Trimless vents

A trimless vent, which most buyers call a flush vent, is an air vent with no frame on the surface. Its thin rim is mudded in: finished into the wall or ceiling with joint compound or plaster, so the finished surface runs right up to the opening. HiFi's patent-pending trimless vents fit conventional ducted HVAC and small-duct high-velocity systems, with round, square, linear and patterned faces, in any shape, size or duct connection the job needs.

What makes a vent trimless

A conventional register sits on top of the wall, and its border covers the rough edge of the cut. A trimless vent moves that edge under the finish. Its perforated rim is set against the drywall or plaster, the compound keys through the perforations, and the rim is feathered out like any drywall joint. Once the wall is painted, the room sees the opening and no border around it.

What the opening looks like is a separate choice. Some HiFi faces are a plain round opening or a narrow slot. Others carry one of HiFi's proprietary patterns, such as chevron, hexagon or circles. Full plaster-in faces are finished across with the wall, so only the openings show. Removable faces have a grille that lifts out for cleaning.

Trimless, flush and mud-in

The trade uses three words for this detail. Trimless and mud-in describe the installation: the rim goes under the joint compound, which drywall finishers call mud. Flush describes the result: the face sits in the plane of the wall or ceiling. Some flush vents reach that plane another way, with a plate set into or over the opening. A plate can go over an existing opening with no plastering, and its outline stays on the wall. A trimless vent has no plate, so once the rim is mudded in, the opening is what the room sees.

Where they go

  • Walls and ceilings, conventional ducted HVAC. Catalog vents connect straight to 4, 5 or 6-inch round duct with no register box: round faces, 4x4, 6x2 and 8x2 faces, and a 12-inch linear slot. Register faces fit an existing square or rectangular boot, in catalog sizes from 6x4 and 10x3 to 30x20. Shop traditional HVAC vents.
  • Walls and ceilings, high-velocity systems. 2-inch round, square and hexagon outlets and 6 and 12-inch linear outlets that fit Unico, SpacePak and Hi-Velocity systems. Shop high-velocity outlets or read the high-velocity outlet guide.
  • Floors. A 6-inch linear high-velocity floor outlet, with a long trim that can be sanded flush with wood flooring.
  • Bathrooms. The 4-inch round fixed and magnetic removable models list remote and inline-fan bathroom applications. For a ceiling-mounted fan, HiFi makes a custom flush grille to match it.
  • Anything else. Another size, shape, pattern or duct connection: tell us what you need and we'll make it fit.

Installation

There are two paths, and the stage of the job decides which. The installation guides and videos are grouped by product family.

  • Rough-in, while the wall or ceiling is open. The frame or body mounts to the framing or the board before the surface is closed, and the rim is mudded in with the rest of the wall.
  • Push-through, into a surface that is already finished. The vent goes in through a hole cut in the surface. On the high-velocity outlets the hole size is part of the option you choose: 4-1/4 inches on the 2-inch round, square and hexagon and the straight 6-inch linear, and 3-3/8 inches on some 2-inch round and square options. For other models the cutout is in the model's installation guide or spec sheet.

Hold the frame flush to the board with drywall screws, spray adhesive, or cyanoacrylate glue and activator, then mud over the rim. Pick the lip height for the finish: 1/16 inch for joint compound (mud), 1/8 inch for plaster. Keep the air slots clear, and keep paint and compound out of a removable grille's seam. The plaster-in vent guide goes through the finishing steps.

Choosing one

Make four choices, in this order:

  1. The system. Conventional ducted and high-velocity systems take different connections, so start with the system on the drawings. A similar look in a photograph doesn't mean the same fit.
  2. The connection. The round duct diameter, the register boot size, or the high-velocity connection (a Twist Fit end, or a clamp, tapered or non-tapered end, depending on the model). If the connection you have isn't in the catalog, send it and we'll make the vent to fit.
  3. The stage of the job. Open framing usually means rough-in; a finished surface usually means push-through.
  4. The face. A plain opening or a pattern, fixed or removable, and on removable register faces a grille set flush or inset. A pattern can also be made for the project.

Find your vent narrows the family in a few questions, and the product page confirms the exact model. You can also browse the whole catalog, or start with room ideas in the lookbook.

Airflow

A trimless face changes what the room sees, not how much air the room needs. That figure comes from a room-by-room load calculation (ACCA Manual J) and the duct design that delivers it (ACCA Manual D), and ACCA Manual T covers how supply outlets and returns are chosen and placed. The project's mechanical designer sets the target for each location.

Our linear direct-connect and linear high-velocity families have internal flow paths formed in the body; geometry varies by model. Register faces fit an existing boot. For the figures we have from our CFD models, see the high-velocity outlet guide, or send us the model you plan to specify and we'll send the airflow and pressure-drop information we have for it.

Ordering

HiFi offers a standard catalog of sizes and patterns, along with custom options for project-specific requirements. Orders typically ship within 2-3 weeks. Rush orders are available if your schedule is tight.

HiFi's patent-pending design and manufacturing process can make any shape, size, pattern or duct connection to fit the job. Tell us what you need and we'll make it fit.

Ordering for a whole project? Skip the cart: send us your list in any format, from a spreadsheet to a photo of your notes. We'll match each vent to the catalog, confirm it with you, and send one invoice for the whole order.

Questions

Can I use a trimless vent in a bathroom?

Yes, with a remote, inline or ceiling-mounted fan. The 4-inch round fixed and magnetic removable direct-connect models list remote and inline-fan bathroom applications, with the fan motor elsewhere in the ductwork. For a fan mounted in the ceiling, HiFi makes a custom flush grille to replace the fan's cover, in round, square, linear or a custom pattern, removable for access to the fan's switch and for cleaning, with a plaster-in frame finished into the ceiling. Send us the fan's model number and we'll match it.

Do trimless vents work with central air?

Yes. For conventional ducted heating and cooling, HiFi trimless vents connect directly to 4, 5 or 6-inch round duct, or fit an existing square or rectangular register boot, and other duct sizes are made to fit. Match the duct diameter or the boot size first, then choose the face.

Can I install one in a wall or ceiling that is already finished?

Yes, with a push-through model, which goes in through a hole cut in the finished surface; the rim is then mudded into the surface and painted. Push-through is an installation option on the 6x2 and 8x2 direct-connect vents, the round direct-connect vents, the removable linear direct-connect vent, and the 2-inch round, square and hexagon and straight 6-inch linear high-velocity outlets. Choose it under Installation Type on the product page, and confirm the opening and the finish thickness before cutting.

How is a trimless vent held in place?

With drywall screws, spray adhesive, or cyanoacrylate glue and activator, before the finish goes on. The frame is held flush to the board, and then the rim is finished over with joint compound (mud) or plaster. Rough-in models with mounting holes are mounted with pan-head or cabinet screws. On magnetic removable models, the grille lifts out for access and cleaning.

Can I paint a trimless vent to match the wall?

Yes. Where the model is meant to be painted, use a high-quality bonding primer. Full plaster-in faces take the wall finish across the face, and selected inset grilles can be painted to match the wall or in a contrasting color. Keep the air slots clear and the removable seam free of paint.