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Why Does Your Convection Oven Take So Long to Preheat?

All convection ovens take some time to preheat, regardless of brand, model, and size. But an electric convection oven shouldn’t take what feels like forever to preheat. So, why does your convection oven take so long to preheat, and what can you do about it?

Your convection oven takes so long to preheat because of inefficiencies. The problem may be the heating elements, temperature sensor, power supply, or air leak. Also, some convection ovens can take a little longer to preheat naturally.

Convection ovens can take 10 to 15 minutes to preheat to 350°F (176.67°C) and up to 30 minutes to reach 500°F (260°C). Any longer than that (or the times specified in your oven’s manual) suggests that there may be a problem. Read on to know why your convection oven takes so long to preheat and how to fix the issue.

Why Your Convection Oven Takes So Long To Preheat

First, check if your convection oven takes longer than the expected time to preheat to certain temperatures. Look at your manual to see the expected durations for different temperatures and preheat modes. Since these are the manufacturer’s specifications, they should be your benchmark for what counts as “normal” as far as your oven is concerned.

Also, the length of time your convection oven takes to preheat depends on several factors. For example:

  • Type. Gas and electric ovens don’t preheat at the same time. 
  • Size. A larger convection oven will naturally take a longer time compared to a smaller one to reach the required temperature.
  • Surrounding temperatures. The ambient heat or cold, relative humidity, altitude, and oven condition will affect the preheat time. 
  • Cleanliness of the oven. A dirty convection oven with grimy heating elements can take longer to preheat than a squeaky clean model. 
  • Design. A convection oven with thicker walls won’t heat as swiftly as those with slender ones. That’s because the former has better insulation, and they retain heat longer. But those thick walls also take more time to preheat. 

Also, some of the latest electric convection ovens have their heating elements inside specially crafted hollow spaces in the walls. These designs are easier to clean. 

If you’ve ever cleaned an old convection oven, you know how tedious it is to get around those heating elements after several rounds of cooking, baking, broiling, or roasting.   

However, concealed heating elements naturally take longer to preheat because they don’t interact as much with the air inside the cavity. While the fan should distribute the heat, you’ll need to wait a little longer for easier cleaning and maintenance.  

Speaking of the fan, your convection oven may have an option to turn off this feature. So, you should check if the convection mode is off when you preheat the oven. Ideally, you should keep the convection mode on whenever you preheat. Otherwise, the oven might take longer to heat. 

Now that I’ve discussed the “normal” factors that cause a convection oven to preheat longer, let me highlight the not-so-normal reasons your convection oven can take absurdly long to preheat.

Your Electric Convection Oven Has Failing Heating Elements

An electric convection oven’s heating elements can be weak, and will gradually fail before they stop working. Therefore, a failing heating component will prolong your preheat cycle. You can clean the heating elements of an electric convection oven, but there isn’t much you can do if they’re worn out or have deteriorated. In that case, you need to replace the inefficient heating elements.  

Hot Air Is Leaking Through the Door Gasket or Hinges

Hot air leaking through the door gasket or seal and hinges will also prolong the preheat cycle. So, check the door to see if it’s misaligned. Then, inspect the gasket or seal, and the door hinges on the two sides. You can replace a leaking gasket or seal and broken or damaged door hinges. 

Also, make sure the oven is on a level surface. Otherwise, you may have a misaligned door. 

In some cases, an oven door can warp. This deformation allows hot air to leak, extending the preheating time. 

The Oven Has a Faulty or Misaligned Temperature Sensor

Temperature sensors go bad. Dirty probes may not accurately detect the temperatures. You may also have frayed or loose connections between the temperature sensor and the thermostat. Any inaccurate sensing can disrupt and prolong a convection oven’s preheat cycle. 

Also, a misaligned temperature sensor will delay the preheating process by shutting the oven prematurely. If the sensor is touching a wall, it can detect a temperature spike even when the cavity or the entire oven isn’t as hot as your selected setting. 

Therefore, the thermostat will shut the oven, then restart the preheat process when the temperature drops.  

Your Convection Oven Doesn’t Have Sufficient Power Supply

Electric convection ovens require a 220V / 240V power connection. Specifically, the appliance needs a steady supply of 2,000 to 5,000 W to operate efficiently. However, this energy requirement differs depending on your model and its size. 

Other power-related factors that can make an electric convection oven take too long to preheat are:

  • Power socket issues
  • Wiring problems
  • Insufficient wattage 

The Convection Oven’s Control Board Has a Fault

The last thing you should check when assessing where the too-long preheating is coming from is the control board. That’s because control boards are pretty pricey, so you should troubleshoot based on the other things I listed previously before you try to replace them. 

Also, control boards don’t go bad completely. Some parts can fail before the entire circuit board goes kaput.

A failing control board can cause fluctuations in the power supply to an electric oven’s heating elements. Similarly, the thermostat can malfunction, leading to inaccurate readings. Control board faults can cause many problems in any connected component of a convection oven. 

Final Thoughts

Convection ovens will take different times to preheat at different temperatures. Also, the mode you choose plays a role in determining how quickly your oven preheats. So, you can try the broil mode for a faster preheat cycle and then switch to roast or bake settings. 

In most convection ovens, the broil heating element and mode reach the highest temperatures. Therefore, using the broil element and mode to preheat for a while before switching to roasting or baking can help you reduce the preheat time for high temperatures.  


  • Steve Rajeckas

    Steve Rajeckas is an HVAC hobbyist with an avid interest in learning innovative ways to keep rooms, buildings, and everything else at the optimal temperature. When he's not working on new posts for Temperature Master, he can be found reading books or exploring the outdoors.

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