Installing an AC Unit in a 1986 Scamp 16'

Objective

Install an air conditioning unit into the cabinet closet next to the door of the 1986 Scamp 16'.

• Camp comfortably in hot weather, especially overnight
• Keep two large dogs cool — they stay in the camper while we’re out hiking

Decisions Made

Space Dimensions

[!tip] Measure Before You Cut Before installing the RVGUARD vent, remove the existing grille and measure the actual hole in the fiberglass body — not just the grille face. This confirms the RVGUARD face will fully cover it and informs how the vent is seated and sealed.

Bill of Materials

Installation Guide

Phase 1 — Assess & Order

• Remove the existing exterior grille and measure the actual hole in the fiberglass body — record W × H
• Confirm the RVGUARD 23-1/8" × 15" face fully covers the measured opening
• Inspect the interior cabinet for any rot, damage, or existing wiring to route around
• Order the RVGUARD vent, LG LW6024R, and all BOM items

Phase 2 — Exterior Vent Replacement

• Remove old grille — typically riveted; drill out rivets carefully to avoid enlarging the fiberglass hole
• Clean the fiberglass surface around the opening; remove any old sealant
• Test-fit the RVGUARD vent; confirm it sits flush (the Scamp body has a slight curve — use butyl tape to conform)
• Run a bead of butyl tape around the interior of the vent flange before pressing it to the body
• Fasten with stainless steel screws or pop rivets through the existing or new mounting holes
• Apply Dicor self-leveling sealant around the full perimeter of the flange on the exterior
• Verify the built-in bug screens are intact after mounting

Phase 3 — Electrical

• Locate the Scamp’s breaker panel and identify an available 15A slot, or confirm the existing outlet circuit has capacity
• Run 12-gauge wire from the panel to inside the closet
• Install a standard NEMA 5-15R outlet box inside the closet, positioned so the LG’s 78" cord reaches without straining
• Test the outlet with a multimeter before use

Phase 4 — Build the Platform

• Measure the wheel well surface inside the closet; cut 3/4" plywood to fit as a platform
• Shim the platform to create a 2–3° backward tilt (toward the exterior wall) so condensation drains toward the drain pan rather than into the closet
• Attach low side rails to the plywood to keep the AC unit from shifting sideways during travel
• Fasten the platform securely to the wheel well or closet floor — it needs to be stable during driving

Phase 5 — Condensation Drainage

• Place the shallow plastic drain pan on the platform, ensuring it sits under the entire footprint of the AC unit
• Drill a ~3/4" hole through the closet subfloor in the lowest corner of the drain pan’s position
• Feed 1/2" vinyl tubing through the hole so it drains to the exterior undercarriage
• Secure the tube with a grommet or sealant at the floor penetration to prevent water wicking

Phase 6 — Install the AC Unit

• Set the LG LW6024R in the drain pan on the platform, back of unit facing the exterior wall and vent
• Wrap Reflectix insulation around the back and sides of the unit, forming a sealed exhaust channel that directs all hot air from the back of the unit toward the RVGUARD vent opening — no gaps
• Tape all Reflectix seams with aluminum foil tape
• Mount the backdraft damper between the Reflectix exhaust channel and the vent opening on the interior side, so it closes when the AC is off
• Secure the AC unit to prevent travel movement: run heavy-gauge wire or ratchet straps over the top of the unit, through or around the closet cabinet structure, and tighten

Phase 7 — Seal & Insulate

• Fill all gaps between the Reflectix channel and the cabinet walls with self-adhesive foam weatherstrip — the goal is zero air path between hot exhaust and cool supply air
• Add a plywood or foam divider above the AC unit inside the closet to fully separate the “AC equipment zone” at the bottom from the clothes-hanging space above — this also prevents cool air from being lost upward into the closet
• Confirm the cord runs cleanly to the outlet without pinching

Phase 8 — Test

• Plug in on shore power; run the unit and verify cold air flows into the cabin
• Hold a hand outside at the RVGUARD vent to confirm hot air is actively exhausting
• Check all Reflectix seams and cabinet gaps for warm air leaks (use the back of your hand)
• Let the unit run 30+ minutes and check the drain pan — confirm condensation is routing out through the floor tube, not pooling or leaking
• Road test: drive around the block, then re-check that the unit hasn’t shifted and all connections are intact

Research & Alternatives

Why This Approach

The 1986 Scamp 16’ pre-dates the era when Scamp reinforced roofs for rooftop AC units. The closet-mount approach is the community standard for pre-2000 models: a window-style unit installed through the existing cabinet opening, with the back ducted to exhaust through the sidewall vent. This is what the factory did on earlier models, and it’s what was previously installed in this trailer.

