing reduced output
Temperature fluctuation or “cold bursts”
Error codes related to combustion or flow
Fuel or electrical component failures
If a repair is the right move, we’ll tell you. If replacement is smarter, we’ll explain why — without pressure.
Annual Maintenance Protects Your Investment
Tankless water heaters operate continuously with high internal temperatures, which means maintenance isn’t optional — it’s essential. Even small amounts of mineral buildup can affect output, efficiency, and lifespan.
Maintenance typically includes:
Full system flush and descaling
Filter cleaning
Burner and flame inspection
Testing sensors, fans, and ignition
Checking venting and air supply
Verifying temperature accuracy and flow rate
One visit can dramatically improve performance and reduce the risk of shutdowns or expensive repairs.
Why Homeowners Choose Dave’s
Experience You Can Feel
We’ve served Northern Virginia homes for 50 years.
Fair, Upfront Pricing
No upsells, no hidden fees — just straight answers.
Local & Reliable
Based right here in Sterling, ready when you need us.
Respectful Service
We treat every home like it’s our own.
Request Service - It Only Takes 7 Seconds!
Dependable Hot Water to Keep Your Home Comfortable
Dedicated to Your Comfort Since 1975
At Dave’s Heating & Air, we know how important reliable hot water is to your home. Whether we’re repairing your current system or installing a new one, our team takes the same careful, honest approach we’re known for.
We explain what we find, walk you through your options, and outline the cost before any work begins — no surprises and no pressure.
Our technicians take the time to do the job the right way, from clean, precise installations to thorough safety checks on every visit. And because we stand behind our workmanship, your water heater service comes with a written guarantee.
When you choose Dave’s, you get dependable hot water and a team that treats your home with respect every step of the way.
Call 571.346.3940 and let’s keep your home comfortable!
Hear It from Our Happy Customers
Nothing makes us prouder than hearing directly from the wonderful people we serve right here in Sterling, Herndon, Reston and Northern Virginia. Our reputation is built on knowledgeable technicians, courteous service, and the promise that we always leave your home as clean as we found it—if not cleaner!
Customers regularly praise our team for arriving on time, delivering expert system installations and repairs, and ensuring the whole process is seamless from start to finish. Whether it’s a complete HVAC replacement or routine maintenance, folks appreciate the extra care and attention to detail we bring. Many even say they’d recommend us to friends and neighbors without hesitation. Now that’s high praise!
EXCELLENT Based on 116 reviews Posted on Wade McKinnon2025-10-31Trustindex verifies that the original source of the review is Google. Miguel from Dave’s Heating and Cooling is very prompt and efficient. He did our Fall service and performed preventative maintenance. He is a very polite and capable technician.Posted on Max Evangelisti2025-10-24Trustindex verifies that the original source of the review is Google. Excellent customer service from my first phone contact to the site assessment through installation and clean-up, Dave's provided us with expertise and efficiency. The installation crew (Adam, Adam and Jesus) worked quietly and respectfully to minimize disruption. We are very pleased.Posted on Mark Rider2025-10-18Trustindex verifies that the original source of the review is Google. Very professional, helpful and friendly. If you need HVAC repair or maintenance, this is the place.!Posted on Arnold Small2025-10-15Trustindex verifies that the original source of the review is Google. This is a wonderful company to work with. Have used them for years & they offer exceptional service- reliable, instructive & generally very helpful.Posted on Lisa Burke2025-09-29Trustindex verifies that the original source of the review is Google. Our heat went out during the coldest part of winter, and Javier and his team responded immediately. Their professionalism and care made a stressful situation so much easier. We decided to replace both our heating and AC systems, and the quality of service, expertise, and overall experience we received was exceptional. We now have complete peace of mind knowing the job was done right, and we couldn’t recommend them more highly.Posted on BenKim Skehan2025-09-06Trustindex verifies that the original source of the review is Google. Our HVAC went out, and they offered the most affordable replacement by far. They were extremely professional, fast, and efficient—had everything up and running in just a couple of days. Highly recommended!Posted on Craytherine Ciszek2025-09-02Trustindex verifies that the original source of the review is Google. Since 2018 we have counted on the care and expertise of Dave’s team to keep our aging furnaces repaired and running smoothly. Each technician who has come to help has been knowledgeable, respectful and caring. This summer we needed to finally replace one complete HVAC system. Mike O’Neal worked with us using his years of experience in the field to come up with a uniquely tailored plan for our situation. Adam Colbert and his team did a fantastic job with the complex installation. Adam is a caring, confident expert and our system is working perfectly thanks to the knowledge and skills of Mike and Adam. Dave’s is a company to trust for the best HVAC service. Thank you for years of service and heart. The CiszeksPosted on Bobby R2025-08-29Trustindex verifies that the original source of the review is Google. These guys are my new go to for HVAC. We had an issue late day Friday and they got Adam out here to fix it. Adam was fantastic. He figured out the problem in minutes and fixed it right away. Super personable and incredibly friendly. Thank you guys for getting this done so late in the day right before the weekend, and thank you so much Adam for coming out so late on a Friday. Best HVAC experience ever.Posted on Steven Page2025-08-08Trustindex verifies that the original source of the review is Google. Great, fast service! Installed a new hot water heater and heat pump for us this year. Great experience working with a local company!Posted on Tiana2025-08-07Trustindex verifies that the original source of the review is Google. We've had a great experience with Dave's. The technician, Adam, is particularly fabulous. They are prompt, personable and give excellent service.