Top 6 Mounting Brackets, Flanges & Suspension Kits for Stable Ductwork in the USA — 2025 HVAC Buying Guide for Code‑Aligned, Quiet, and Durable Installations

The Simpson Strong-Tie ATS Seismic Hanger is engineered specifically for seismic and high-movement environments, providing tested lateral and vertical performance that meets stringent building-code requirements. Compared to general-purpose hangers, the ATS commands a premium but offers clear technical value where code-driven seismic performance and documented connectors are required, often eliminating costly design rework and inspection delays in seismic-prone regions.

Simpson Strong-Tie LUS26Z is a heavy-duty joist hanger selected as best-in-class for structural framing because of its engineered load capacity and ZMAX corrosion-resistant coating, backed by extensive design documentation and testing. Compared with the more modular Unistrut and the plumbing-specialist Holdrite, the LUS26Z delivers higher verified shear and uplift capacities for wood-to-wall connections at a competitive price and is widely stocked, reducing lead times and overall project cost for structural wall-bracket applications.

The FHS Free-Standing Spring Hanger from Kinetics Noise Control is a market-leading choice for isolating equipment where support from the slab or structure is required without direct attachment, delivering excellent multi-axis isolation performance for suspended systems. Compared with restrained or neoprene hangers in this list, the FHS reduces transmitted forces to building structures and simplifies isolation of heavy or floor-mounted equipment, which can translate to lower structural reinforcement costs and fewer interface complications. Its design is particularly useful in retrofit scenarios and facilities that prioritize decoupling heavy vibration sources with minimal building modification.

The Broan-NuTone FMR6 is a rugged steel flange mounting ring positioned as a reliable, budget-friendly choice for residential ventilation projects. Its strength and wide availability give it a cost advantage over premium European metal rings while offering greater durability than plastic alternatives like the Vents VKF; however, it trades some corrosion resistance and weight savings compared with aluminum options such as the Master Flow SMF6.

A best-in-class modular strut kit that combines heavy-duty cold-rolled steel channels with pre-engineered fittings for broad suspension applications in suspension rod and grid kits. It earns its position through structural versatility and competitive per-foot material cost compared with cable-based systems like Gripple, making it especially cost-effective for long runs and large projects while being easier to adapt on-site than strictly threaded-rod solutions such as the Cooper B-Line kit.