Buying Guide
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 Hardcastle's RV Editors
10 min read6 products evaluated
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.
Hardcastle’s RV field notes
The Rig Fit Check
A quick way to connect the shortlist to the space, workload and ownership details that matter after the box arrives.
- 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
The Practical Shortlist
A road-tested-thinking look at 6 options, organized around the job each one suits best.
Best Overall
SoftStartRV Soft Start for RV Air Conditioner
RV roof fit
Our take Check price for SoftStartRV Soft Start for RV Air Conditioner (opens in a new tab)
Best Coverage
Spartan Power SpartanStart
Headroom up to 20,000 BTU
Our take Check price for Spartan Power SpartanStart (opens in a new tab)
Best Budget Capable
RV AC Soft Start Kit for 1.75-3.5 Ton Air Conditioners
Preinstalled capacitors
Our take Check price for RV AC Soft Start Kit for 1.75-3.5 Ton Air Conditioners (opens in a new tab)
Best Budget
BELZAR Soft Start for RV Air Conditioner
buyers comparing capacity, compatibility, included components and storage needs
Our take Check price for BELZAR Soft Start for RV Air Conditioner (opens in a new tab)
Best Large Range
SoftStart Home
Up to 6 tons, 110 to 240V
Our take Check price for SoftStart Home (opens in a new tab)
Best Replace Option
Coleman-Mach 45203-0753 Mach 10 Soft Start Series Low-Profile Air Conditioner
Replacing the AC outright
Our take Check price for Coleman-Mach 45203-0753 Mach 10 Soft Start Series Low-Profile Air Conditioner (opens in a new tab)
Why Each Pick Made the Cut
Best Overall1 of 6
SoftStartRV Soft Start for RV Air Conditioner on Amazon (opens in a new tab)
SoftStartRV Soft Start for RV Air Conditioner makes the shortlist because fits low-profile RV air conditioners.
Best for
- RV roof fit
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.
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. It suits RV owners who want an RV-fit kit with a strong waterproof rating.
Key dimensions & specs
- 40% smaller, fits low-profile
- 100% waterproof
- Starts two A/Cs on 30 amp
Pros
- Fits low-profile RV air conditioners
- 100% waterproof
- Starts two ACs on 30 amp
- Quieter compressor startup
Cons
- Wiring work still required
Best Coverage2 of 6
Spartan Power SpartanStart on Amazon (opens in a new tab)
The strongest case for Spartan Power SpartanStart is generator anti-stall feature.
Best for
- Headroom up to 20,000 BTU
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.
A Generator Anti-Stall and Preload feature tempers compressor startup, and the kit includes splice connectors, a cleaning wipe and mounting tape. It suits owners who may upgrade to a larger AC later.
Key dimensions & specs
- Up to 20,000 BTU, 120V
- Generator Anti-Stall and Preload
- Splice connectors included
Pros
- Generator anti-stall feature
- Covers up to 20,000 BTU
- Install accessories included
- Switches between generator and shore
Cons
- Fewer waterproof details listed
Best Budget Capable3 of 6
RV AC Soft Start Kit for 1.75-3.5 Ton Air Conditioners on Amazon (opens in a new tab)
RV AC Soft Start Kit for 1.75-3.5 Ton Air Conditioners is the better fit when preinstalled capacitors.
Best for
- Preinstalled capacitors
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.
Start and run capacitors are preinstalled inside, so no external contactor is required.
Key dimensions & specs
- 65 to 70% startup cut
- Up to 3 ton (36,000 BTU)
- Capacitors preinstalled
Pros
- Capacitors preinstalled inside
- 115 to 240V, 50 or 60Hz
- Covers up to 36,000 BTU
Cons
- Lesser-known brand
- Thin warranty detail
Best Budget4 of 6
BELZAR Soft Start for RV Air Conditioner on Amazon (opens in a new tab)
Choose BELZAR Soft Start for RV Air Conditioner for built-in overload protection.
Best for
- buyers comparing capacity, compatibility, included components and storage needs
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 uses a flame-retardant, dust-proof ABS enclosure with built-in over-voltage, over-current and short-circuit protection. It suits owners who want the cheapest working kit.
Key dimensions & specs
- 65 to 70% startup cut
- 15,000 BTU on 2200W generator
- Flame-retardant ABS enclosure
Pros
- Built-in overload protection
- Flame-retardant ABS enclosure
- Works on 2200W generator
Cons
- Lesser-known brand
- Little install detail
Best Large Range5 of 6
SoftStart Home on Amazon (opens in a new tab)
SoftStart Home makes the shortlist because up to 6 ton coverage.
Best for
- Up to 6 tons, 110 to 240V
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 runs on generators, RVs and solar, and ships with crimp connectors, zip ties, adhesive backing and a 15-minute DIY install guide. It suits owners with several units or a home plus RV use.
Key dimensions & specs
- Up to 70% startup reduction
- Up to 6 tons, 110 to 240V
- 15-minute DIY install kit
Pros
- Up to 6 ton coverage
- Complete install kit
- Works with generators and solar
- Reduces compressor stress
Cons
- Home model, not RV-specific
Best Replace Option6 of 6
Coleman-Mach 45203-0753 Mach 10 Soft Start Series Low-Profile Air Conditioner on Amazon (opens in a new tab)
The strongest case for Coleman-Mach 45203-0753 Mach 10 Soft Start Series Low-Profile Air Conditioner is soft start built into the AC.
Best for
- Replacing the AC outright
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 replaces the whole rooftop unit instead of adding a kit, so the soft start is built into the AC. It suits owners already replacing a failed 13,500 BTU AC.
Key dimensions & specs
- 13,500 BTU/h non-ducted
- Low-profile design
- Built-in quiet start
Pros
- Soft start built into the AC
- Low-profile non-ducted design
- 13,500 BTU/h cooling capacity
- No add-on wiring needed
Cons
- Replaces the whole AC
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.
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.
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.
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.
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.
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.
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.
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. |
Scroll sideways to see every column.
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.
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
Best overall: SoftStartRV Soft Start for RV Air Conditioner — best overall pick in this roundup. See the full verdicts above for every pick, with pros, cons and who each one suits.
Browse all soft start for 13500 btu rv ac on Amazon — Prime-eligible options with current pricing.