You set the temperature at 350°F, get going on your preparations, and after twenty-five minutes, there has been no beep. When you’re dealing with an oven taking too long to preheat, it means your dinner will be late since your equipment was supposed to preheat before you chopped everything.
Before you assume your appliance is dead, there’s something worth knowing: an oven taking too long to preheat and a completely broken unit are two different problems pointing to entirely different parts. An oven that won’t heat at all usually has one dead component. On the other hand, an oven taking too long to preheat is usually operating at partial strength, and which component is failing depends almost entirely on whether you have a gas or electric model.
That distinction is what most guides skip, but it’s the fastest route to getting your dinner back on schedule.
Quick answer
In case your oven is taking its time to heat up, there are two likely causes for the problem with an electric one: it could be the heating element that’s not functioning properly or an electrical supply problem. Gas ovens use flames as the source of heat; however, electric ovens need high-voltage heating elements for heating up.
Most Common Causes by Oven Type:
- Electric Ovens: Burnt bake element, missing 240V power leg, or faulty temperature sensor.
- Gas Ovens: Weak igniter unable to open gas valve fast enough.
- For All Types of Ovens: Door seal wear resulting in heat loss or heat absorption due to cookware or a baking stone kept in the oven.
First: How Long Should an Oven Take to Preheat?
If you think your oven never finishes preheating, the very first thing you need to do is see whether you really have some damaged components or just a modern design.
According to manufacturer guidance, expected preheat times to 350°F break down roughly like this:
| Oven type | Normal preheat time |
| Electric with a visible (exposed) bake element | 5–10 minutes |
| Electric with hidden bake element + Fast Preheat | 7–10 minutes |
| Electric with a hidden bake element | 15–20 minutes |
| Gas oven | 15–20 minutes |
That third row surprises people. Hidden bake elements are slower by design. The element sits beneath the oven floor rather than exposed in the cavity, so it has to heat the floor before it heats the air. You gain a cavity that is far easier to clean, and you lose several minutes of preheat. If you replaced a 15-year-old range with a modern hidden-element model and feel your oven taking too long to preheat, nothing is wrong; with the specification changed.
Several other things legitimately add time:
- Every 25°F above 350°F adds roughly 45 to 60 seconds
- Each extra rack left in the oven adds about 30 seconds
- A cold kitchen means a colder starting cavity
- A larger oven cavity are more air to heat
So a 425°F preheat with three racks in a cold January kitchen taking 25 minutes on a hidden-element oven is not a fault. The same oven taking 25 minutes to hit 350°F when it used to take 15 is.
The single most useful question here: has it always been this slow, or did it get slower?
If it has always been slow, you are probably looking at oven design and the fixes in the last section. If it gets slower over time, something is degrading, and the sections below are where you will find it.
If You Have a Gas Oven: Start With the Igniter
This is the cause most articles bury or omit, and it is the one our technicians find most often on gas ovens across Metro Atlanta.
Here is what most people do not realize about how a gas oven lights. The igniter does not just create a spark. It is a resistance device that has to draw enough electrical current to open the gas safety valve. Only when the igniter is pulling roughly 3.2 to 3.6 amps (round style) or 2.5 to 3.0 amps (flat style) will that valve open and let gas flow.
Igniters weaken gradually as they age. A weak igniter will still glow bright orange, but it takes minutes to open the gas valve. So the oven sits there glowing, gas eventually flows, and the burner lights late every single cycle. This gradual degradation is a primary reason for an oven taking too long to preheat, even when everything looks visually fine. The oven still works; it is just slow.
Identifying symptoms: After initiating the oven’s preheat mode and checking inside the oven door, if you notice the igniter taking longer than 90 seconds to spark a flame, it probably needs replacement. There is usually some odor of gas when the ignition first starts, and sometimes it makes a little noise when the flame sparks up.
Reason why it fits the description “it used to be fast”: The igniter wears down over time rather than dying suddenly; therefore, it will get slower and slower over the course of many months.
An igniter is a modest part with a straightforward replacement, but it involves the gas system and should be done by a licensed technician. A glowing igniter is not proof it is good; that is the trap. It has to be tested for current draw, not looked at.
If You Have an Electric Oven: Four Things to Check If Your Oven is Taking Too Long to Preheat
Both the upper and lower heating elements of electric ovens help heat up faster. In case yours takes a lot of time to preheat, follow these four fast tests to determine which one is malfunctioning.
