## Rooftop AC

## Rooftop AC

by 3M

Medium Install Climate Control Model: SM600L

About This Part

Product Name: Dometic Freshjet 2 RTX 1350 Air Conditioner 13,500 BTU cooling, 100120V, single zone Ultraquiet, ducted, heat pump option available Wireless remote, variable speed fan Description: The Dometic Freshjet 2 RTX 1350 combines strong cooling with a compact, lightweight design and quiet operation, making it a top choice for modern campervans. It splits the compressor and air handler to reduce cabin noise and maximize airflow. ## Espar Product Name: Espar Airtronic S3 D2L Diesel Air Heater Diesel fuel, 12V, 7,500 BTU (2.2 kW) output Altitude adjustment up to 13,000 ft Description: The Espar S3 D2L delivers efficient, dry warmth for vans, ideal for cold climates, with included parts for a clean install. Its low power draw and altitude capability make it a favorite for overlanders. ## Maxxfan Product Name: Maxxair Maxxfan Deluxe (with remote) 10speed fan with rain cover, reversible airflow Builtin thermostat, remote control, smoke function 12"14" roof cutout required, 12V Description: The Maxxfan Deluxe is a top pick for campervan ventilation, offering quiet, powerful airflow, rain protection, and convenient remote control, making it a staple for van conversions. ## Electric Heater Product Name: Propex HS2211 Portable Heater Propane (no 12V/120V option), 7,100 BTU output Thermostat, low voltage cutoff, safety features Includes flexible duct and mounting options Description: The Propex HS2211 is a reliable forcedair propane heater, ideal for vans with existing propane systems, offering efficient heat with builtin safety features. ## Thinsulate Product Name: 3M Thinsulate SM600L Automotive Insulation Cascadia Veh

Where to Buy

Official Product Page: https://www.3m.com/3M/en_US/insulation-us/
Documentation: View Specs & Manual
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Installation Information

Installation Difficulty: Medium

Van Compatibility: Universal fit—requires propane line, flexible install for Sprinter/Transit/ProMaster[3]

Buying Guide

I don't have information available about a rooftop AC unit made by 3M for campervan and RV conversions. The search results provided do not contain any products manufactured by 3M - instead, they show air conditioning units from brands like Velit, Anchor Group, Dometic, and Nomadic Cooling.

3M is primarily known for manufacturing adhesives, abrasives, and various industrial products, but they are not a recognized manufacturer of RV or campervan air conditioning systems. It's possible you may be thinking of a different brand or model.

If you're looking for guidance on rooftop air conditioners for campervan conversions, I'd be happy to help you with information about the actual brands that manufacture these systems, such as:

  • Velit (offering DC-powered units like the 2000R and 3000R models)
  • Dometic (a leading RV appliance manufacturer)
  • Nomadic Cooling (specializing in van life climate control)
  • Various other manufacturers shown in the search results

Could you clarify which specific brand or model you're interested in learning about? This would allow me to provide you with accurate, detailed buying guidance for the correct product.

Product Comparison

A rooftop AC unit is the most common and space-efficient air conditioning solution for campervans and RVs, offering high cooling power and seamless integration[1]. Here’s how it compares to leading alternatives:

1. Coleman Mach 15 by Airxcel
- Pros:
- High cooling capacity (up to 15,000 BTU), suitable for large vans and hot climates[4].
- Rugged build and widely available replacement parts.
- Often comes pre-installed in many new RVs.
- Cons:
- Traditional models are 120V, requiring shore power or a large inverter[2].
- Can be noisy on high settings[1].
- Draws high starting amperage.
- Price Range: \$1,200–\$1,500.
- When to Choose: Select for maximum cooling in hot climates with regular access to shore power.

2. RecPro RP-AC3800
- Pros:
- 15,000 BTU rating, matching the top tier for rooftop units[4].
- Includes a remote control and heat pump feature for supplemental heating.
- Easier DIY installation with all needed parts included[4].
- Cons:
- Slightly less efficient cooling than top competitors.
- Remote has limited range[4].
- Price Range: \$1,100–\$1,400.
- When to Choose: Good for comfort-focused conversions prioritizing installation ease and dual heating/cooling.

