Replacing a microwave takes two to four hours and requires only basic tools—a screwdriver, a level, and a tape measure. Most over-the-range models need an electrician to disconnect the old one safely, but countertop microwaves you can handle yourself. The hardest part is usually removing the old unit without dropping it, not installing the new one.
Key Takeaways
- Over-the-range microwaves are hardwired to your electrical panel and need a licensed electrician to disconnect; countertop models plug into a standard outlet and you can unplug them yourself.
- Measure the space where your old microwave sits before ordering a new one, because even models from the same brand can differ by an inch or two.
- The mounting bracket is the part that holds the microwave to the wall or cabinet—install it level first, then hang the microwave on it.
- Ductwork for over-the-range models vents either outside through your roof or back into the kitchen; check which type you have before installation.
- If you are replacing an over-the-range unit, hire an electrician for the disconnect and reconnect; the cost is usually $150 to $300 and takes one visit.
Measure Your Space and Check the Outlet
Before you buy a new microwave, measure the space where the old one sits. Use a tape measure to get the width, depth, and height of the opening. Write these numbers down—they matter more than the microwave's listed dimensions, because the actual footprint can vary by an inch depending on the model and the trim kit.
For countertop models, check that a standard 120-volt outlet is within reach of the cord. Most countertop microwaves come with a six-foot cord, so the outlet should be no more than that distance away. If you need to use an extension cord, use one rated for the microwave's wattage (usually 1000 to 1200 watts) and keep it as short as possible.
For over-the-range models, you do not need to check the outlet yourself—the electrician will handle that. But you do need to know whether your current ductwork vents outside (through the roof or a side wall) or recirculates back into the kitchen. Look above the microwave in your attic or crawl space, or ask your electrician when they arrive.
Remove the Old Microwave Safely
For a countertop microwave, unplug it from the outlet first. Clear the space around it so you have room to lift. Grab it firmly on both sides—microwaves are heavier than they look, usually 40 to 80 pounds—and lift straight up and toward you. Set it on a sturdy surface or ask someone to help you lower it to the floor. Do not try to carry it down stairs alone.
For an over-the-range microwave, stop here and call an electrician. The unit is hardwired to your electrical panel, and disconnecting it yourself risks electrocution or fire. The electrician will turn off power at the breaker, disconnect the wiring, and remove the mounting bracket. This usually takes 30 to 60 minutes and costs $150 to $300.
Once the old microwave is out, clean the space. Wipe down the cabinet or counter where it sat, and check that the mounting surface is level using a spirit level. If you are installing an over-the-range model in the same spot, the electrician may have already removed the old bracket—if not, unscrew it and set it aside.
Install the Mounting Bracket for Over-the-Range Models
The mounting bracket is a metal frame that bolts to the underside of your cabinet or the wall above your range. It comes with your new microwave and usually includes four to six bolts and washers. Before you touch a drill, hold the bracket up to the wall and use a spirit level to mark where it should sit. The bracket must be perfectly level, or the microwave will hang crooked and the door may not close properly.
Mark the bolt holes with a pencil. Use a drill with a bit slightly smaller than the bolt diameter to make pilot holes—this keeps the bolts from splitting the wood. Insert the bolts through the bracket and into the holes, then tighten them with a wrench or socket. Do not overtighten; snug is enough. The bracket should not move when you push on it.
Check the bracket one more time with the level. If it is not level, loosen the bolts, adjust the bracket, and retighten. This step takes five minutes and saves you from a crooked microwave that you will notice every time you use it.
Hang the Microwave and Connect the Ductwork
For over-the-range models, the microwave hangs on the bracket you just installed. Two metal hooks or a rail on the back of the microwave slot into the bracket. Lift the microwave carefully—get help if you need it—and align the hooks with the bracket slots. Slide the microwave up and back until it sits flush against the cabinet or wall. The bracket should support the full weight; if the microwave feels like it is about to slip, stop and check that the hooks are fully seated.
