Buying guide · 10 min read · Updated October 2, 2026

6 Best Soft Start For 13500 Btu RV AC in 2026: A Practical RV Guide

Soft starts for 13,500 BTU RV air conditioners, plus a built-in-soft-start Coleman-Mach unit, compared on BTU coverage, generator fit and price.

By Bowen HigginsRV Editor at RV Gear Lab6 products comparedSpec-sheet researched

A 13,500 BTU rooftop air conditioner is the most common RV size, and most soft starts are rated well above it. The decision is less about whether a kit fits and more about generator size, install effort and whether you want to replace the AC instead.

The shortlist includes five add-on kits and one Coleman-Mach Mach 10 unit with soft start built in. Prices run from about 52 to over 1,100 dollars.

RV Gear Lab field notes

The Rig Fit Check

Start with the job: SoftStartRV Soft Start for RV Air Conditioner leads this shortlist for RV roof fit. Use that fit as a reference point, then compare the alternatives against your own space and workload.
Specs that separate the picks: The first details to compare are 40% smaller, fits low-profile, Up to 20,000 BTU, 120V, 65 to 70% startup cut. Confirm the exact model and included components before ordering.
Trade-off to plan for: Wiring work still required

Before you buy

What Matters Before You Choose a Soft Start For 13500 Btu RV AC

Key buying criteria so you get the right fit the first time.

01
Match the kit to 13,500 BTU
A 13,500 BTU AC is about 1.1 tons, so most soft starts rated to 3 tons or more have plenty of margin. A kit that only names 15,000 BTU still covers it. Look for a stated BTU or tonnage range on the listing.
02
Generator size
A 2200W inverter generator can run a 13.5k AC with a soft start, but only if little else is running. Check the generator wattage the listing quotes. Plan for lights and the fridge on top.
03
Add-on kit vs replace
A kit costs 50 to 355 dollars, while a new Mach 10 unit costs over 1,100. Replace only if the AC is old or failing. Otherwise the kit is far cheaper.
04
Waterproof and low-profile fit
A rooftop shroud has little space and gets wet. A 100 percent waterproof or small unit is easier to place. Check the stated size and weather rating.
05
Capacitors and contactors
Some kits include start and run capacitors inside, so no extra part is needed. Others may need extra components. Read the box contents on the listing.

Our standards

Why You Can Trust RV Gear Lab

At RV Gear Lab, we compare products based on rig fit and power or hookup compatibility, verified specifications, usability, setup requirements, weight, durability, and real-world trade-offs. We do not rank products purely on marketing claims or commission rates.

We have not personally tested every product listed. Where hands-on testing is not available, recommendations are based on verified manufacturer specifications, product documentation, use-case fit, and comparative research.

How we review RV gear →

Detailed reviews

The 6 best soft start for 13500 btu rv ac, explained

Best Overall · 1 of 6

SoftStartRV Soft Start for RV Air Conditioner

40% smaller, fits low-profile
100% waterproof
Starts two A/Cs on 30 amp

Check price on Amazon

Best for: RV roof fit

Our take

Its listing says it starts two A/Cs on 30-amp, one on a small generator or 15-amp, and runs a 15,000 BTU A/C on a 2200W generator.

Why it made the shortlist

It costs about 60 dollars less than the SoftStart Home and is built for RV rooftops rather than home systems. It also starts two A/Cs on 30 amp.

It suits RV owners who want an RV-fit kit with a strong waterproof rating.

What works

Fits low-profile RV air conditioners
100% waterproof
Starts two ACs on 30 amp
Quieter compressor startup

Watch out for

Wiring work still required

The catch: The SoftStartRV unit is 40 percent smaller to fit low-profile RV A/C units, waterproof and listed to run a 15,000 BTU A/C on a 2200W generator.

Check price on Amazon

Best Coverage · 2 of 6

Spartan Power SpartanStart

Up to 20,000 BTU, 120V
Generator Anti-Stall and Preload
Splice connectors included

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Best for: Headroom up to 20,000 BTU

Our take

A Generator Anti-Stall and Preload feature tempers compressor startup, and the kit includes splice connectors, a cleaning wipe and mounting tape.

Why it made the shortlist

The Spartan Power SpartanStart is listed for RV air conditioners up to 20,000 BTU on a 120V circuit, started from a 2200 watt inverter or generator. The Spartan Power SpartanStart is listed for RV air conditioners up to 20,000 BTU on a 120V circuit, started from a 2200 watt inverter or generator.

