Considerations for Installing a Gas Cooktop in Your Kitchen

by Michael Chotiner

To begin, let's just say that dropping a cooktop into a precut opening in a countertop and hooking it up to a gas line is pretty easy—about the easiest thing you'll ever do in kitchen remodeling. But planning the space and preparing the countertop and surrounding cabinets for the installation—that's another story. It requires specific knowledge about the dimensions of the cooktop you're planning to put in, attention to the fire code and other clearance requirements and perhaps even a professional tradesperson or two to set things up.

Gas and Electrical Requirements 

Gas cooktops are set up at the factory to operate using natural gas, but most manufacturers also offer propane conversion kits for installations where natural gas isn't available. When planning your installation, provide for a ½-in. rigid gas line with a shutoff valve within 3 ft. of the cooktop location.

You'll also need an electrician to install a breaker-protected, 15-amp electrical circuit terminating in a grounded electric receptacle mounted in the cabinet space beneath the cooktop. This is to power the spark igniters.

If you're simply swapping out an old gas cooktop for a new one of the same size, you've probably got the electric and gas connections you'll need already in place. But if your cooktop is going to go into a new spot in a new or remodeled kitchen, have licensed professionals run the gas and electric supply lines for you.

Sizes and Installation Styles

Generally speaking, you have a choice between 30-in. and 36-in. cooktops—these nominal dimensions refer to the overall length of the burner plate from left to right as the unit is oriented with the front edge parallel to the fronts of the base cabinets. Both 30-in. and 36-in. cooktops are about 21-in. to 22-in. wide, so they fit with margins between the backsplash and front edge of standard 24-in. wide countertops. And all have some depth, which can range between about 3-½ in. and 14 in. The shallower models usually have their controls on top, while the deeper ones typically have controls on the front face.

Dimensions and cutout specs for a Maytag 36-in. cooktop with top controls. Drawing courtesy of Maytag.  

Dimensions for assorted KitchenAid drop-in cooktop models with front controls. Drawing courtesy of KitchenAid

It's important to consider these dimensions and the location of the controls as they affect modifications that will have to be made to the countertop and standard base cabinets to install any given cooktop successfully. For example, when a cooktop has controls on top, it's meant to be dropped into a cutout that's centered between the backsplash and front edge of the countertop; when a unit has controls on the front face, the front edge of the countertop is removed entirely.

Clearances

Gas cooktops can put out a lot of heat, so when planning an installation, it's important to make sure you'll have at least minimum clearances all around the unit to avoid damage to cabinets and wall finishes. Manufacturers' recommended clearances vary, but for planning purposes, use these clearance minimums, which are published in GE's installation instructions for a 36-in. cooktop:

• At least 30 in. from the cooktop to an unprotected cabinet surface directly above. (This leaves space for a range hood, which should be installed above the cooktop.
• At least 6 in. from the edges of the cutout to the side walls of the cabinets into which the cooktop is nestled. (If the cooktop bridges more than one cabinet or vertical dividers, it's acceptable to cut away the tops of the sidewalls to create the required clearances.
• At least 2-¼ in. from the rear wall or cabinet back. (You can cut or remove the cabinet back if necessary.)  

Suggested clearances for a GE 30-in. gas cooktop. Drawing courtesy of GE.

Cutting Countertops  In a best case scenario, the cutout for installing your particular cooktop will have been made by a professional before the top was installed, based on the manufacturer's specifications. Can you do it yourself if you're installing a cooktop in a counter where there hadn't been one before or enlarging an existing cutout for a larger model?

• If the existing top is stone, definitely not—too messy and too risky.
• If the existing top is solid surfacing, maybe, if you think you know what you're doing and have a powerful plunge router and a suitable carbide bit.
• If the existing top is plastic laminate, go for it, if you've got a drill with a ½-in. bit, a portable circular saw with a 40-tooth carbide blade and a jigsaw.

If you want make the cutout yourself, first make a template based on the cooktop manufacturer's size and clearance specs. Lay the template in place on the countertop, and square it up with the front edge of the counter. Transfer your cut lines to the countertop, and clamp or screw some temporary bracing underneath the counter to support the cutout so that it doesn't strain or fall to the floor during the process.

