Best Horizontal Vent Kit for Garage Heater

Choosing the right horizontal vent kit for a garage heater ensures safe combustion exhaust, proper draft, and long-term performance. The table below summarizes five top vent kits suitable for garage and shop heaters, covering common diameters and materials used with popular unit heaters and tankless systems.

Product	Diameter / Use	Material / Key Feature
Mr. Heater 4 Inch Stainless Steel Horizontal Vent Kit	4″ – Unit Heaters	Metal kit, complete horizontal venting parts
DuraVent Vent Unit Heater Kit – 4in. Horizontal	4″ – Unit Heaters	4″ horizontal design for unit heaters
CAMPLUX 3″ Horizontal Stainless Steel Vent Pipe Kit	3″ – Tankless Water Heater	Detachable stainless steel, termination hood
DiversiTech HVENT2 2-Inch Horizontal Vent Termination Kit	2″ – High Efficiency Appliances	Low-profile termination, conceals intake/exhaust
Diversitech HVENT-3 Horizontal Term Kit – 3inch	3″ – High Efficiency Appliances	3″ horizontal termination kit

Mr. Heater 4 Inch Stainless Steel Horizontal Vent Kit

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This Mr. Heater kit is designed to provide a complete horizontal venting solution for compatible unit heaters such as the Big Maxx MHU50 and MHU80. The package includes multiple pieces to accommodate through-wall or low-profile installations.

• Included Parts: Adapter, B-vent pipe, two vent pipes, 90° elbow, wall thimble, roof flashing, storm collar, vent cap (9 items).
• Material: Metal components built to withstand heater exhaust temperatures and outdoor exposure when installed per instructions.
• Fitment: Intended for 4″ applications and noted as usable with MHU45 and MHU75 models as well.
• Adjustability: Adjustable elbow and thimble expandability help align through-wall terminations without extensive custom pipe work.

This kit covers the key hardware for installing a horizontal vent run from the unit to the exterior wall, reducing the need to source multiple parts separately.

DuraVent Vent Unit Heater Kit- 4in. Horizontal

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The DuraVent 4-inch horizontal kit is tailored for unit heaters that require 4″ venting. It matches specific DuraVent-compatible heater models, ensuring proper clearances and connection dimensions.

• Design: 4″ horizontal configuration suitable for unit heaters listed in the product compatibility notes.
• Compatibility: Meant for use with several DuraVent item numbers; reference your heater manual for exact fit.
• Simplicity: Focuses on reliable, straightforward connections for unit heater exhaust in through-wall applications.

As a purpose-built kit, DuraVent streamlines installation when used with supported unit heaters and helps maintain manufacturer-recommended vent characteristics.

CAMPLUX 3″ Horizontal Stainless Steel Vent Pipe Kit

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The CAMPLUX 3″ kit is a detachable stainless steel vent system primarily designed for indoor gas tankless water heaters but applicable to small garage heater exhausts that match a 3″ diameter specification.

• Detachable Design: Sections can be assembled to the necessary run length, simplifying tight or offset installations.
• Low Resistance: Engineered to minimize flue gas flow resistance while preventing debris or rain ingress through the termination hood.
• Compatibility: Stated fit for a variety of CAMPLUX models and other 3″ venting applications; confirm diameter match with heater outlet.

The stainless construction provides corrosion resistance, and the termination hood helps protect against weather while maintaining vent performance.

DiversiTech HVENT2 2-Inch Horizontal Vent Termination Kit

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The DiversiTech HVENT2 kit is designed for 2″ high-efficiency fossil fuel appliances, offering a low-profile exterior termination that conceals intake and exhaust pipes for a neat finish.

• Application: Suitable for tankless water heaters, high-efficiency furnaces, and other small combustion appliances requiring 2″ terminations.
• Low Profile Design: Conceals piping for improved aesthetics while maintaining functional venting.
• Dimensions: Listed dimensions provide guidance for wall cutouts and clearances; ensure compatibility with your appliance layout.

This kit emphasizes appearance and compact installation while meeting the functional need to route combustion gases out of an exterior wall.

