Santa Teresa sits in South San Jose near the hills, and the microclimate shifts across the neighborhood. Homes closer to the slopes tend to run a little cooler than those on the warmer valley floor, and the side of a house that takes the afternoon sun can run far warmer than the rest of it. We repair, replace and maintain heating and cooling across the 95119 and 95123 zip codes, for homes and for businesses. Most of the problems we see here come back to two things: equipment sized for a different house, and controls that were never set up for the system they run.
Sizing for a variable microclimate
The size of a new air conditioner, heat pump or furnace should come from a load calculation for the house itself: floor area, ceiling height, windows and the way they face, insulation, shade and where the ducts run. Copying the capacity printed on the old unit repeats whatever mistake was made last time.
What goes wrong when the size is off:
- Too big: the system reaches the set temperature fast and shuts off, then starts again minutes later. It cycles all afternoon, wears its parts faster and leaves some rooms warm and others cold.
- Too small: it runs nonstop on the hottest days and still loses ground by late afternoon.
- Right size, wrong ducts: a correctly sized unit on ducts that are too small is noisy and starves the far rooms of air.
For AC installation, furnace installation or a heat pump, we size from the house and check the ducts and the electrical panel before quoting. Estimates for new and replacement systems are free.
Furnace replacement on cool nights
Winters here are mild, but nights near the hills get cool, and the furnace does most of its work in the early morning. When an old furnace fails for good, the choice is usually between a new gas furnace and a heat pump that heats and cools with one system. A heat pump makes the most sense when the air conditioner is also near the end of its life and the electrical panel can take the load. A furnace on its own can be the simpler step when the AC still has years left. If the furnace only needs a part, furnace repair comes first.
Smart thermostats that work as promised
A smart thermostat helps in a house where one side runs warmer than the other: remote room sensors let it average or favor the rooms you actually use, and a schedule keeps the system idle when nobody is home. Most of the trouble we see comes from the installation, not the thermostat itself:
| What happens | Usual cause |
|---|---|
| Screen goes blank or keeps rebooting | No common (C) wire, so the thermostat cannot get steady power |
| Heat pump heats when you ask for cooling | Reversing valve setting wrong (O instead of B, or the reverse) |
| Second stage never comes on | Stage wires not connected or not set up in the menu |
| Fan never stops | Fan set to On rather than Auto, or a wiring mistake |
Thermostat installation checks the wiring and the equipment before the new thermostat goes on the wall, and thermostat not working lists the safe checks you can do first.
Commercial HVAC in Santa Teresa
We also service heating and cooling for businesses in Santa Teresa. Small commercial buildings are commonly served by rooftop packaged units or split systems, and that equipment runs longer hours than a home system, so wear shows sooner:
- belts and fan bearings on rooftop units;
- condenser coils packed with dust and debris;
- economizer dampers stuck open or shut, which either lets warm outside air in on a hot afternoon or wastes free cooling on a cool morning;
- capacitors and contactors that fail in the summer heat;
- thermostats and schedules that no longer match the hours the space is used.
A maintenance visit in spring and again in fall catches most of this before the space gets uncomfortable. See commercial HVAC and rooftop unit service for what a visit covers. Urgent calls are taken 24/7, and you approve the price before we start.
Repairs for homes
Repair calls here follow the season: an AC that stops cooling in a summer heat spell, a furnace that will not light on the first cold morning, a thermostat that goes blank. Most home repairs fall between $89 and $500, the diagnostic fee is waived if you go ahead with the work, and same-day service is available for most calls received before noon. Start with AC repair or the furnace not heating checklist.
We work on all the common makes, including American Standard, Daikin and Lennox. San Jose HVAC Pros is an independent company, licensed, bonded and insured, serving San Jose since 2009.