Best RV Air Conditioner Soft Starters

A compressor's starting inrush can briefly demand roughly double its running wattage, which is the gap a soft starter closes. It does this with a component that limits the initial current spike as the compressor spins up, then steps out of the way once the motor is running normally. The running wattage draw afterward is unchanged, since a soft starter only touches the starting surge, not steady-state consumption. That is why a soft starter lets a generator sized for running watts alone finally start a unit it could power once running but never start from a stop.

We did not install or test these kits ourselves. These picks are built from each manufacturer's published BTU ratings and compatible generator sizes, along with verified owner reviews describing whether the kit actually let their generator or inverter start the air conditioner it was matched to. Where a brand did not state a maximum BTU rating, we did not assume one.

Check your air conditioner's BTU rating against the maximum each kit supports before choosing between them.

Not necessarily, but a soft starter is usually the cheaper fix for the same problem a bigger generator solves. If the only reason you are considering a larger generator is that the current one will not start the air conditioner, a soft starter costs less than the price difference between generator sizes in most cases and adds no weight to carry. If you need the extra running capacity for other loads too, such as two air conditioners at once, the bigger generator is the better answer. The soft starter versus bigger generator comparison walks through that decision in more detail.

Yes. A soft starter reduces starting inrush regardless of whether the power source is a generator, an inverter, or a shore power pedestal, which matters on a weak or overloaded 30 amp pedestal that struggles with the same starting surge a small generator does. It is not only a generator accessory, even though generator compatibility is the reason most owners buy one.

A wired soft starter kit installs a small component inside the air conditioner's own electrical housing, sealed against the same weather exposure the rest of a rooftop unit already handles, and once installed it has no separate enclosure of its own to fail. A plug and play unit lives outside the air conditioner as its own sealed module, which means one more weatherproof housing exposed to sun and rain on the roof, but it also means the air conditioner itself is never opened or modified, which some owners prefer for warranty reasons. Neither approach has a meaningfully different failure rate reported by owners; the choice mostly comes down to whether you would rather modify the air conditioner once or add a separate module next to it.

Opening a rooftop air conditioner to wire in a soft starter can be treated by some manufacturers as a modification that affects warranty coverage on the unit, so check your air conditioner's specific warranty terms before choosing a wired kit if the unit is still under warranty. A plug and play soft starter that installs outside the air conditioner's housing, without opening it, sidesteps that question entirely, which is one of the practical reasons some owners choose the higher-priced plug and play option over a cheaper wired kit even when both would solve the same starting problem.

Most single-unit rooftop air conditioners on travel trailers and fifth wheels fall into the 13,500 BTU class, with larger fifth wheels and some motorhomes stepping up to 15,000 BTU units, and larger coaches sometimes running two units of either size. All three soft starters on this page cover at least the 13,500 BTU class; only the SpartanStart publishes an explicit maximum BTU rating of 20,000, which also covers the 15,000 BTU size with room to spare. Check the BTU number stamped on your own unit's data plate rather than assuming a size based on the coach's overall length, since two similarly sized trailers can carry different BTU units depending on climate and manufacturer.

The kits on this page are built and rated for standard rooftop RV air conditioner compressors, the type mounted on the roof with a single sealed housing. A ductless mini-split or a window-style unit sometimes used in a larger coach uses a different compressor configuration, and compatibility should be confirmed against the soft starter manufacturer's own compatibility list before ordering rather than assumed from BTU rating alone.

All three cut compressor inrush current; they differ mainly in installation method and maximum BTU rating, so check your air conditioner's BTU size against each kit's rating before buying.