1. The Bake Element Is Failing (Partial Failure)
An electric bake element can fail partially before it burns out completely. A hairline crack, a blistered section, or a spot where the internal coil has thinned means the element still heats but produces far less than its full wattage output. This partial loss of heating power results in an oven taking too long to preheat. It gets there eventually, but takes double the time.
- For Visible Elements: Run a preheat cycle and look directly at the bottom coil. The element should glow an even, bright orange along its entire length. Dark patches, an uneven glow, or visible blistering mean the element is degrading and needs replacement.
- For Hidden Elements: Because the coil sits underneath the porcelain cavity floor, you cannot inspect it visually. These require a technician to perform a continuity and resistance test with a multimeter.
2. You Have Lost One Leg of Your 240V Power Supply
This issue produces a very specific and extremely confusing symptom that catches many homeowners off guard.
An electric range requires 240 volts, delivered through two separate 120V power legs via a double-pole breaker:
- Both legs active (240V): Oven operates at 100% heating capacity.
- One leg lost (120V): Power output drops to roughly 25% (a quarter) of normal capacity.
The Symptom: The oven control board lights up normally, the clock works, and the element even glows dimly, making the appliance look fully operational. However, because it is running on half power, it takes forever to preheat and may never reach higher cooking temperatures.
3. The Oven Is Wired at 208V Instead of 240V
Some residential buildings supply 208 volts rather than standard 240 volts. This is especially common in high-rise condos, townhomes, and converted apartment buildings.
An electric range operating on a 208V supply produces less wattage, resulting in preheat times that are permanently ~25% slower than the same range on a standard 240V supply.
- Important Realization: There is no component repair for this; it is simply a characteristic of the building’s main electrical service. If your oven has always been slow since moving into a condo, knowing this saves you an unnecessary technician call-out fee.
4. The Temperature Sensor Has Drifted Out of Calibration
The sensor placed in the oven cavity senses the air temperature within and informs the control board when to switch on/off the heating elements.
- Principle of operation: The sensors in most of the conventional ovens are resistance type, and their resistance is approximately 1,080 to 1,100 ohms at room temperature (70°F).
- Failure mechanism: With time, the sensors lose calibration because of drift in their resistance. In cases where the sensor shows higher resistance than the actual one, the control board will assume that the oven is already hot.
- Result: The preheating process will take too long to get to the desired temperature or won’t reach it at all.
Fast Free Check: In the oven cavity, inspect the rear wall. If the metal probe is bent and touches the cavity wall, it is measuring the heated metal wall rather than the air temperature. Bend it back into the air to make sure it is not just the probe that is malfunctioning.
4 Causes That Affect Gas and Electric Ovens Alike
Regardless of your oven’s fuel source, a slow preheat can sometimes stem from structural heat loss, mechanical airflow issues, or electronic calibration drift.
1. A Worn or Damaged Door Gasket
The gasket that surrounds your oven door helps keep the thermal energy trapped within the cavity. With a hardened, cracked, flattened or torn gasket, heat loss occurs continuously, making the oven produce extra energy to attain the desired temperature setting.
- Testing the oven: Place your hand along the edges of the oven door when it’s in preheating mode. You will know that the gasket is damaged when you feel any escaping warm air.
- Checking for the hinges: See whether the door is sagging or hanging unevenly. The problem with sagging hinges is that a gap is formed at the top edge that no new gasket can fix.
2. A Worn Control Board Relay
The main electronic control board uses electro-mechanical relays to switch high-voltage power to heating elements or gas ignition circuits. Over time, relay contacts pit and wear down, delivering intermittent or reduced power.
- Note: Because a failing relay mirrors the symptoms of a bad heating element or weak igniter, measuring actual voltage and current draw with a multimeter is critical before replacing parts.
3. The Convection Fan Is Stalled or Seized
Many modern ranges engage the convection fan during the preheat phase to rapidly circulate hot air across the entire cavity. If the convection fan motor burns out, seizes, or gets jammed:
- The rapid air transfer cycle fails completely.
- The oven falls back entirely on passive radiant heating, slowing down the preheat time by up to 30–40%.
4. Temperature Calibration Has Been Shifted
Most digital ovens allow users or technicians to adjust the internal temperature calibration offset (typically up to ±35°F).
If a previous homeowner or technician recalibrated the oven offset low, the control board will operate under incorrect thresholds. Check your owner’s manual for the button combination (often holding the “Bake” or “Settings” button for 5 seconds) to view the current offset and reset it back to 0°F.
