The short answer
We repair furnaces, heat pumps, wall heaters, ductless systems and radiant floor heating in Sunnyvale. Diagnosis begins with your specific system and symptom, followed by methodical testing of controls, airflow and the heat source.
Sunnyvale's heating season is short and gentle compared with most of the country, which is part of why heating problems catch people off guard. A system can sit nearly untouched from spring through fall, and then the first damp, chilly week of November reveals that something isn't right. The fix depends heavily on what kind of heating you have. Gas furnaces, heat pumps, wall heaters, ductless mini-splits and in-floor radiant systems all show up in Sunnyvale homes, sometimes two or three in the same house. ReliableAir HVAC Services repairs each of these across 94085, 94086, 94087 and 94089, driving about five miles west from our San Jose base. Rather than repeat a general heating page, here we focus on situations specific to Sunnyvale homes and the questions that help you and our technician get to the cause quickly.
Radiant Floor Heating in Older Homes
Some mid-century Sunnyvale homes were built with radiant heating, where hot water circulates through tubing in the floor slab. These systems are quiet and even when they work, but age brings specific problems: worn circulator pumps, failing zone valves, air in the lines, boiler ignition issues and, in older installations, leaks in the embedded tubing.
We diagnose the boiler, pumps, valves and controls, and can often tell whether a cold zone is a mechanical problem or a sign of a tubing issue. When the slab tubing itself has failed, we'll explain the options honestly, which may include a ductless heat pump for affected rooms rather than costly slab work.
Heat Pumps That Aren't Keeping Up
As more Sunnyvale homes switch to heat pumps, we see more winter calls about them. A heat pump that blows lukewarm or cool air continuously may have a reversing valve stuck in cooling mode, low refrigerant or a thermostat set up for the wrong system type. Outdoor units that ice up and stay iced suggest a defrost control or sensor fault. If your electric bill jumped and the system runs nonstop, the backup heat strips may be doing work the heat pump should be doing.
Quick checks you can do: make sure the outdoor unit is clear of leaves and debris, replace the indoor filter, and confirm the thermostat is set to heat rather than emergency or auxiliary heat.
Problems We See Across All Systems
Regardless of equipment type, a handful of issues account for many heating complaints in Sunnyvale homes:
- Thermostats with dead batteries, lost programming or poor placement near a heat source or drafty door
- Ducts in attics or crawlspaces that have disconnected or lost their insulation
- Clogged filters that trigger safety shutdowns on furnaces and reduce heat pump output
- Wall heater pilots and thermocouples that no longer hold a flame
- Ductless indoor heads with dirty filters and blower wheels that restrict airflow
How Our Technicians Work
We start by listening. When did the problem start? Which rooms are affected? Is there any noise, smell or error code? Then the technician confirms the symptom, checks power and controls, evaluates airflow, and tests the heat source, whether that's a burner, a refrigerant circuit or a boiler. Gas appliances also get a venting and leak check every time.
You'll get a clear explanation of the problem and the repair options before any work begins. Common parts are stocked on our trucks, so many repairs are finished during the first visit. If something needs to be ordered, we'll tell you when to expect it.
Planning Beyond the Repair
Sometimes a heating call reveals equipment near the end of its life. If that's the case, we'll say so plainly. For gas furnaces, it helps to know that Bay Area Air District Rule 9-4 sets a zero-NOx standard for units manufactured from 2029, which steers later replacements toward heat pumps. The rule only applies at replacement and doesn't require removing working equipment, so repair is still a sound choice when your system is in good shape.
More services in Sunnyvale
- AC Repair in Sunnyvale
- Heat Pump Installation in Sunnyvale
- AC Installation in Sunnyvale
- Furnace Repair in Sunnyvale