10 Best RV Air Conditioner Soft Starts for Easier Starts

A soft start for an RV air conditioner is a small box that ramps the compressor up slowly instead of letting it slam on at full power. That’s the whole idea. What changes between these picks is how they install, what they fit, and how much power they save you on startup.

Best overall: SoftStartRV Soft Start – it’s 100% waterproof, fits low-profile rooftop units, and the listing says it can start two A/Cs on 30-amp power.

Best for Coleman-Mach units: Coleman-Mach Soft Start Kit – built for Series 45000, 47000 and 48000 air conditioners, installs from outside your coach, and carries a 2-year limited warranty.

Easiest no-install setup: SoftStartUp Plug & Play – no tools, no rooftop access, no wiring. You plug it into your power source and connect your RV.

The rest of this guide walks through all ten picks, then answers the questions buyers ask before ordering.

How We Picked

We compared the Amazon listings for RV air conditioner soft starts. To earn a place here, a listing had to state real facts: what the unit fits, how much it cuts startup power, what’s in the box, and what the seller covers afterward. Vague listings that only promised “smoother starts” without numbers or fitment details didn’t make it.

Installation also matters. Some soft starts need you on the roof with a wiring diagram. Others plug in at the pedestal. Both are valid, but the listing has to say which one it is, and a lot of them don’t.

Warranty and support mattered too. A soft start sits on your A/C compressor in heat, rain, and road vibration, so what the seller covers when it fails is part of the product, not a footnote. Listings with a stated warranty and a stated support path ranked higher than ones that stayed quiet on both.

All 10 products side by side — scroll sideways to see every column.

1. SoftStartRV Soft Start

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Best for: RV owners who want one unit to do everything

This is the pick that tries to cover the most ground. The listing says it’s now 40% smaller, so it fits low-profile RV A/C units where space is tight. It’s also stated as 100% waterproof, which matters on a roof that sees rain, road spray, and hose-downs.

The power claims are the headline. According to the listing, it starts two A/Cs on 30-amp service, one A/C on a small generator, or one on 15-amp. It’s rated to work with a 2200W generator and to power up to 36,000 BTUs, including a 15,000 BTU rooftop unit. That’s the difference between running your A/C on limited power and not running it at all.

Setup is where it earns its keep for a first-timer. The listing offers guides, tutorials, and live support, with free help from certified technicians. It also claims reduced compressor noise and vibration. What the listing doesn’t state is a warranty length – it states a 30-day satisfaction guarantee instead. So if long-term coverage is what you’re after, that’s the trade-off. This isn’t for someone who wants zero wiring work at all; that buyer should look at the plug-and-play pick below.

Pros

• Fits low-profile units after 40% size reduction
• 100% waterproof for rooftop mounting
• Free support from certified technicians

Cons

• Listing states a satisfaction guarantee, not a warranty term

2. MICRO-AIR EasyStart Flex 398 Soft Start Kit

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Best for: Homeowners and RVers who want a documented install

Micro-Air’s Flex 398 is the kit that reads like it was written by installers. The listing states it lowers locked-rotor inrush current by up to 75%, which is the number that stops breakers from tripping when the compressor kicks in.

The install is the selling point. It’s a 4-wire hookup with color-coded wiring, and the listing includes step-by-step video guides. If you’ve ever stared at a wiring diagram on a hot roof, that’s worth something. It also adds Bluetooth app diagnostics and built-in fault system protection, so when something goes wrong you’re reading a fault code instead of guessing.

Compatibility is broad: single-stage, two-stage, and heat pump systems rated from 2 to 6 tons. That range is why this one shows up on home A/C setups as often as RV ones. The trade-off is that broad fitment comes with a bigger job – this isn’t a plug-in device, and it isn’t aimed at someone who wants to avoid tools.

Pros

• Cuts locked-rotor inrush current up to 75%
• 4-wire color-coded hookup with video guides
• Bluetooth app diagnostics and fault protection

Cons

• Requires a real wiring install, not a plug-in

3. Coleman-Mach Soft Start Kit

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Best for: Owners of a Coleman-Mach rooftop unit

If your RV already has a Coleman-Mach air conditioner, this is the one built for it. The listing states it fits Series 45000, 47000 and 48000 units specifically, which removes the guesswork that comes with universal kits.

It reduces inrush amperage up to 75% and lessens overall power consumption. The listing explains the mechanism plainly: it creates a ramped-up power draw at cycle startup so voltage climbs smoothly instead of spiking. There’s also short-cycle protection, which the listing states lowers startup stress on the compressor.

