Search heating repair in San Diego and you get a page of furnace companies. For about half the county that is the right guess. The other half is heated by something that is not a furnace at all, and the diagnosis, the cost, and the trade you want on the roof are all different. So the useful first step is not booking a repair. It is working out what is actually making heat in your house.
Tell us what your heat is doing and we’ll match you with a licensed San Diego HVAC contractor. No cost to you.
Six things heat San Diego houses, and they fail differently
A coastal home here accumulates roughly 1,200 heating degree days a year. Minneapolis runs about 8,000. Because the demand is so low, San Diego never standardized on one heating system the way cold-climate cities did, and the housing stock still carries every approach anyone tried between 1925 and now. Walk four blocks in Golden Hill and you will pass three different answers to the same problem.
| What’s making the heat | Where it turns up | What tends to go |
|---|---|---|
| Ducted gas furnace, attic or closet | 1960s-onward tract housing: Clairemont, Mira Mesa, Tierrasanta, Rancho Peñasquitos | Ignition components, blower motor, rodent-chewed low-voltage wiring |
| Gravity wall heater or floor furnace | Pre-1950 stock: Kensington, South Park, Golden Hill, Mission Hills | Thermocouple, pilot assembly, and eventually the heat exchanger |
| Heat pump, ducted | New construction and most post-2022 changeouts | Reversing valve, defrost control, low refrigerant charge |
| Ductless mini-split head | Retrofits into no-duct housing, coastal remodels, ADUs | Communication faults, condensate blockage, outdoor control board |
| Electric wall heater or baseboard | Condos, 1970s apartments, permitted additions | Element, integral thermostat, tripped breaker |
| Nothing permanent | Older rentals, converted garages, some canyon-lot cottages | This is a code problem rather than a repair |
If yours is a ducted gas furnace, the specifics live on our San Diego furnace repair page, which goes deep on flame sensors, cracked heat exchangers, and when a red tag is real. The rest of this page covers everything else.
Heat pump heating fails in ways people misread as normal
Heat pumps are arriving here fast, pushed by the 2022 energy code and by SDG&E and state rebates. They are genuinely well suited to the climate. But San Diego homeowners have almost no cultural memory of how a heat pump behaves in heating mode, so the early failure signs get shrugged off.
Three patterns are worth knowing. The first is the defrost cycle: on a damp 48°F morning the outdoor unit will steam, stop blowing warm air for several minutes, and sometimes make a loud whoosh when the reversing valve shifts. That is the machine working correctly. It alarms people every winter. The second is the opposite problem, a defrost board that has failed and left the coil iced over, and the tell there is a unit that stays frosted for an hour rather than a few minutes.
The third is the expensive one. Most ducted heat pumps carry electric resistance strips as backup. When the compressor circuit fails, the strips quietly take over and the house stays warm, so nothing seems wrong until the SDG&E bill arrives two hundred dollars heavier. Given that San Diego pays some of the highest residential electricity rates in the country, a heat pump running on strip heat is the most costly HVAC failure in the county that produces no obvious symptom. Check your thermostat for an auxiliary or emergency heat indicator. If it is lit on a mild morning, the compressor is not doing its job.
The old gas heaters, and the one that is not a comfort issue
Gravity wall heaters and floor furnaces are mechanically simple, which is why so many from the 1950s are still lit. Most of what goes wrong with them is small. A thermocouple that no longer holds the pilot open costs a couple hundred dollars to replace. A dirty pilot orifice, a corroded thermostat, a blocked flue where a bird nested over the summer: all fixable, all cheap relative to the equipment.
The exception is a cracked heat exchanger, and it is not a comfort issue. It is a carbon monoxide issue. A floor furnace makes this worse than a closet furnace does, because the grate sits in the middle of a hallway with people standing on it. Parts for units built before 1960 are essentially gone, so when one of these fails a combustion test the real question is what replaces it, not how to fix it. Put a carbon monoxide alarm outside every bedroom regardless. California has required them in homes with fuel-burning appliances since 2011, sealed ten-year units run about $30, and there is no argument on the other side.
When no heat is a code problem instead of a repair
San Diego is a renter-majority city, and a meaningful share of the no-heat calls we see come from tenants being told the wall heater is fine. Worth knowing where the line sits. California treats a dwelling as substandard when it lacks heating facilities capable of maintaining 70°F, and Civil Code section 1941.1 puts the duty to keep those facilities in working order on the landlord, not the tenant. A space heater the owner dropped off is not a permanent heating facility.
If you rent and the heat has been out for weeks, the effective move is usually written notice followed by a call to the City of San Diego’s Code Enforcement Division rather than paying a contractor yourself. None of that is legal advice, and a tenant attorney or the local housing commission will give you a better read on your specific situation than a referral site can.
What it costs, and where the number moves
A diagnostic visit runs $85 to $175 across the county, and most companies credit it toward the repair. The common small jobs cluster tightly: a thermocouple or pilot assembly on an old wall heater lands around $200 to $350, a mini-split condensate or communication fault around $250 to $500, an electric baseboard element or thermostat around $200 to $400. Heat pump work sits higher because the diagnosis takes longer. A defrost board is roughly $400 to $800 installed. A reversing valve is $1,000 to $2,000, and on a system past twelve years old that is the point where replacement deserves an honest look.
Two things move labor more than the part does. Attic access in a 1970s tract house with a scuttle hole over a closet is slow work in a 130°F attic. And a call on the coldest night in late November costs a premium, which is exactly when every marginal heater in the county announces itself at once.
Repairs do not need a permit. Replacing the equipment does, through San Diego Development Services inside city limits and through each jurisdiction’s own department elsewhere in the county, and a changeout on a ducted system also triggers independent HERS duct-leakage testing under Title 24. Whoever does the work should hold a California C-20 license. That takes thirty seconds to check on the CSLB site.
Straight answers
People ask whether a heater that only gets used six weeks a year is worth repairing at all. Generally yes. Low runtime is why heating equipment survives so long in San Diego, and a wall heater that needs a $250 thermocouple is not a candidate for a $9,000 conversation. The exception is any gas appliance that fails a combustion test, where the decision is made for you.
The other frequent question is why a house with heat still has one cold room. That is almost never the heater. In a ducted house it is duct losses into the attic or a run that was undersized when it was installed, and in a no-duct house it is simply that a single wall heater in the hallway was never going to reach a back bedroom. Adding a second head or fixing the duct is the answer, and no amount of servicing the appliance will change it.
And a small one worth checking before anyone comes out: confirm the breaker is on, the gas valve is open, and the furnace door panel is seated. Most units have a safety switch that kills everything if that panel is loose. It solves an embarrassing number of no-heat calls.
Related San Diego HVAC work
For a ducted gas system specifically, see furnace repair in San Diego, or furnace installation when the repair stops making sense. If you are weighing electrification, heat pump installation covers ducted and ductless systems and the SDG&E rate arithmetic behind them. The HVAC in San Diego hub covers the territory as a whole, including how differently the coastal and inland halves of the county behave. You can also browse all HVAC services or browse all services across every trade and city we cover.
Send your San Diego heating repair details
Tell us what kind of heater you have if you know, what it is doing, your neighborhood, and whether you have any heat at all right now. We’ll route it to a licensed contractor who covers your area.