Diversitech HVENT-3 Horizontal Term Kit – 3inch

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The Diversitech HVENT-3 provides a 3″ horizontal termination solution for high-efficiency appliances. It supports clean, compact exterior exits for intake and exhaust runs.

• 3″ Diameter: Designed for applications requiring a 3″ termination—confirm matching pipe size before purchasing.
• Purpose: Intended to streamline horizontal installations and visually tidy the exterior termination area.
• Installation: Works with standard 3″ vent piping and termination fasteners; check clearance and local code requirements.

This kit is a practical choice when a 3″ horizontal termination is required and when a low-profile, neat external appearance is desired.

Buying Guide: Choosing The Right Horizontal Vent Kit

Selecting a horizontal vent kit for a garage heater requires matching the kit to the heater type, following code, and optimizing for performance and durability. Use the checklist below to evaluate options.

1. Confirm Diameter And System Compatibility

Diameter Matching: The vent kit’s internal diameter must match the heater’s vent outlet (common sizes: 2″, 3″, 4″). Mismatched diameters affect draft and may violate installation instructions.

Appliance Type: Kits designed for unit heaters differ from those for tankless water heaters. Verify the kit manufacturer lists compatibility with your heater or its venting classification (e.g., Category I, III, III+).

2. Material And Corrosion Resistance

Stainless vs. Metal: Stainless steel offers better corrosion resistance, especially in moist garage environments. Painted or galvanized metal may suffice for dry indoor use but can deteriorate faster outdoors.

Weather Protection: Termination hoods, caps, and storm collars reduce moisture ingress. Evaluate whether the kit includes these protective elements for exterior terminations.

3. Horizontal Run Length And Draft Requirements

Equivalent Length: Each elbow, tee, and pipe length contributes to the vent’s equivalent length. Longer runs increase resistance and may require upsizing or adding vertical rise depending on the heater manual.

Manufacturer Specs: Follow the heater’s vent length and elbow count limits. Some heaters require minimum vertical rise or specific elbow types to maintain proper draft.

4. Clearance, Location, And Aesthetics

Clearances: Check clearances to combustibles and required distances from openings, windows, and doors per local code and the heater manual.

Exterior Appearance: Low-profile terminations like DiversiTech HVENT kits hide piping for a cleaner look. Consider paintability and matching the home exterior when aesthetics matter.

5. Installation Features And Included Components

Complete Kits vs. Sections: Complete kits (like Mr. Heater) include elbows, thimble, and caps, reducing part sourcing. Sectional kits (like CAMPLUX) allow custom lengths but may need additional connectors.

Adjustability: Adjustable elbows and expandible thimbles simplify alignment for through-wall installs, minimizing wall modification.

6. Weatherproofing And Debris Protection

Hoods And Screens: Termination hoods and screens are designed to keep rain and debris out while maintaining flow. Kits with integrated hoods reduce the risk of blockage.

Storm Collars And Flashing: For installations that penetrate siding or walls, flashing and storm collars prevent water intrusion and protect structural materials.

7. Codes, Vent Type, And Safety

Local Codes: Confirm local building and mechanical codes governing venting materials, termination locations, and clearances before purchase.

Vent Category: Identify whether your appliance uses Category I, III, or other classified venting; choose products rated for the appropriate category and temperature.

8. Maintenance And Accessibility

Inspection Access: Choose terminations and routing that allow periodic inspection and cleaning. Removable caps or accessible elbows aid maintenance.

Durability: Consider kits with durable fasteners and finishes to reduce long-term maintenance in garage environments exposed to humidity or chemicals.

9. Comparison Perspectives

• Unit Heaters (4″): For typical garage unit heaters, 4″ kits (Mr. Heater, DuraVent) provide full accessory sets and are sized to meet manufacturer vent requirements.
• Tankless / High-Efficiency (2″-3″): For tankless or condensing appliances, 2″ and 3″ DiversiTech and CAMPLUX terminations focus on low-profile and low-resistance designs appropriate for high-efficiency venting.
• Custom Runs: Detachable stainless kits like CAMPLUX allow flexible lengths; complete kits like Mr. Heater reduce parts procurement and ensure matched components.

Before purchasing, cross-reference the selected kit with your heater’s installation manual and local code requirements to ensure a compliant and durable horizontal vent installation.