Lambro 1377B Brown Wall Louvered Vent Kit

The Lambro 1377B delivers what HVAC contractors need for code-compliant dryer installations — a complete 4-inch vent kit with UL 2158A listed foil flex duct and an 11-inch aluminum snap-lock tail pipe. Skip it if you’re just patching a bathroom exhaust. This kit’s 257°F operating temperature rating is engineered for dryer heat, both gas and electric.

The brown polymer resin construction solves the curb appeal problem on darker exteriors where white vents stick out like sore thumbs. UV inhibitor in the plastic vent body resists sun fading and brittleness — crucial when Montana’s high-altitude sun beats down on south-facing walls all summer.

Complete Kit Specifications

Contractors appreciate this kit because everything needed for a through-wall installation comes in one package. Here’s what you’re working with:

Specification	Value
Vent diameter	4 inches
Duct length	5 feet
Duct type	Flexible Foil Flex (UL 2158A listed)
Tail pipe length	11 inches
Tail pipe material	Aluminum (snap-lock)
Max operating temperature	257°F
Package weight	12.30 lbs

The included items eliminate multiple trips to the hardware store: one brown plastic louvered wall vent, one 4-inch by 11-inch aluminum snap-lock tail pipe, one 4-inch by 5-foot foil flex duct (UL 2158A), and two 4-inch metal spring clamps.

That snap-lock aluminum tail pipe matters. It creates a secure connection to the vent body without the hassle of crimping or tape. The UL 2158A listing on the foil flex duct means it meets safety and compliance standards for dryer venting — not some generic flex duct that’ll fail inspection.

Installation and Performance Features

Installation requires basic tools: a 4-inch wall saw, screwdriver, caulk, and screws (which aren’t included — plan accordingly). The kit handles standard exterior wall thicknesses with that 11-inch tail pipe and fits standard 4-inch clothes dryer exhaust terminals.

The 3-louvered self-closing design blocks back-drafts and prevents critters from entering. In Montana, that means mice in October, birds in spring, and the occasional curious chipmunk. Those louvers snap shut when the dryer’s off — no manual fiddling required.

The caulk-friendly frame design matters for weather-sealing during installation. You need a solid bead of caulk around that frame to prevent water infiltration during sideways rain or snowmelt running down the siding. The vent body is paintable if you need an exact color match, though proper plastic primer is mandatory or the paint will peel within a season.

Warranty details aren’t explicitly listed by the manufacturer. Retailers typically offer return policies ranging from 30 to 90 days. That’s standard for this category — these aren’t lifetime products.

Montana Climate Considerations

Three features make this kit work in Montana’s weather extremes. The UV inhibitor prevents the plastic from becoming brittle after years of high-altitude sun exposure. Those self-closing louvers keep out wind-driven snow and rain during the eight months when Montana homeowners aren’t running air conditioners. The 257°F temperature rating handles both gas and electric dryers — important in rural areas where propane dryers are common.

While marketed as versatile for bathroom exhaust venting or general moisture removal, it’s really designed for dryer exhaust. The Lambro 264B uses white vinyl duct that’s not suitable for high-temperature dryer venting — it’s the bathroom-specific alternative. Don’t mix them up.

The brown color option matters more than you’d think. White vents on cedar siding or log homes look terrible. This brown option blends with natural wood tones and darker exterior colors common on Montana mountain homes.

FAQ

How thick of a wall can this kit handle? The 11-inch aluminum tail pipe works with standard exterior wall thicknesses. It fits standard 4-inch clothes dryer exhaust terminals. For unusually thick walls, you’ll need to source a longer tail pipe separately.

Does this kit include installation screws? No. Standard wood or metal screws are required but not included. The vent fastens to the wall using screws through pre-drilled mounting holes. Plan on having appropriate exterior-rated screws on hand.

Can this kit be used for bathroom exhaust fans? While secondary applications include bathroom exhaust venting or general moisture removal where a 4-inch duct is required, it’s primarily designed for clothes dryer exhaust venting suitable for both electric and gas dryers. For dedicated bathroom use, Lambro makes the 264B with white vinyl duct specifically for that purpose.

What’s the actual temperature rating? Maximum operating temperature is 257°F. This covers both gas and electric dryers, with room to spare for safety margin.

Do the louvers really keep pests out? The 3-louvered self-closing design blocks back-drafts and prevents critters from entering. The louvers move freely and open when the dryer operates, then close automatically when airflow stops. They’re not pest-proof against determined rodents with time to gnaw, but they prevent opportunistic entry.