3. Velit 2000R 12V Rooftop AC
- Pros:
- Runs on 12V DC: ideal for off-grid and battery-powered van builds[3][5].
- Low power draw (20–60A), very efficient for boondocking[3][5].
- 8,000 BTU output; lightweight.
- Cons:
- Lower cooling output than 120V rivals; best for well-insulated, smaller vans.
- Newer market presence, so less established support[3].
- Price Range: \$1,500–\$1,700.
- When to Choose: Choose for off-grid living, small/medium vans, and battery-focused electrical systems.

4. Dometic FreshJet Series
- Pros:
- Multiple size options: 2,000–15,000 BTU[6].
- Reliable and globally supported brand.
- Slim design for maximizing solar panel space.
- Cons:
- Higher prices for top models.
- Heavier and may require professional install[6].
- Price Range: \$1,400–\$2,000.
- When to Choose: Suited for those seeking established reliability and international travel.

Performance and Use-Case Comparison

| Product | Power Source | BTU Range | Best For | Typical Price |
|-----------------------------|--------------|---------------|---------------------------------------|-----------------|
| Rooftop AC (General) | 120V/12V | 13,500–18,000 | Overall efficiency, best for large RVs| \$1,100–\$2,000 |
| Coleman Mach 15 | 120V | 15,000 | Max cooling, big rigs, site hookups | \$1,200–\$1,500 |
| RecPro RP-AC3800 | 120V | 14,500–15,000 | DIY ease, remote/heat pump features | \$1,100–\$1,400 |
| Velit 2000R 12V | 12V | 8,000 | Off-grid vans, solar/battery setups | \$1,500–\$1,700 |
| Dometic FreshJet | 120V/12V | 2,000–15,000 | Global service, slim/versatile design | \$1,400–\$2,000 |

  • Van Life Notes: For constant off-grid living, 12V models like Velit or CountryMod are best due to efficiency and low inverter loss[2][5]. For hookup-based or large-rig touring, high-BTU rooftop models like Coleman or RecPro excel via sheer cooling output and multi-zone potential[1][4][6].

Choose rooftop ACs when you need space-saving, integrated appearance, and maximum cooling output for van life, especially in hot weather or larger vehicles[1]. Opt for 12V options if off-grid, battery-only operation is a priority.

Installation Tips

Tools Required

  • Drill (with metal cutting and drill bits)
  • Jigsaw or angle grinder (for cutting roof)
  • Screwdrivers and socket/wrench set
  • Safety goggles, gloves, and ear protection
  • Measuring tape and marker
  • Utility knife
  • Caulking gun and high-quality, self-leveling sealant
  • Dry cloth (for cleaning)
  • Ladder or scaffolding (for roof access)
  • Multimeter (for electrical checks)
  • Ratchet straps or extra hands (to lift the unit safely)

Prerequisites

  • Clear workspace: Remove all items from the roof and interior ceiling area where you’ll be working.
  • Power off: Disconnect the campervan battery and any shore power to ensure safety while working with electrical components[2].
  • Check underneath: Identify any obstructions (wiring, support beams, etc.) before cutting the roof.
  • Review manual: Read the unit’s installation manual thoroughly—setup can vary by brand and model[1].
  • Gather materials: Ensure you have all mounting hardware, gaskets, and sealants provided with the AC unit.