The 10-Minute Test That Pinpoints the Problem
Guessing gets expensive quickly. Before ordering parts or calling a repair technician for an oven taking too long to preheat, run this simple diagnostic test to figure out exactly what is happening inside your appliance.
Step-by-Step Diagnostic Test:
- Clear the cavity: Remove every rack except one, leaving it in the center position.
- Place a thermometer: Put an accurate, standalone oven thermometer directly in the center of that rack.
- Start the test: Set the oven to 350°F and immediately start a timer.
- Record time #1: Note the exact time when the oven chime or signal announces it is preheated. Check and record the thermometer reading immediately.
- Record time #2: Leave the door closed and check the thermometer again 10 minutes later.
What Your Test Results Mean:
- Reaches 350°F within the normal time window: The oven is working correctly. Your expectations were likely calibrated to an older, exposed-element appliance.
- Beeps on time, but the thermometer reads well below 350°F: The oven is signaling early, or the sensor is misreading. Many modern ovens chime before the cavity air stabilizes, but a large temperature gap points directly to a drifting temperature sensor or calibration fault.
- Takes far longer than normal, but eventually hits 350°F: You are dealing with a partial power issue, a weakening igniter on gas, or a failing bake element / lost 240V leg on electric.
- Never reaches 350°F at all: There is an active hardware failure. Stop testing and schedule a professional repair visit.
Write the numbers down. Handing a technician “22 minutes to 310°F, then stalled” narrows the diagnosis immediately and shortens the visit.
What You Can Do Yourself, and What Needs a Technician
Although minor fixes such as cleaning sensors and fixing a loose gasket may not take too long, any repair work involving gas leaks, electrical problems, or heating elements needs to be performed by a trained professional.
Safe to do yourself: reset the circuit breaker, remove extra racks, clean heavy grease buildup off the cavity, check the door gasket by feel, verify the calibration offset, and stop relying on the preheat beep by using an oven thermometer.
Call a professional for: anything involving the gas igniter or gas valve, bake element replacement, temperature sensor testing or replacement, control board relay diagnosis, and any oven that trips a breaker, smells of gas, or has visible scorching around wiring.
Two safety notes worth stating plainly. If you ever smell gas, do not troubleshoot; leave the house and call your gas utility. And on any electric oven, power at the breaker comes off before anything is opened.
When to Call Appliance Care of Atlanta?
If your gas or electric oven takes over 20 minutes to preheat, glows without lighting, or fails the 10-minute temp test, schedule an expert diagnosis with Appliance Care of Atlanta today.
- Your preheat time has doubled compared to how the oven used to perform
- The gas igniter glows for more than 90 seconds before the burner lights
- The bake element glows unevenly or has dark sections
- The oven never reaches the set temperature on an oven thermometer
- Resetting the breaker did not help, or the slow preheat returns after a reset
We have serviced ovens and ranges across Metro Atlanta for more than 30 years in Alpharetta, Roswell, Milton, Marietta, Johns Creek, Cumming and the surrounding areas, including gas and electric models from every major brand. We diagnose before we quote, and you approve the price before any work begins.
Call (404) 992-8800 or schedule your oven repair online.
Frequently asked questions
How long should an oven take to preheat to 350°F?
Five to 10 minutes for an electric oven with a visible bake element, and 15 to 20 minutes for a gas oven or an electric oven with a hidden bake element. Models with a Fast Preheat feature typically manage 7 to 10 minutes.
Why does my oven take so long to preheat all of a sudden?
A sudden change points to something degrading rather than a design limit. On gas ovens, a weakening igniter is the most common cause. On electric ovens, look at a failing bake element or a lost 240V leg at the breaker.
Is it normal for a new oven to preheat slower than my old one?
Yes, and it is common. Hidden bake elements are easier to clean but slower to heat, and larger cavities take longer to bring up to temperature. A newer oven taking 15 to 20 minutes is usually behaving exactly as designed.
Can a dirty oven make preheating slower?
Heavy grease and carbon buildup can absorb heat and slow things marginally, but it is rarely the whole explanation. If cleaning the cavity did not restore your old preheat time, the cause is mechanical or electrical.
Does opening the oven door slow down preheating?
Yes. Opening the door releases a large share of the heated air and forces the oven to recover, adding minutes to the preheat. Use the interior light instead of opening the door during preheating.
Should I replace or repair an oven with a slow preheat?
Repair, in most cases. Igniters, bake elements and temperature sensors are individually inexpensive parts and the fix costs a fraction of a new range. Replacement makes more sense when the oven is well past 15 years old and has additional faults.