True through-the-wall (TTW) AC units were considered but ruled out — all standard TTW sleeves are 26"W × 15–16"H (PTAC industry standard), which is too large for the 20"W × 11.5"H Scamp opening without major structural modification.

Sources: Scamp Owners International · Fiberglass RV forum · Soul-Journer build log

[!warning] Effectiveness Note A Scamp service technician noted closet-mounted units “don’t work as well” as roof-mounted units. Performance depends heavily on sealing the exhaust channel — if hot exhaust air can recirculate back to the unit’s intake, efficiency drops significantly. This is why the Reflectix ducting and gap-sealing steps are critical.

AC Unit: Candidates Considered

The binding constraints are height ≤ 11.5" (interior cabinet opening) and depth ≤ 16" (cabinet depth).

The LG LW-series is currently the only in-production window AC line under 11.5" tall in the 5,000–6,000 BTU range. All quieter alternatives are taller or too deep for the 16" cabinet.

Noise caveat: The LG LW6024R has documented fan-rattle complaints that develop over time — a quality-control pattern, not just rated loudness. The LW5025R uses the same chassis. If this becomes a problem after purchase, the fan motor mount and blade balance are the first things to check.

The LG LW6023IVSM (44 dB dual inverter) would be the quieter choice but at 24.52" deep it protrudes 8.5" past the cabinet wall — not workable. The GE AHEL06BB (42 dB) was the quietest unit tested but is discontinued.

Exterior Grille: Alternatives Considered

The existing grille is a return-air style unit — designed for interior HVAC use, not outdoor exposure. It lacks UV rating, drainage channels, and any backdraft protection. However, because positive pressure when the AC runs prevents rain ingress during operation, the practical risk mainly applies when parked with the AC off.

The RVGUARD vent was chosen as a full replacement rather than supplementing the existing grille because: it’s RV-grade UV-resistant polypropylene, includes built-in bug screens, and is sized to cover the opening. The large variant (23-1/8" × 15") fully covers the existing 21.5" × 13.5" grille area with overlap for a clean seal.

Other options evaluated:

• RecPro 24" refrigerator vent — face 24"W × 16.25"H, cutout 21.5" × 13.75". Cutout width matches exactly but the larger face may not lie flat on the curved Scamp body. No bug screen included.
• HVAC exterior gable louvers (HVAC Premium, Byson) — properly weather-rated with 45° blade drainage, available in 20"×20" sizes, but designed for flat static walls — fitment and sealing on curved fiberglass is uncertain.
• Standard TTW grille kits (LG AXSVA4, Frigidaire EA108T) — properly purpose-built with weather seals, but all 26"W — too wide.

Note on backdraft: No available replacement vent in this size range includes a backdraft damper. The plan addresses this by mounting a separate 12"×12" backdraft damper on the interior side of the exhaust channel.

References

YouTube Guides

• Scamp 16’ 1979 Remodel Part 5 — Adding AC to the Closet
• Scamp AC Install
• Installing an AC Unit in a 13ft 1985 Scamp
• Scamp AC Reference

Community & Documentation

• AC Install — Scamp Owners International
• Adding an Air Conditioner — Scamp Owners International
• 16 ft Scamp Window A/C — Fiberglass RV
• How to Install AC on a 16ft Scamp — Fiberglass RV
• Installing AC in the Scamp Closet — Soul-Journer
• Scamp Owners Manual — Appliances

Products

• LG LW6024R — 6,000 BTU Window AC
• LG LW5025R — 5,000 BTU Window AC
• LG LW6023IVSM — 6,000 BTU Dual Inverter
• Honeywell HAC6 — 6,000 BTU Digital Window AC
• RVGUARD Refrigerator Lower/Upper Mount Vent
• RecPro 24" Refrigerator Sidewall Vent
• Low-Profile Window AC Comparison — PickHVAC
• Best 6,000 BTU AC Units — AirconditionerLab