Step-by-Step Instructions

  1. Mark and cut the roof opening: Use the interior faceplate as a template to mark a 14" x 14" hole. Double-check for obstructions, then carefully cut the opening using a jigsaw or angle grinder. Clean all metal shavings and apply rust prevention spray to the exposed edges[1].
  2. Prepare the sealing surface: Clean the roof area around the hole with a dry cloth to ensure proper adhesion of the gasket and sealant[1].
  3. Install the gasket and sealant: Place the rubber gasket around the hole. Apply a generous bead of self-leveling sealant on both the gasket and the roof for a watertight seal.
  4. Lift and position the AC unit: With help (preferably 2–3 people), carefully lift the AC unit onto the roof. Slide it into the opening, ensuring it sits level. Use foam blocks or brackets as needed to support and level the unit without stressing the roof panel[1][3].
  5. Secure the unit: From inside the van, install any provided mounting brackets or reinforcing panels to distribute the load. Tighten all bolts evenly to avoid warping the roof[3].
  6. Wire the AC: Route the power cables through a sealed entry gland. Connect to your 12V system using appropriately sized cables and fuses. Double-check all connections with a multimeter before restoring power[3].
  7. Reassemble interior components: Attach the interior vent, faceplate, and any air directors or insulation as specified by your unit’s manual.
  8. Test the system: Restore power and test the AC unit for proper operation. Check for leaks (water and air) and listen for unusual noises.

Common Mistakes

  • Cutting without checking for obstructions: Always confirm there’s clear space below the cut area to avoid damaging wiring or supports[1].
  • Poor sealing: Skimping on sealant or misaligning the gasket can lead to leaks and water damage.
  • Over-tightening mounting bolts: This can warp the roof or crack the gasket.
  • Undersized wiring: Using cables that are too thin can cause overheating and reduce efficiency.
  • Skipping the manual: Installation details vary by model; always follow the manufacturer’s instructions[1].

Pro Tips

  • Use a moving blanket: Protect the roof and unit during installation to prevent scratches.
  • Level carefully: Use a spirit level to ensure the unit sits flat—this avoids strain and potential leaks.
  • Seal all penetrations: Beyond the gasket, seal any screw holes or cable entries with additional sealant[1].
  • Insulate the air path: Use foam tape to seal gaps between the unit and roof to prevent “short cycling” of air[3].
  • Document your work: Take photos during installation for future reference or troubleshooting.

Time Estimate

  • Basic installation: 4–6 hours for a first-timer, assuming all tools and materials are on hand.
  • Experienced installer: 2–4 hours, depending on roof access and electrical routing complexity.

Installation time can vary based on your experience, the complexity of your van’s roof structure, and the specific AC model. Always prioritize safety and take your time to ensure a durable, leak-free install[1][3].

Frequently Asked Questions

Installing a rooftop AC unit requires moderate installation skills and careful planning. The process involves several key steps: turning off all power sources, marking and cutting a rectangular opening in your van's roof (typically 14 inches for standard installations), cleaning the roof surface thoroughly, applying gasket sealant, mounting the unit with proper leveling, and wiring it to your battery system. You'll need 2-3 people to safely lift the unit onto the roof, as these units are heavy and awkward to maneuver. The installation also requires precision work like trimming styrofoam deflectors, sealing gaps with insulation foam, and ensuring proper electrical connections. While it's a manageable DIY project for those with basic construction and electrical knowledge, it does involve permanently cutting into your van's roof, so careful measurement and execution are critical to avoid leaks.

Yes, rooftop AC units are generally compatible with all major camper van models including Mercedes Sprinter, Ford Transit, and RAM ProMaster. The key consideration is the roof opening size and available roof space. Most 12V rooftop units are designed to fit standard 14-inch roof openings, making them adaptable across different van platforms. However, you should verify your specific van's roof construction, headroom clearance inside the van, and whether your roof can support the weight of the unit (typically 40-60 pounds). The compact, low-profile design of modern 12V units makes them suitable for most van conversions. Location on the roof is flexible—you can install them toward the front or rear depending on your interior layout and where you want the cooling directed.

12V rooftop AC units typically draw between 32-33 amps during operation, which is substantial and requires a robust battery setup. For a 10,000 BTU unit running at full capacity, you're looking at approximately 400 watts of power draw. To run these units effectively, you'll need a proper lithium battery bank (at least 300-400 amp-hours recommended for extended use), a quality solar charging system, and heavy-duty gauge power cables for the connection. The advantage of 12V DC units is they run directly off your battery without needing an inverter, making them more efficient than traditional 115V AC units. However, expect your batteries to deplete relatively quickly without adequate solar charging or shore power to replenish them. Many van lifers find they can run their AC for 2-4 hours on battery alone before needing to recharge.