Two things stand out for real use. First, the unibody enclosure is stated to protect the unit across a range of weather conditions. Second, it installs from the exterior of your coach – no interior work, and no change to how the A/C looks from outside. It carries a 2-year limited warranty, and the listing says installation won’t adversely impact your existing Coleman-Mach warranty. That last point is the one to check if your rig is still under coverage. This isn’t for you if you don’t own a Coleman-Mach unit – the fitment list is narrow on purpose.

Pros

• Fits Coleman-Mach Series 45000, 47000, 48000
• Limited warranty included, existing warranty unaffected
• Installs from outside the coach

Cons

• Only fits the listed Coleman-Mach series

4. MICRO-AIR EasyStart Breeze 399 Bluetooth Soft Start

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Best for: Off-grid campers who want Bluetooth monitoring

The Breeze 399 is the RV-focused sibling of the Flex, and it’s aimed squarely at boondockers. The listing says it runs your camper A/C off a single 2200W inverter generator, which means less fuel, less noise, and no hauling a second generator.

Installation is stated as a quick job, with a 40-inch harness and color-coded wiring, plus step-by-step guides and video support. That’s a short job. Compatibility covers most RV rooftop models up to 18,000 BTU, and the enclosure is described as compact enough to fit tight spaces.

The part that separates it from the Flex is the brain. A built-in micro-controller watches for overcurrent, stall conditions, and low voltage drops, and it reports real-time fault diagnostics over Bluetooth. The 4-part ramp-up process cuts locked-rotor amperage by up to 75%, same as its sibling. The ceiling here is the 18,000 BTU fitment – if you’re running a bigger rooftop unit, this isn’t the one. The listing also doesn’t state a warranty term.

Pros

• Bluetooth monitoring with real-time fault diagnostics
• Stated quick install with 40-inch harness
• Fits most RV rooftop units up to 18,000 BTU

Cons

• 18,000 BTU fitment ceiling
• Listing states no warranty length

5. Spartan Power SpartanStart

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Best for: Big rooftop A/Cs up to 20,000 BTU

Most soft starts top out at 15,000 or 18,000 BTU. The SpartanStart is listed for up to 20,000 BTU, which is the highest ceiling in this group. It’s stated to start that load with a 2200 watt power inverter or generator without draining your battery.

Two features are unusual here. The generator anti-stall and preload feature is described as pre-empting generator duress before compressor startup, and it switches between generator, inverter, or campsite power with no learning cycles. There’s also motor reversal protection during short power outages, which is the kind of thing that quietly saves a compressor.

Installation is three wires. You find the R (Run), C (Common), and S (Start) wires on your compressor, match them to the labeled wires on the SpartanStart, and you’re done. The box includes 6 splice connectors, a cleaning wipe, and 2 automotive-grade mounting tape strips. It’s made in Australia with US support, and it carries the longest stated warranty term in this group. The listing asks that you call with install questions before returning, so support runs through the seller directly.

Pros

• Handles up to 20,000 BTU, the highest here
• 3-year warranty, longest stated term
• Three-wire install with connectors included

Cons

• Support runs through a phone call, not an app

6. SoftStartUp Plug & Play

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Best for: Renters and anyone avoiding tools entirely

This is the one that skips the install. You plug SoftStartUp into your power source, connect your RV, and the A/C starts smoothly from campground power or a generator. No tools, no wiring, no rooftop access, no installer.

It’s built for travel trailers, Class B, and Class C RVs, and it works with common campsite hookups plus small generators down to 2200 watts. The listing states it reduces startup inrush current by up to 50% – lower than the 75% the hardwired kits claim, and that’s the honest trade for skipping the install. Built-in overload protection is stated to reduce mechanical stress during startup.

The design is weatherproof and portable, so you can move it between RVs or campsites, and a power adapter is included. There’s one hard limit you need to read before ordering: the listing states it doesn’t work with an Auto Transfer Switch. If your RV has an ATS, this pick is out. For everyone else, it’s the lowest-effort way onto this list.

Pros

• No installation, wiring, or rooftop access
• Works with 30A/50A and 2200W generators
• Weatherproof, portable, power adapter included

Cons

• Stated 50% inrush reduction, less than hardwired kits
• Doesn’t work with an Auto Transfer Switch

7. TURBRO RV AC Soft Start Kit

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Best for: Non-inverter A/Cs on tight campsite hookups

TURBRO’s kit is aimed at a specific problem: non-inverter RV A/Cs that pull over 40A at startup. The listing states it cuts startup power by 60-75%, and it fits units up to 15,000 BTU.

