Disconnect the old microwave before you touch anything else
Turn off the breaker that powers your microwave at the electrical panel. If you do not know which breaker it is, flip the main breaker to cut power to the whole kitchen — this is the safest approach. Wait a few seconds, then test the microwave by pressing a button to confirm it has no power.
If your microwave is hardwired (connected directly to the wall with no plug), you will need to remove the wire connections inside the cabinet above or beside it. Take a photo of the wire setup before you disconnect anything so you can match it when you install the new unit. If your microwave plugs into an outlet, straightforward unplug it.
Let the microwave sit for five minutes after power is off. The capacitor inside can hold a charge even when unplugged, and touching it can cause a serious shock. You do not need to open the microwave itself — just wait before moving it.
Key Takeaways
- Turn off power at the breaker and wait five minutes before touching the old microwave, because the internal capacitor holds a charge even when unplugged.
- Take a photo of any hardwired electrical connections before you disconnect them so you can match them when installing the new unit.
- Most over-the-range microwaves are held by a single mounting bracket that bolts to the wall — remove these bolts and the unit will slide out.
- Countertop microwaves straightforward unplug and lift out, but measure the space and check the outlet location before buying a replacement.
- If you are unsure about hardwired connections, hire a licensed electrician rather than guessing — a wrong connection can damage the new microwave or create a fire hazard.
Remove the mounting hardware for over-the-range models
Over-the-range microwaves sit on a metal bracket bolted to the wall studs. Locate the bolts that hold this bracket — they are usually on the sides or back of the unit where it meets the wall. Use a wrench or socket set to remove these bolts. You may need someone to help you support the weight while you work, because these units are heavy and can fall if not held steady.
Once the bolts are out, slide the microwave toward you carefully. The ductwork that vents to the outside may still be connected at the back. If it is, loosen the clamp that holds the duct to the microwave outlet and slide the duct free. Set the old microwave on a sturdy surface or have a helper hold it while you work.
Check the mounting bracket itself. If it is damaged or bent, you may need to replace it before installing the new microwave. Most new over-the-range units come with their own bracket, but confirm this before you remove the old one completely.
Lift out countertop microwaves straight up and away
Countertop microwaves are much simpler to remove. Unplug the cord from the outlet and clear any items sitting on top of or around the unit. Slide the microwave toward the front of the counter to give yourself room to grip it on both sides.
Lift straight up with your legs, not your back. Countertop microwaves weigh between 30 and 50 pounds depending on the model. If you cannot lift it safely, ask someone to help or use a hand truck. Set it down gently on a flat surface so you do not damage the bottom or the power cord.
Measure the space and check the outlet before buying a replacement
Before you shop for a new microwave, measure the width, depth, and height of the space where the old one sat. Write these measurements down. For over-the-range models, also measure the distance from the cooktop to the bottom of the cabinet above — this clearance matters because the microwave needs to sit at a safe height above the stove.
Check where the outlet is located. For countertop models, make sure the new microwave's power cord will reach the outlet without stretching or running under cabinets. For hardwired over-the-range models, note whether the outlet is on the left side, right side, or back of the cabinet space. Some new microwaves have the outlet in a different location than your old one, and you may need an electrician to move the outlet or install a new one.
Look at the ventilation setup. Over-the-range microwaves either vent outside through ductwork or recirculate air back into the kitchen. If your old microwave vented outside, check whether the new one does the same. Switching from vented to recirculating (or vice versa) requires changes to the ductwork and may need a professional.
Install the new microwave in reverse order
For countertop models, this is straightforward: position the microwave in the space, plug it in, and you are done. Make sure it sits level and has at least two inches of clearance on all sides for air circulation.
For over-the-range models, start by installing the mounting bracket according to the manufacturer's instructions. Use a level to make sure the bracket is straight. Bolt it securely to the wall studs — do not use drywall anchors alone, because the microwave is too heavy. If the studs are not in the right location, you may need to install a header board across the studs first.
Slide the new microwave onto the bracket and find it with the bolts provided. Reconnect the ductwork if your model vents outside. If the microwave is hardwired, connect the wires to match the photo you took earlier — typically black to black, white to white, and green or bare copper to ground. If you are uncertain about the connections, stop and call a licensed electrician. Turning the breaker back on with a wrong connection can damage the microwave or start a fire.
Test the new microwave and check for proper operation
Turn the breaker back on at the electrical panel. Wait a few seconds, then press the power button on the new microwave to confirm it turns on. Set it to run for 30 seconds with nothing inside and listen for the fan and the magnetron (the part that generates heat). The fan should run smoothly and the unit should not make grinding or squealing noises.
If the microwave does not turn on, turn the breaker off again and check your electrical connections. If it turns on but the fan does not run, or if it makes unusual noises, turn it off and contact the manufacturer or a service technician. Do not run it repeatedly if something sounds wrong — you could damage the unit or create a safety hazard.
Once the microwave is running normally, test the door seal by closing it and looking for gaps. The door should close smoothly without binding. If it does not, the unit may not be mounted level, or the door itself may be defective. Contact the manufacturer for a replacement if the door does not seal properly.
Dispose of the old microwave responsibly
Microwaves contain materials that should not go in a regular trash bin. The capacitor holds a charge, and the magnetron contains mercury. Many communities have electronic waste collection days or drop-off locations. Check your city or county website for e-waste programs in your area.
Some retailers that sell microwaves also take old appliances for recycling. Call ahead to confirm they accept microwaves and whether there is a fee. If you cannot find a recycling program, a local appliance repair shop may take it off your hands, because they can safely discharge the capacitor and recover parts.
Frequently Asked Questions
Do I need an electrician to replace a microwave?
If your microwave plugs into an outlet, no — you can do it yourself. If it is hardwired and you are not confident about matching the wire connections, hire a licensed electrician. A wrong connection can damage the new microwave or create a fire hazard, so it is worth the cost to get it right.
Can I install a countertop microwave where an over-the-range one was?
Yes, but you will need to cap off the ductwork and either remove the old mounting bracket or cover it with a cabinet. You will also need to find counter space or a microwave cart to hold the new unit. Make sure the outlet is accessible from where you plan to place it.
What if the new microwave does not fit in the old space?
Measure carefully before you buy. If the new unit is slightly smaller, you can use shims or spacers to center it. If it is larger, you may need to modify the cabinet opening or choose a different model. For over-the-range units, you cannot make the space larger without cutting into the cabinet, so stick to models that fit the existing dimensions.
How long does it take to replace a microwave?
A countertop microwave takes 10 to 15 minutes if you are just unplugging and plugging in. An over-the-range model takes 30 minutes to an hour if you are comfortable with basic tools and the ductwork is straightforward. If you need to move the outlet or modify the ductwork, add another hour or more, or hire a professional.
What should I do if the new microwave makes noise?
A small hum from the transformer is normal. A loud buzz, grinding, or squealing usually means something is wrong. Turn it off when ready and contact the manufacturer. Do not keep running it, because you could damage internal parts or create a safety issue.