How To Measure A Garage Door For An Opener

How To Measure A Garage Door For An Opener


Installing a garage door opener is a home improvement project that many do-it-yourselfers decide to tackle in an effort to save money and time. Many homeowners believe that the process is as simple as buying the garage door opener that you want, finding the correct installation hardware, and connecting to your existing garage door. While the process is very feasible for homeowners, it involves preparation even before the garage door opener can be purchased.


Matching Your Opener to the Door

One of the most important first steps to installing a garage door opener is to properly measure your garage door so that you purchase the correct size opener for your application. The measuring process is simple and only takes a few tools and about 15 minutes of your time. There are five (5) main measurements to consider.

    1. Height: The height of the garage door opening is the distance from the floor to the top of the garage door opening. This is a very important measurement that determines if you will need an extension kit when purchasing your DIY operator.
    2. Side Room: This is the area available immediately adjacent to the door opening. A minimum of 3.5” to 4.5” is required on either side of the door opening to mount the Safe-T-Beam® System.
    3. Head Room: The head room is the area above the door opening, used to mount the header bracket and rail assembly (you'll want to make sure this area is in good condition). This is measured from the top of the door opening to the ceiling. A minimum of 12” is typically required. 
    4. Depth: This is the distance from the garage door opening to the back wall of the garage. A minimum depth of the door’s height plus 18” is required for manually operated doors, whereas a garage door opener can require the door height plus an additional 3’ to 4’ (for standard 7’ or 8’ high doors, depending on model). Remember that electric motorheads are typically placed 9.5’ to 11.5’ (for standard 7’ or 8’ high doors) from the door, so ensure a 120VAC outlet is within 36” of this location. When measuring the depth, it’s also important to check for any obstructions such as storage, attic access, and beams that may be hanging down in the way of the installation.
    5. Highest Point of Travel: This distance is measured from the ceiling to the highest point of the leading edge of the garage door when being raised. Sectional doors require a minimum of 2.5” for installing of an electric opener.




          Equipped with the measurement information above, you can then begin researching different types of garage door openers that will fit your application. A number of different Genie garage door openers are available, and each has its own set of working parameters.


          Types of Genie® Garage Door Openers

          Genie carries a diverse line of DIY garage door opener units designed to work with single or double doors up to 7’ tall. Extension kits are available for doors that are up to 8’ tall. If purchasing a dealer-installed Genie professional garage door opener unit, the dealer can provide the proper rail (model /drive type specific) for a 7’, 8’, 9’, 10’, 12’, or 14’ residential garage door.

          Genie’s units with 24V DC motors (such as the SilentMax® Connect) have a 500lb. working capacity and are recommended for sectional standard garage doors, and doors with light insulation.

          Doors that are wider and heavier may require installation of a reinforcement bracket to support the additional weight. These doors are often better suited for chain or belt drive units with 140V DC motors and a greater working capacity. These units can handle sectional or one-piece garage doors that are non-insulated or insulated. Doors can be fiberglass, aluminum, or steel without issue.

          Wood doors, double-sided doors with insulation, wind-load rated or hurricane doors, and other heavier door types are best suited for screw drive units with a  140V DC motor. These units work with sectional or one-piece doors.


          Select Genie models and door specifications include:

          • SilentMax® Connect – Smart garage door opener for use with smart phone or device, operates with a quiet 24V DC motor with a 500lb. weight limit for sectional doors. One-piece doors and doors that are over 500lb. will require a special application and a different model unit.
          • Genie Chain Drive 500 – Sports a weight limit of 350lb. and is limited to sectional doors that are 7’ or lower.
          • MachForce® – The top-of-the-line operator that incorporates a screw drive and 140V DC motor. Designed for heavier doors such as wooden doors, Masonite doors, double-sided insulated doors, hurricane doors, and wind-load rated doors.

          Use the Product Selector to find the perfect garage door opener for you.  Make sure to research each type of garage door opener or talk with your dealer to determine the best garage door opener for your particular application. The right equipment can make a world of difference in the performance of your opener, so choose wisely.

          Additional Pre-Installation Considerations

          In addition to considerations made for the size, weight, and style of door, there are a few additional pre-installation considerations to be made.

          • Do you have a finished ceiling? If so, you will need a perforated angle that can span beams of trusses to use for mounting the motorhead.
          • Do you have wood along the door tracks near the floor? This is where the Safe-T-Beam will be mounted. If not, additional fasteners or brackets will be needed for mounting.
          • Is there an electrical outlet within 3’ of the mounting location of the opener? If not, a licensed electrician may need to install one.
          • Is your door in good working condition and balanced correctly? Check the operation of the door and see if any obvious damage or wear needs repaired prior to installing your new garage door opener. Contact a local dealer for door repairs.
          • Finally, are any ropes or locks still connected to the garage door? If so, these will need disconnected or disabled and removed prior to operating with a garage door opener.

          Preparing for the installation of your new garage door opener is not difficult but does take a certain amount of care and attention to detail. With the right amount of forethought, your Genie garage door opener will operate smoothly and consistently for many years to come.

          For more information on Genie garage door opener models, visit our website or contact us today.


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          Is the 500 lb. spec. requirement for the door weight or life force manually from the floor with springs functioning.

          Dale Dobberpuhl

          Number 4 about is wrong: “Depth: This is the distance from the garage door opening to the back wall of the garage. A minimum depth of the door’s height plus 18” is required for manually operated doors,” The back of the garage MAY be a limit, but the mid-70’s Tri-Level houses have a beam running through the garage, typically. This is the limiting factor … which is unfortunately my case (limit 110 inches, currently serviced by a 1997 genie chainglide who’s carriage just broke).

          rod holland

          @Ricky – The garage door height is only the garage door itself. You would not add anything above where the door stops.

          Heather Rothacher

          Is the space between top of the opening and the springs added for the garage height?

          Ricky V Wynkoop

          @Douglas- This depends on which model garage door opener you would like. Please contact Genie customer service at 1-800-354-3643 for assistance.


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