The short answer
Start with the symptom: no heat anywhere, heat in some rooms only, weak or cool air, strange noises or odors. Each points to different parts, from igniters and thermostats to zone dampers, heat pump defrost controls and ducts, and we diagnose accordingly.
When a Monte Sereno home goes cold, the cause is often not the obvious one. A house with radiant floors, a heat pump upstairs and a furnace downstairs, or zone dampers controlled by a panel in the garage, gives a heating problem many places to hide. EliteAir Heating & Cooling, based about seven miles away in San Jose, repairs heating systems of all common types in Monte Sereno. This page is organized around what you notice in the house, because that is where every repair begins, and then explains what our technicians check for each symptom.
No heat anywhere in the house
A whole-house outage usually points to something central: the thermostat, the power supply to the heating equipment, or a safety control that has locked the system out. Check that the thermostat is on heat with fresh batteries, that the service switch near the furnace or air handler is on, and that no breaker has tripped. If the furnace has a status light, note the blink pattern. A furnace that tried and failed to light several times may sit in lockout until power is cycled, but repeated lockouts mean a part needs attention, usually an igniter, flame sensor or pressure switch.
Heat in some rooms but not others
This is the most common complaint in larger homes, and the fix is often outside the furnace itself.
- Zone damper stuck closed, or a zone control board that has lost communication with one thermostat.
- A duct in the attic or crawlspace that has separated, torn or been crushed during other work.
- A second system serving that wing that has failed while the main one keeps running.
- Closed or blocked registers and return grilles, often behind new furniture or rugs.
- An addition tied into the original ducts without enough capacity to reach it.
Air that feels cool or weak
With a gas furnace, lukewarm air can mean the burners are short cycling on a limit switch because of a dirty filter or a weak blower. With a heat pump, cool air on a chilly morning may be a defrost cycle, which lasts a few minutes, or a stuck reversing valve, which does not go away. Weak airflow everywhere points toward the blower, a clogged filter or a dirty indoor coil.
Heat pumps on the warmer southwestern side of the valley often run hard in summer as well, so a coil that clogged during cooling season can cause poor heating months later. We check both sides of the equipment on every visit.
Noises and odors
Squealing at start-up often comes from a worn inducer or blower bearing. A loud bang when the burners light suggests delayed ignition, which should be checked promptly. Rattling may be a loose panel or a failing motor mount. A dusty smell on the first cold day of the season is normal for a short while; a persistent burning, electrical or gas odor is not.
If you smell gas, leave the home without operating switches and call the gas utility from outside. A repair visit follows once the utility confirms it is safe.
Repair, replace, or plan ahead
Most heating problems are repairable, and we recommend repair whenever the equipment is otherwise in good condition. When it is not, we explain why and lay out the alternatives. Bay Area Air District rules do not require replacing working equipment, but under Rule 9-4 natural gas furnaces manufactured from 2029 must meet a zero-NOx standard. If replacement is getting close, a heat pump that also cools may be worth pricing alongside the repair.
We schedule fall heating inspections across Monte Sereno and nearby Los Gatos, Saratoga, Campbell, Cupertino and Santa Clara. A yearly check keeps igniters, sensors, dampers and defrost controls from surprising you on the first cold night.
More services in Monte Sereno
- AC Repair in Monte Sereno
- Heat Pump Installation in Monte Sereno
- AC Installation in Monte Sereno
- Furnace Repair in Monte Sereno