The words greenhouse, polyhouse and tunnel house are often used differently by suppliers and growers. The name is less important than the actual structure and production environment being offered.
Compare frame material, span, anchoring, covering system, doors, side ventilation, insect protection, drainage, irrigation and whether any cooling or automation is included.
A simpler tunnel may be appropriate for seasonal rain protection or crop extension, while a more engineered protected structure may be justified where higher environmental control or larger commercial operation is required.
Request a written scope and BOQ so that quotations can be compared component by component rather than by the headline structure name.