The dual A/C claim is the one worth reading twice. According to the listing, two soft starters let you run two A/Cs with a total amperage under 30A on a 30A hookup. That’s a real change to how you use a campsite hookup. It also names generators it works with – Honda 2200, WEN 56203i, CAT INV2000, Westinghouse iGen2200 – which is more specific than most listings get.

Voltage range is 100-240V at 60 Hz, wider than the 115V models most kits use. Waterproofing is dual-layer: an outer shell plus an epoxy-sealed PCBA board, rated IPX5. Installation means disconnecting the compressor and control box harness and reconnecting through the soft starter. Read the reminder carefully – the listing says to remove original start components first, both PTCR and start capacitor, or the compressor can fail to start. This isn’t for you if you’d rather not touch existing start parts.

Pros

• Dual A/C operation on a single hookup with two starters
• 100-240V range, wider than 115V models
• Dual IPX5 waterproof protection

Cons

• Requires removing original start components first

8. Dometic SmartStart 120V Soft Start Accessory Kit

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Best for: Dometic FreshJet 3 owners who want factory parts

This is the factory option for a Dometic FreshJet 3 mechanical A/C. If your rig came with that unit, this is the kit designed to pair with it, and that’s worth more than any spec sheet.

The listing states it reduces A/C startup power demand by up to 75%. On 30-amp service, it allows two A/Cs when no other appliances are running, and it supports other appliances while one A/C runs. That second point is the practical one.

Build quality is stated for travel: a weatherproof case and connectors, vibration tested for severe road conditions. It’s pre-wired, so there’s no cutting or crimping, and the listing recommends professional installation. The listing also notes less compressor power draw can mean less noise at startup. Two limits: it’s specific to the FreshJet 3, and the listing states no warranty term. This isn’t for a universal fit.

Pros

• Designed for Dometic FreshJet 3 units
• Pre-wired, no cutting or crimping
• Weatherproof case, vibration tested

Cons

• Specific to FreshJet 3 mechanical A/C
• Professional installation recommended

9. TURBRO 15K BTU RV AC with Soft Start Kit

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Best for: Buyers replacing the whole rooftop unit

This is a different kind of pick: it’s a full 15,000 BTU rooftop air conditioner with the soft start kit included. If your old unit is done, you’re buying the A/C and the soft start in one box instead of two.

Cooling is 15,000 BTU, with 1,500W of electric heating plus fan and dry modes. The included soft starter cuts startup power by 60-75%, which is the same range TURBRO states for its standalone kit. Noise is listed at 52 dB, with a sleep mode for overnight. Controls include remote and app operation, an atmospheric LED lamp, and recessed handles for moving the unit.

Power compatibility covers 30A hookups and small generators with 100-240V support, and the soft starter is stated to enable dual A/C operation under 30A. Both the A/C and the starter are built for outdoor use, with a waterproof shell and epoxy-sealed circuit board on the starter. The trade-off is scope: this is a full replacement job, not an add-on. If your current A/C works fine, this isn’t the pick.

Pros

• 15,000 BTU cooling plus 1,500W heating
• Soft start kit included with the unit
• 52 dB operation with sleep mode

Cons

• Full A/C replacement, not an add-on part

10. TURBRO Finnmark 15K BTU RV AC with Soft Start Kit

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Best for: Four-season campers who want heat and cool

The Finnmark 15K is the second TURBRO all-in-one, and it carries the same core specs as the 15K above: 15,000 BTU cooling, 1,500W electric heating, fan and dry modes, and an included soft starter that cuts startup power by 60-75%.

What’s different is the framing. This one leans into year-round comfort and quiet – 52 dB operation, sleep mode, and a soft starter that’s stated to further reduce compressor noise and vibration. Controls are the same set: remote and app operation, atmospheric LED lamp, recessed handles. The soft starter uses a simple wiring setup with TEST/START/RUN indicators for troubleshooting, a genuinely useful detail if you like knowing what the box is doing.

Power side matches too: 30A hookups or small generators, 100-240V support, dual A/C operation under 30A, and surge protection. Both units are weather-resistant, with a waterproof shell and epoxy-sealed board on the starter. Like the 15K, this is a full replacement. It’s not for someone who only needs the soft start box.

Pros

• 15,000 BTU cooling and 1,500W heating
• TEST/START/RUN indicators on the starter
• 52 dB with sleep mode

Cons

• Full A/C replacement, not an add-on part

Also Worth Considering

SoftStart Home is built for home air conditioners and heat pumps rather than RVs. Its title states it reduces startup power by 70%, works with generators, RVs and solar, and covers units up to 6 tons (72,000 BTUs) with a stated 15-minute install. If you want one soft start that handles your house and your rig, that range is the reason to look.

