Generac and Kohler both provide outstanding home standby generators. Their most popular models are the 20kW – 22kW home standbys. Although these units are similar, there are some differences that set them apart. We know that while you are initially shopping for generators, it can be hard to look passed the price alone, so, we have decided to break down some of the less obvious differences in the two brands.

Enclosure

With the exception of the discontinued model 5837 generator all other Generac air cooled home standby and liquid cooled generators will have a metal enclosure, either steel or aluminum. Since both of these enclosures are nonflammable you can have them as close as eighteen inches from a noncombustible surface, however, they need to be three feet from a combustible surface. Keep in mind that even with these clearances your local ordinance will have the final say. If you are anywhere near salt water it is important to avoid a steel enclosure because that will accelerate the rate at which the enclosure will rust.

When it comes to enclosures Kohler is going to differ quite a bit from Generac. There are three different types of enclosures that are offer which would be the composite plastic, steel, and aluminum. The standard residential home standby units will be made of the composite plastic material. Since plastic burns and doesn’t have a fire rating you’ll have to have it further from the home. The advantage, however, is that plastic isn’t corrosive. You can place a generator with this enclosure in a salt water area without worry. Clearances for this type of enclosure are going to be two feet from a noncombustible surface and five feet away from anything combustible. As stated before that can differ depending on your local ordinances since they have the final say. The  20kW RESA model also has the option of being offered in aluminum if needed, however it’s special order and will be a little more expensive. For the steel and aluminum enclosures, standard on the liquid-cooled models, the clearances are still eighteen inches from noncombustible surfaces and three feet away from combustible surfaces.

As for sound ratings the Kohler units with composite plastic and the residential models that offer steel or aluminum will be about the same decibel rating as the Generac residential models. They might differ by a decibel or two, but nothing so significant that it is unbearable.

Controller

The current controller for Generac, at the time this article was written, would be the Evolution controller. While the Nexus controller was a very effective component in the Generac generator system, the Evolution does a great job of improving on it. Out of all of the changes what is extremely noteworthy would be the addition of the usb port on the control board. A small change we know, but that small change comes with a huge advantage. With the older version controller if there was an issue that required an update the entire board might have to be replaced or adjustments would be required. On the Evolution control board because of the usb port updating is very simple. All you’ll need to do is download the update to an usb device and then connect it to the board. Even with the ease of it we still recommend that you have an authorized Generac technician handle all of the updates for the unit.

Kohler has two different control boards that they use currently, labeled as the RDC2 and the DC2 control boards. The DC2 controller is a very basic 4-wire start system. It allows for the unit to be connected to a Kohler transfer switch and automatically control power loss/gain to the home. Since it doesn’t have the same intelligence there is also a laptop that will be required to install this type of controller. The RDC2 controller is a bit different than the DC2.  RDC2 controllers have a 6 button interface and the technician can perform additional settings to the generator without the need for our technical software. The RDC2 controllers are on all RESV, RESA, RESB and RCL generators. It can also be connected to an inverter for off-grid use with a battery back-up system. On top of it all you still have the option to use a Kohler 4-wire transfer switch if you prefer to do that. 

DC2 controllers are standard on the "L" model RESAL and RESVL models which are bundled with automatic transfer switches. The DC2 controllers have a 4 button interface. Because these are sold almost exclusively through the Retail/E-Tail channels, and there is no guarantee the unit will be installed by a trained professional, so the technical software is necessary for many of the setting adjustments that should not be performed by an untrained installer. The controllers operate almost exactly the same.

Also,all generators with these controllers are compatible with the RXT and RDT transfer switches. The RXT models require the RDC2 or DC2 controllers, because the generator controller tells the ATS when to engage. The RDT transfer switches are a simple 2 wire system that tells the generator when to engage.

Both brands offer outstanding reliability and quality craftsmanship. If you want to know more about the differences in specific generator models feel free to reach out to us by phone or via live chat today.