BTU (British Thermal Unit) capacity should match your van's interior volume and insulation quality. As a general guide, small vans require 4,000 to 7,000 BTU, while larger motorhomes need more. Most standard camper van conversions (Sprinter, Transit, ProMaster) work well with 10,000 BTU units, which can cool the interior from over 90°F to around 64°F within minutes. Consider these factors when sizing: your van's insulation quality (better insulation requires less BTU), ceiling height, number of windows, typical climate conditions where you'll travel, and whether you'll run the AC while driving or only when parked. Oversizing slightly is better than undersizing—a 10,000 BTU unit can always run at lower settings, but an undersized unit will struggle in extreme heat and run constantly, draining batteries faster.

Regular maintenance for rooftop AC units is relatively straightforward but essential for longevity. Key maintenance tasks include: cleaning or replacing air filters monthly during heavy use, inspecting the roof gasket and sealant annually for cracks or deterioration, cleaning the exterior condenser fins to remove debris and ensure proper airflow, checking electrical connections for corrosion, and draining any condensation that accumulates. The remote control batteries should be replaced as needed. With proper maintenance and care, quality 12V rooftop units can last 5-10 years or more. The main factors affecting longevity are exposure to extreme weather, frequency of use, quality of installation (proper sealing prevents water damage), and whether the unit is protected during off-season storage. Regular inspections of the roof seal are particularly important, as water intrusion is the primary cause of premature failure in rooftop installations.

Common issues include: inadequate cooling (often caused by dirty filters, blocked vents, or air short-circuiting between intake and output), excessive battery drain (check for proper voltage, battery capacity, and solar charging capability), water leaks around the unit (inspect gasket seal and roof sealant, reapply as needed), unusual noises (may indicate loose mounting bolts or debris in the fan), and unit not powering on (verify electrical connections, check fuses, ensure proper polarity on DC connections). Air short-circuiting is a frequent problem where cool air is immediately pulled back into the intake without circulating through the van—this is prevented by properly installing the styrofoam deflector and sealing gaps between the unit and ceiling. If cooling performance drops suddenly, check that the exterior shroud isn't blocked by debris and that all interior vents are properly directing airflow. Most issues can be resolved with basic troubleshooting, but severe electrical or mechanical problems may require professional service or warranty support.

Before installation, ensure you have the necessary tools and materials: jigsaw or reciprocating saw for cutting the roof opening, drill with appropriate bits, measuring tape and level, sealant (butyl tape or specialized RV sealant), insulation foam, mounting hardware (usually included), heavy-gauge power cables rated for 30+ amps, and scaffolding or sturdy ladders. Preparation steps include: disconnecting all power sources (battery, shore power, generators), thoroughly cleaning the roof area where the unit will mount, accurately measuring and marking the 14-inch opening location (accounting for interior ceiling clearance and roof structure), verifying your electrical system can handle the amperage draw, and planning wire routing from the roof to your battery bank. You'll also need to prepare the interior ceiling—some installations require framing around the opening for proper support of the interior panel. Having 2-3 people available for the actual mounting is essential for safety and proper positioning.

Most reputable 12V rooftop AC manufacturers offer warranties, though terms vary by brand. Typical warranty coverage ranges from 1-3 years for parts and labor, with some manufacturers offering extended warranties for purchase. When selecting a unit, look for companies that provide accessible customer support, detailed installation manuals, and online resources including video guides. Many brands offer remote-controlled operation with digital displays and thermostats for ease of use. Check whether the manufacturer provides technical support for installation questions and troubleshooting. Some companies also offer promotional discount codes (for example, some manufacturers provide $30 off with specific coupon codes). Be sure to register your product after installation to activate the warranty. Keep all documentation including purchase receipts, installation photos, and maintenance records, as these may be required for warranty claims. Quality manufacturers stand behind their products and will help resolve issues that arise during normal use.
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