SoftStartRV Conditioner Enables Your Start is a SoftStartRV soft starter for RV air conditioners, described in its title as letting your A/C start and run on a small generator. If you’re already leaning toward the SoftStartRV ecosystem, this is the same family of product under a different listing.

Soft Start RV Air Conditioners states it reduces startup current by up to 75%, with an easy DIY install, quiet start, IP65 waterproofing, and reverse motor protection. Its title lists home, RV, van and generator use, so it’s aiming at the same broad fitment as the Micro-Air Flex.

How to Choose in Sixty Seconds

Which soft start actually fits my RV air conditioner?

Check two things before anything else: your A/C’s BTU rating and its brand. If you own a Coleman-Mach Series 45000, 47000 or 48000, the Coleman-Mach Soft Start Kit is the direct fit. If you own a Dometic FreshJet 3, the Dometic SmartStart 120V is built for it. For everything else, match the BTU ceiling – the Micro-Air EasyStart Breeze 399 covers up to 18,000 BTU, and the Spartan Power SpartanStart goes to 20,000 BTU. The TURBRO kits fit up to 15,000 BTU.

Do I need a hardwired kit or the plug-and-play one?

It comes down to whether you’ll touch wiring. Hardwired kits cut startup current by up to 75% in most listings here, and they live permanently on the A/C. The SoftStartUp Plug & Play states up to 50% inrush reduction and needs no tools at all – you plug it in at the power source. So if you want the biggest reduction and don’t mind a wiring job, go hardwired. If you rent your RV, move between rigs, or simply won’t climb on the roof, the plug-and-play unit is the honest answer. One catch: the listing says it doesn’t work with an Auto Transfer Switch.

What should I confirm before I order?

Three things. First, whether your A/C is an inverter or non-inverter model – the TURBRO RV AC Soft Start is aimed at non-inverter units pulling over 40A at startup. Second, whether your unit has existing start components. The TURBRO listing states you must remove the PTCR and start capacitor, or the start relay and start capacitor, before installing, or the compressor can fail to start. Third, your power source. If you’re running a generator, check the listing’s stated wattage – 2200W comes up repeatedly here.

Does a soft start void my A/C warranty?

Not according to the listings here. The Coleman-Mach Soft Start Kit states directly that installation won’t adversely impact the existing Coleman-Mach warranty, and it carries its own 2-year limited warranty on top. The Spartan Power SpartanStart states a 3-year warranty. Others are quieter: the SoftStartRV Soft Start states a 30-day satisfaction guarantee rather than a warranty term, and the Micro-Air EasyStart Breeze 399 and Dometic SmartStart 120V don’t state a warranty length in their listings. If your A/C is still under its own coverage, confirm with that manufacturer before you install anything.

Related guides

• Coleman Mach Air Conditioner Manual: Ultimate Setup & Troubleshooting Guide
• Best Portable Air Compressor for Off Roading: Ultimate Cordless Air Compressor Review
• Coleman Mach Air Conditioner Troubleshooting: Quick Fixes Guide

Frequently Asked Questions

What does a soft start actually do to my A/C compressor?

It ramps the power up gradually instead of letting the compressor pull full locked-rotor current the instant it starts. The Coleman-Mach listing describes a ramped-up power draw at cycle startup for a smooth progression to running voltage, eliminating voltage spikes that trip breakers. Most kits here state they cut that inrush by up to 75%.

What goes wrong first with these units?

The TURBRO listing is explicit: if you leave the original PTCR and start capacitor, or the start relay and start capacitor, in place, those components will cause compressor startup failure. Waterproofing shows up in several listings here – 100% waterproof on the SoftStartRV Soft Start, IPX5 on the TURBRO, weatherproof cases on the Dometic and SoftStartUp.

Is the simplest one on the list enough for my setup?

If your goal is running one A/C on a small generator or weak campsite hookup, yes – the SoftStartUp Plug & Play covers that with no install and up to 50% inrush reduction. It’s enough for a travel trailer, Class B or Class C with a single rooftop unit. For dual A/C operation you need the hardwired route: the hardwired kits here state they can run two A/Cs on a single hookup, and the TURBRO kit states two units with two soft starters.

Conclusion

If you want the one that covers the most ground, the SoftStartRV Soft Start is the pick – waterproof, low-profile fitment, and stated to start two A/Cs on 30-amp power. If your rig has a Coleman-Mach unit, the Coleman-Mach Soft Start Kit is the direct fit and carries the 2-year limited warranty. Next step: find your A/C’s brand and BTU rating on the unit’s label, then match it to the pick above before you order.