Heating Repair and Furnace Installation Services
Rely on our certified technicians for prompt heating repairs, efficient furnace installations, and boiler maintenance. High-performance climate engineering for your home.
Expert heating services
Commonwealth Cooling & Heating delivers complete residential heating services in Lorton, Alexandria, and Springfield, VA. Our NATE-certified technicians repair, install, and maintain all furnace, boiler, and heat pump makes and models. We treat every system with engineering precision to ensure peak performance and longevity.
NATE Certified
Fast Response
Precision Heating Systems
Furnace Repair
If your furnace shuts off, blows cold air, or makes clicking sounds, we can help. We diagnose and fix issues with high-tech precision.
Installation
We install energy-efficient gas furnaces and hybrid heating systems that reduce fuel consumption and optimize comfort.
Boiler/Heat Pump
We service boilers and electric heat pumps, ensuring your hybrid systems switch smoothly between fuel sources for maximum savings.
Choosing the right heating efficiency
Compare our systems to find the perfect balance between upfront cost and long-term energy savings for your Northern Virginia home.
| System Type | Efficiency Rating | Fuel Source | Primary Benefit |
|---|---|---|---|
| Standard gas furnace | 80% AFUE | Natural Gas | Low upfront installation cost |
| High-efficiency gas furnace | 95%+ AFUE | Natural Gas | Low operating costs and fuel savings |
| Bryant hybrid heat pump | Up to 11.5 HSPF | Electricity / Gas | Year-round comfort and automated savings |
Need Immediate Assistance?
Our emergency heating teams are standing by 24/7 to restore comfort to your home.
The Physics of Home Heating: Gas Furnaces and Heat Pumps
Home heating systems use combustion or heat transfer to maintain warm temperatures inside during freezing weather.
Gas Furnace Combustion and Heat Exchangers
Natural gas furnaces generate heat through combustion. When the thermostat calls for heat, the gas valve opens, and the burners ignite. The combustion gases pass through the inside of the heat exchanger, heating the metal walls.
The indoor blower fan blows house air across the outside of the heat exchanger, absorbing the heat and distributing it through the ducts. The combustion gases inside the exchanger are vented safely outside.
In standard furnaces (80% AFUE), the exhaust gases are hot and vent through a metal pipe. High-efficiency condensing furnaces (95%+ AFUE) feature a secondary heat exchanger. This secondary exchanger extracts extra heat from the exhaust gases, causing water vapor to condense and allowing the cooler exhaust to vent through inexpensive PVC piping.
The secondary heat exchanger must be made of corrosion-resistant stainless steel. The condensate liquid produced by the secondary exchanger is acidic and must be drained safely through a plastic line.
We check the heat exchanger during maintenance visits. We use small video cameras to inspect the metal walls for cracks. A cracked heat exchanger can leak combustion gases, including carbon monoxide, into your home's air supply.
Heat Pump Technology and Defrost Cycles
Heat pumps operate like air conditioners running in reverse. In winter, a reversing valve changes the direction of refrigerant flow. The system extracts heat from the outdoor air and transfers it inside.
Even in cold weather, outdoor air contains heat energy. However, as the heat pump extracts this heat, frost can form on the outdoor coils. To prevent ice buildup, the system enters a defrost cycle. It temporarily switches to cooling mode to warm the outdoor coil, while activating auxiliary heating coils inside to keep your home warm.
We service gas furnaces, electric heat pumps, and boilers. Our technicians verify burner alignment, combustion safety, and defrost controls to ensure reliable winter heating.
We also test the reversing valve solenoid coil. If the valve fails to switch, the heat pump will stay in cooling mode or heating mode. We verify that the system switches cleanly when the thermostat commands change.
For boilers, we check the water pressure, circulate pumps, and air separators. Air in hydronic lines blocks heat transfer and causes noise. We bleed the lines and balance the valves to ensure even heating across your radiators.
Flame Sensor Diagnostics
Gas furnaces use flame sensors to verify ignition. The sensor uses flame rectification to detect the presence of a flame. It sends a small electrical current through the flame to the control board.
If the sensor is dirty, carbon buildup blocks the current, and the control board will shut down the gas valve after a few seconds. We clean these sensors during tune-ups to prevent sudden furnace shutdowns on cold winter nights.
We also test the hot surface igniter. These components wear out after several heating seasons, and we replace weak igniters to ensure reliable burner ignition.
We verify gas pressure settings. Natural gas systems require proper manifold pressure to burn efficiently. Incorrect gas pressure causes soot buildup on the burners, lowering furnace efficiency.
Auxiliary Heat Strips
Heat pumps require auxiliary electric heat strips to assist during extreme cold. These strips are wire coils that heat up when electricity passes through them.
We verify that the electric strips turn on in stages to prevent electrical spikes on your home's panel. We also test the thermal safety limits, which shut off the strips if the air flow drops too low, preventing fire hazards.
We configure your thermostat to coordinate the heat pump and the electric strips, ensuring you stay warm without using excess electricity.
We also verify the operation of the outdoor sensor, which monitors ambient temperature and commands the electric heat strips to turn on when temperatures drop below the system balance point.
Boiler Hydronic System Balancing
Boiler systems distribute hot water through radiators or baseboard pipes. Over time, air can enter the lines, creating noise and blocking heat delivery.
We inspect the boiler expansion tank and the automatic air vents. We flush the hydronic lines to remove sediment and check chemical levels in the water.
Proper balancing ensures that radiators farthest from the boiler receive the correct amount of hot water, heating your home evenly.
Carbon Monoxide Safety Monitoring
Safety is our priority during furnace inspections. We test the surrounding air for carbon monoxide and check the draft inducer fan operation.
Inducer fans pull combustion gases through the heat exchanger and push them out the vent. If the fan pressure switch fails, the furnace shuts down.
We verify that safety controls are working, ensuring that combustion gases are always vented safely out of your home.
Schedule Heating System Repair
Is your furnace making unusual noises or failing to maintain temperature? Our NATE-certified technicians are on call. Schedule a service visit using the form.
Schedule Repair or Tune-Up
Need immediate cooling, heating, or air filter support? Book a visit from our NATE-certified technicians.
Heat Exchanger Safety and Ignition Systems
The heat exchanger contains combustion gases that heat metal walls. Indoor air passes over the outside, absorbing warmth without mixing with byproducts. If a crack develops, carbon monoxide can leak into your air supply. We inspect using visual checks, combustion analyzers, and temperature differential measurements.
Modern furnaces use electronic ignition: hot surface igniters glow red-hot to light the gas. They eventually crack after thousands of cycles. The flame sensor detects flame by measuring current conducted through it. A dirty sensor causes safety shutdowns. Cleaning with fine abrasive paper is one of our most common fall tune-up repairs.
Heat pump defrost cycles alarm some homeowners. During cold weather, frost builds on the outdoor coil. The defrost board reverses the system temporarily, and steam rises from the unit. This is normal operation, not a malfunction. If cycles run too frequently or not at all, the defrost board or temperature sensor may need service.
