Set the oven to 350F, walk away, come back, and the light is still on. If preheat is taking 30 minutes or more, a part is dying. A healthy electric oven with a visible bake element hits 350F in 12 to 15 minutes. Hidden-element models, where the element sits under the oven floor, run a little longer, up to about 20. Most gas ovens land around 20 too. Past that, you are not being impatient. Something is failing.
How long is normal, by oven type
Three numbers to keep straight. Exposed electric element: 12 to 15 minutes. Concealed electric element: up to 20. Gas: around 20. These hold across the brands we see most in Bay Area kitchens, Whirlpool, GE, Frigidaire, Samsung, LG, Maytag, KitchenAid. The design differs but the physics does not.
Electric ovens: the bake element gives out
On an electric oven the bake element carries most of the preheat load. When it starts to go, it still glows and still gets warm, but it cannot pull full wattage. So the oven climbs slowly, or stalls out below your setting.
With the oven cold and the breaker off, look at the element. If one stretch glows during use while another stays dark, or you see a blister, a split, or a bright burn mark, it is partially gone. It does not heal. The broil element up top cycles on during preheat on most electric ovens too, and a weak one loses you the top-down heat that speeds things up.
Element cost runs roughly $150 to $300 installed on common models, more on brands with hard-to-reach elements. Swapping one means disconnecting wiring inside the cavity and seating the connectors right, which is where most DIY attempts go sideways.
Gas ovens: a lazy igniter
Gas ovens use a glow-bar igniter that does two jobs. It heats to light the burner, and it acts as the safety. The gas valve only opens once the igniter draws enough current, which happens when it is hot enough.
Igniters weaken with age and draw less current. The valve still opens, it just takes longer. The tell is the burner taking several minutes to catch instead of the usual 30 to 60 seconds. That is a dying igniter, not a dead one, and it is why the oven still works but crawls. Igniter replacement runs about $180 to $350 installed and puts you near the gas valve and supply line, so it is not a guess-and-check job.
The sensor that lies to the board
Gas and electric ovens both use a thin metal temperature probe at the back of the cavity to tell the control board the real temperature. If that sensor reads low, the oven thinks it is still cold and keeps heating past where it should, or cycles oddly. Food browns unevenly, bake times drift, preheat gets inconsistent even though nothing else changed. A tech tests the sensor resistance against the spec for your model. The part is usually under $100 and one of the more commonly missed causes.
Less common: the control board
The board decides when elements cycle and reads the sensor signal. A failing board might not run elements at full power or might misread temperature. It is the last thing to suspect, only after the element, igniter, and sensor all check out, because boards are expensive and rarely the actual fault.
What to check before you call us
- Gas oven: open the door, start a preheat, watch the bottom. The igniter should glow bright orange and the burner should light within 60 to 90 seconds. Dim glow and a long wait means the igniter is going.
- Electric oven: with the oven cold and off at the breaker, look for cracks, holes, or blistered spots on the element.
- Any oven: put a thermometer in the center, set 350F, and time it. That tells you whether you have a slow-heat problem, an accuracy problem, or both.
If one of those turns something up, you already know what the tech will confirm. Bay Area Appliance Repair Service works most major gas and electric ranges across the Bay Area. Our diagnostic is $75, credited to the repair. Once we find the fault you get a straight repair-or-replace call and a price before we order a thing. Schedule a visit and we will get you on the calendar fast, often same or next day when we can.