If you're working with solid surfacing, clamp your router guide in place and go to work. If you're working with a plastic laminate top, burnish masking tape over the cut lines to prevent excess chipping when you're cutting with the saws. Start by drilling holes at the corners of the cutout. Then make plunge cuts with the circular saw along each side of the cutout to get as close to the corners as you can. Finish with your jigsaw. If you're installing the type of cooktop that has a burner plate that overlaps onto the countertop, keep in mind that the edges of the cutout don't have to be that straight or smooth.

Installing the Cooktop 

When you have your gas supply (with shutoff in off position), outlet, countertop cutout and the necessary clearances inside the cabinet all in order, you're ready for the easy part. Take the cooktop out of its package and double-check the installation instructions. Find and/or collect all the parts and supplies you'll need to do the gas hookup. They include:

• A pressure regulator
• Two ½-in. flare union adaptors
• A ½-in. flexible appliance connector (not more than 5 ft. long; in Massachusetts, not more than 3 ft. long)
• Brush-on type pipe joint compound or yellow Teflon pipe joint tape
• 3-in. wide reflective foil tape
• Hold-down brackets  

Drawings courtesy of Maytag

• Line the inside edges of the cutout with the foil tape. This prevents heat damage and possible discoloration of the countertop. Lay the cooktop top down on a protected surface.
• Brush pipe-joint compound onto the threads of the manifold entrance—that's the pipe protruding from the bottom or side of the cooktop.
• Thread the pressure regulator onto the manifold entrance, making sure that the flow arrow is pointing toward the cooktop. Tighten it with a wrench.
• Brush pipe-joint compound onto the threads of one of the flare union adaptors and thread it into the open end of the regulator. Make it hand tight and then give it a full turn with a wrench.
• Join the flexible appliance connector hose to the open end of the flare union adaptor after brushing on pipe-joint compound.
• If your cooktop has a glass burner plate, apply foam tape (usually supplied) at the edges on the underside of the cooktop.
• Turn the cooktop right-side up and set it into the cutout. Square it up with the front edge of the countertop.

OK, so next is the hardest part—or let's say it can be a little uncomfortable. Grab the hold-down brackets and screws supplied with your cooktop. Lie on the floor on your back with your head, shoulders and hands in the cabinet underneath the cooktop. Find the spots where the brackets are to be attached to the bottom of the cooktop and screw them in. Then thread in the large screws that secure the assembled unit against the bottom of the countertop. Make it hand tight, and then give it no more than a half-turn with a screwdriver or pliers. Over-tightening these screws can crack stone and solid-surface counters.

With the cooktop bracketed in place, finish up the gas connection:

• Brush pipe-joint compound onto the remaining flare union adaptor and tighten it into the gas shutoff valve.
• Join the free end of the flexible hose connector to the flare union adaptor.
• Turn the gas shutoff valve to ON position.

Test the Gas Connections for Leaks 

Put a drop of dishwashing soap into a small bowl and add some water. Stir it up with a small, clean brush and when you've got some suds, brush the soapy solution onto every joint in the gas connection line from the shutoff valve up to the manifold entrance. If at any point the bubbles show unusual activity, it means you've got a leak. Tighten up those joints and re-test until you're sure that there are no leaks. Then and only then, plug the cooktop's power cord into the outlet.

Finishing Up 

Back on your feet and up top, it's time to assemble the burners. Set each burner head in place, aligning the holes in the bottom with the electrode of the spark igniter. Then place the burner caps on top. Turn each control knob to LIGHT, and after some clicking, each should ignite and produce solid blue flames. If the flames contain a lot of yellow, follow the manufacturer's instructions for adjusting the gas/air mix. Finally, put the grates in place, and the cooktop should be good to go.

About the author:  Michael Chotiner is an expert home-construction DIYer and writes on home appliances, including gas ranges, for Home Depot. Michael's advice on ranges is geared to help homeowners understand the basics of installation. Home Depot's selection of gas ranges can be viewed on the Home Depot website.