It leaves more headroom above 13,500 BTU than the SEEMINE and BELZAR and adds a generator anti-stall feature. It costs about 105 dollars less than the SoftStartRV.

It suits owners who may upgrade to a larger AC later.

What works

Generator anti-stall feature
Covers up to 20,000 BTU
Install accessories included
Switches between generator and shore

Watch out for

Fewer waterproof details listed

Check price on Amazon

Best Budget Capable · 3 of 6

RV AC Soft Start Kit for 1.75-3.5 Ton Air Conditioners

65 to 70% startup cut
Up to 3 ton (36,000 BTU)
Capacitors preinstalled

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Best for: Preinstalled capacitors

Our take

Start and run capacitors are preinstalled inside, so no external contactor is required.

Why it made the shortlist

The SEEMINE kit cuts startup amps by 65 to 70 percent and handles rooftop RV ACs up to 3 tons, with capacitors preinstalled. The SEEMINE kit cuts startup amps by 65 to 70 percent and works with 115 to 240V, 50 or 60Hz rooftop RV ACs up to 3 tons (36,000 BTU).

It costs about 23 dollars more than the BELZAR and adds a stated tonnage range. No external contactor is required.

What works

Capacitors preinstalled inside
115 to 240V, 50 or 60Hz
Covers up to 36,000 BTU

Watch out for

Lesser-known brand
Thin warranty detail

The catch: It suits budget buyers who want a stated capacity and fewer parts.

Check price on Amazon

Best Budget · 4 of 6

BELZAR Soft Start for RV Air Conditioner

65 to 70% startup cut
15,000 BTU on 2200W generator
Flame-retardant ABS enclosure

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Best for: Buyers comparing capacity, compatibility, included components and storage needs

Our take

It uses a flame-retardant, dust-proof ABS enclosure with built-in over-voltage, over-current and short-circuit protection.

Why it made the shortlist

BELZAR undercuts the rest of this lineup on price while powering a 15,000 BTU AC from a 2200W generator. Starting current falls by 65 to 70 percent, so a 13,500 BTU unit gets an even easier start than the rating it is listed for.

It has overload protection and a flame-retardant enclosure, and undercuts every other add-on kit.

It suits owners who want the cheapest working kit.

What works

Built-in overload protection
Flame-retardant ABS enclosure
Works on 2200W generator

Watch out for

Lesser-known brand
Little install detail

Check price on Amazon

Best Large Range · 5 of 6

SoftStart Home

Up to 70% startup reduction
Up to 6 tons, 110 to 240V
15-minute DIY install kit

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Best for: Up to 6 tons, 110 to 240V

Our take

It runs on generators, RVs and solar, and ships with crimp connectors, zip ties, adhesive backing and a 15-minute DIY install guide.

Why it made the shortlist

The SoftStart Home from NetworkRV reduces startup power by up to 70 percent and covers units up to 6 tons on 110 to 240V. The SoftStart Home from NetworkRV reduces startup power by up to 70 percent and covers units up to 6 tons (72,000 BTU) on 110 to 240V.

It includes a full install kit and is a home-and-RV model, so it covers far more than 13,500 BTU.

It suits owners with several units or a home plus RV use.

What works

Up to 6 ton coverage
Complete install kit
Works with generators and solar
Reduces compressor stress

Watch out for

Home model, not RV-specific

Check price on Amazon

Best Replace Option · 6 of 6

Coleman-Mach 45203-0753 Mach 10 Soft Start Series Low-Profile Air Conditioner

13,500 BTU/h non-ducted
Low-profile design
Built-in quiet start

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Best for: Replacing the AC outright

Our take

It replaces the whole rooftop unit instead of adding a kit, so the soft start is built into the AC.

Why it made the shortlist

The Coleman-Mach Mach 10 Soft Start Series is a 13,500 BTU/h low-profile, non-ducted air conditioner with a quiet-start design. The Coleman-Mach Mach 10 Soft Start Series is a 13,500 BTU/h low-profile, non-ducted air conditioner with a quiet-start design.

It replaces the whole rooftop unit instead of adding a kit, so no extra wiring is needed. It costs far more than any add-on.

It suits owners already replacing a failed 13,500 BTU AC.

What works

Soft start built into the AC
Low-profile non-ducted design
13,500 BTU/h cooling capacity
No add-on wiring needed

Watch out for

Replaces the whole AC

Check price on Amazon

Methodology

How We Built This Shortlist

Each pick was assessed across 5 criteria weighted for real-world use.

BTU coverage

Rated BTU and tonnage coverage was compared against the 13,500 BTU target.

