Garage door openers for a low ceiling.

Stand inside the garage and look at the wall above the door opening. The horizontal beam across the top of the opening is the header. Now find the first obstruction above and behind it — the ceiling, a joist, a light, a storage rack, a ductwork run. The distance from the floor to that obstruction is your header-to-obstruction measurement.

It is not your ceiling height. A garage with a 10 ft ceiling and a storage platform hung at 8 ft has 8 ft of usable clearance, and the platform is what the operator has to clear.

That difference is not a tuning choice. On the evo+, the control electronics sit inside the ceiling-mounted motor head, so the head is deeper. On the pro+, the control unit mounts separately on the wall and the head is only the motor. Ten inches of clearance, on every track radius.

It is also why the pro+ suits a garage where the ceiling is already committed — racked storage, a car lift, a finished ceiling you would rather not cut into. Programming and day-to-day operation happen at hand height on the wall unit rather than up a ladder.

Below 27 in. you are into the accessory range. These are Sommer parts with their own part numbers, not adaptations.

• GDO connection coupler and curved door arm — connects to the back of the motor carriage rather than the front, recovering 4 to 5 in.
• Low headroom door arm — a shorter arm geometry for tight installations.
• Low profile header bracket — reduces the depth the rail sits below the header.
• Offset bracket — moves the rail line where an obstruction sits directly above the door.
• Side mount kit — mounts the operator to the side of the opening rather than centered above it.

None of these ships with the operator. Tell us the constraint and we will specify the parts with the order.

A low-headroom installation works the operator harder, and Sommer derates it accordingly. Against the standard-radius figures of 600 lb, 1,100 lb and 1,500 lb, a low-headroom installation is rated to 540 lb on the 2060, 990 lb on the 2080 and 1,350 lb on the 2110. A door with poor counter-balance drops further still, to 450, 825 and 1,125 lb.

If your door is close to the standard limit and the installation is low headroom, size up a tier. A door with poor counter-balance should be corrected by a garage door technician before any operator goes on it, whatever the brand.

A jackshaft opener mounts beside the door and turns the torsion bar directly, with no rail above the door at all. If your obstruction sits within roughly 22 in. of the door height, or the ceiling is unusable across its whole span, that is the mechanism you need and no rail-mounted operator will fit.

We carry two: the Chamberlain RJO20 and the Genie B6172H bundle. They are separate from the Sommer range, so the clearance table below does not apply to them. Check each product page for door size and weight limits before you order.

A Sommer side mount is a different thing: the rail is still there, mounted to the side of the opening rather than centered. It solves an obstruction directly above the door. It does not remove the rail.

• Door height and width
• Door weight, or the make and model if you do not know it
• Header-to-obstruction measurement, taken as described above
• Track radius, or a photograph of the track where it curves

Every figure on this page comes from Sommer's published Header to Obstruction and Maximum Door Weights charts. Sommer's own note applies: every job site is unique and must be evaluated individually to confirm the opening can be achieved. Send us the measurements and we will do that with you rather than leave you to interpret a table.