Once the microwave is hanging, you need to connect the ductwork. If your old microwave vented outside, the ductwork is already in place—you just need to connect the new microwave's duct collar to it. The collar is a metal or plastic fitting on the back or top of the microwave. Slide the duct over the collar and find it with a hose clamp or duct tape. If the ductwork recirculates (vents back into the kitchen), install the charcoal filter that came with your microwave into the filter slot on the bottom of the unit.
For countertop models, there is no ductwork to connect. Just set the microwave on the counter in its final spot and plug it in.
find the Microwave and Install the Trim Kit
Over-the-range microwaves usually come with a trim kit—a metal or plastic frame that covers the gap between the microwave and the cabinet. This is not just for looks; it also keeps steam and cooking splatter from getting into the space above the microwave. Slide the trim kit down from above the microwave and find it with the screws that come in the box. The screws usually go into the sides of the microwave or the cabinet, depending on the kit design.
Check that the microwave is level one final time. If it is tilted, loosen the bracket bolts slightly, adjust the microwave, and retighten. Once you are satisfied, tighten all bolts fully.
For countertop models, no trim kit is needed. Just make sure the microwave is pushed back against the wall or cabinet so it does not tip forward, and that the cord is not pinched or stretched.
Call an Electrician for Over-the-Range Final Connections
If you are replacing an over-the-range microwave, the electrician who removed the old one should return to reconnect the new one. They will connect the wiring to the microwave's terminal block (a set of metal posts where the wires attach), turn the breaker back on, and test that the unit powers on. This usually takes 30 to 60 minutes and is part of the same service call as the removal, so the total cost is still around $150 to $300.
Do not plug in or turn on an over-the-range microwave yourself. The wiring is 240 volts in most homes, and a mistake can cause a fire or serious injury. Wait for the electrician.
For countertop models, you are done. Plug it in, set the clock, and test it with a cup of water for two minutes to make sure it heats.
Common Mistakes to Avoid
The most common mistake is buying a microwave that does not fit the space. Measure twice and compare your measurements to the microwave's dimensions before you order. Some models are listed as "over-the-range" but are actually too wide or too deep for standard cabinet openings.
The second mistake is installing the mounting bracket crooked. A level that is off by even one degree will make the microwave hang at an angle. Spend the extra minute checking it twice.
The third mistake is trying to remove an over-the-range microwave without an electrician. The risk of electrocution is real, and the cost of hiring someone is small compared to the risk. Do not skip this step.
For countertop models, the most common mistake is not securing the ductwork properly. If the duct is loose, steam and grease will leak into the cabinet above the microwave. Use a hose clamp, not just duct tape, to hold the duct in place.
Frequently Asked Questions
Can I install an over-the-range microwave myself without an electrician?
You can install the bracket, hang the microwave, and connect the ductwork yourself. But you need an electrician to disconnect the old wiring and reconnect the new microwave. The electrical part is not optional—it is a safety issue and usually a code requirement in your area.
What if the new microwave is a different size than the old one?
If the new microwave is smaller, you may need a trim kit to cover the gap. If it is larger, it may not fit the space at all. Always measure before you buy. If the new microwave is slightly smaller, the trim kit that comes with it should cover the difference.
Do I need to vent my countertop microwave outside?
No. Countertop microwaves do not produce steam or cooking odors the way range hoods do. They are designed to sit on a counter and do not need ductwork. If you want to use one under a cabinet, make sure there is at least 12 inches of clearance above it for air circulation.
How long does it take to replace a microwave?
A countertop microwave takes 15 to 30 minutes to unpack, set up, and plug in. An over-the-range microwave takes two to four hours total—about one hour for the electrician to remove the old one, one to two hours for you to install the bracket and hang the new one, and another hour for the electrician to reconnect the wiring.
What should I do with the old microwave?
Microwaves contain materials that should not go in the trash. Take it to an electronics recycling center, a scrap metal facility, or a donation center if it still works. Some retailers like Best Buy accept old appliances for recycling when you buy a new one.