Generator fit

Stated generator sizes and breaker limits were compared.

Install effort

Wiring, harnesses and kit contents were compared.

Protection

Waterproofing and electrical protection were compared.

Price

Prices from 52 to 1,140 dollars were compared.

Decision guide

Match a Soft Start For 13500 Btu RV AC to Your RV

By Install Style

Your situation	Recommended pick	Why
RV roof, compact fit	SoftStartRV Low-Profile	40% smaller, waterproof.
Future bigger AC	Spartan SpartanStart	Up to 20,000 BTU.
Budget with stated range	SEEMINE Soft Start	Up to 3 tons, capacitors inside.
Lowest cost	BELZAR Soft Start	Lowest price.
Replace the AC	Coleman Mach 10	Soft start built in.

By Budget

Budget	Recommended pick
$50 to $80	BELZAR Soft Start or SEEMINE Soft Start
$180 to $300	Spartan SpartanStart or SoftStartRV Low-Profile
$350 to $1150	SoftStart Home or Coleman Mach 10

Add-On Kit vs Replacement AC

Add-on kit

Keeps your existing AC and costs far less, as with the SoftStartRV Low-Profile, Spartan SpartanStart, SEEMINE Soft Start and BELZAR Soft Start.

Replacement AC

Builds in a quiet start and removes wiring, as with the Coleman Mach 10.

Most buyers should pick the SoftStartRV Low-Profile and replace the AC only when it fails.

By Budget

Budget	Recommended pick
Under 60 dollars	BELZAR Soft Start
60 to 100 dollars	SEEMINE Soft Start
100 to 250 dollars	Spartan SpartanStart
Above 250 dollars	SoftStartRV Low-Profile

For a 2200W Generator Specifically

Look for

A stated 2200W generator capability and 13,500 or 15,000 BTU coverage.

In this comparison

The BELZAR Soft Start and SoftStartRV Low-Profile both list a 15,000 BTU AC on a 2200W generator.

When to Spend More

Spend more if

Spend more on the SoftStartRV Low-Profile or Coleman Mach 10 for RV fit or a built-in start.

Save if

Save with the BELZAR Soft Start or SEEMINE Soft Start.

FAQ

Before You Bring One Home

Will a soft start work on a 13,500 BTU AC?

Yes. Most kits list 15,000 BTU or 3 tons, which covers 13,500 BTU. Check the stated range.

What mistake do buyers make?

They buy a kit with no stated capacity. Choose one that names a BTU or tonnage range.

Is the Coleman Mach 10 worth the cost?

Only if you are replacing the AC anyway. Otherwise a kit is far cheaper.

How do I install a kit?

Turn off power, follow the wiring diagram and secure the unit in the shroud. Test with only the AC running.

Can I use one kit on two ACs?

The SoftStartRV Low-Profile lists two A/Cs on 30 amp. Most other kits need one per AC.

Bottom line

The short version

Browse more soft start for 13500 btu rv ac on Amazon →

About the author

Bowen Higgins

RV Editor at RV Gear Lab

Bowen covers RV power, water systems, towing and leveling, upkeep and interior comfort, with a focus on matching gear to the rig, the hookups and the way you actually travel.

6 Best Soft Start For 13500 Btu RV AC in 2026: A Practical RV Guide

Our top picks

The Rig Fit Check

What Matters Before You Choose a Soft Start For 13500 Btu RV AC

Match the kit to 13,500 BTU

Generator size

Add-on kit vs replace

Waterproof and low-profile fit

Capacitors and contactors

Why You Can Trust RV Gear Lab

The 6 best soft start for 13500 btu rv ac, explained

SoftStartRV Soft Start for RV Air Conditioner

Spartan Power SpartanStart

RV AC Soft Start Kit for 1.75-3.5 Ton Air Conditioners

BELZAR Soft Start for RV Air Conditioner

SoftStart Home

Coleman-Mach 45203-0753 Mach 10 Soft Start Series Low-Profile Air Conditioner

How We Built This Shortlist

BTU coverage

Generator fit

Install effort

Protection

Price

Match a Soft Start For 13500 Btu RV AC to Your RV

By Install Style

By Budget

Add-On Kit vs Replacement AC

By Budget

For a 2200W Generator Specifically

When to Spend More

Before You Bring One Home

Will a soft start work on a 13,500 BTU AC?

What mistake do buyers make?

Is the Coleman Mach 10 worth the cost?

How do I install a kit?

Can I use one kit on two ACs?

The short version

Bowen Higgins

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