# Generator Installation: Cost, Hours and Process in Hacienda Heights Generator installation fits a house generator into a coach that never had one, or replaces a unit at end of service. It is fabrication work as much as electrical work: a mount and enclosure, a fuel supply, an exhaust route, combustion air, and a transfer switch tied into the 120 volt panel. ## Specifications - Price band: $2,500 to $14,000 - Shop hours: 10 to 45 hours - Turnaround tier: Upfit and fabrication - Insurance billable: no - Parts lead time: Onan and Cummins units 10 to 30 business days. Mounts, exhaust and transfer switches 5 to 15 business days. - OEM brands: Onan, Cummins, Kohler, Generac, Progressive Dynamics ## Sizing, and the two questions that decide it The first question is how many air conditioners you intend to run at once, because they dominate the load. A single rooftop unit with a soft start plus normal coach loads fits inside a smaller generator. Two rooftop units plus a water heater element and a microwave needs meaningfully more. The second is fuel. A gas unit draws from the chassis fuel tank, which is simple on a motorhome and unavailable on most towables. A diesel unit does the same on a diesel coach. An LP unit is often the only practical answer on a fifth wheel or a travel trailer, and it comes with a specific caution covered below. We would rather fit the correct size than the largest available. An oversized generator running lightly loaded is harder on itself than a correctly sized unit running in its band, and it costs more to buy, more to mount and more to feed. - Number of air conditioners intended to run simultaneously - Fuel source available: gasoline, diesel or LP - Available bay volume, since enclosure and airflow clearance are not optional - Exhaust route that clears every window, vent and door opening - Combustion air path with adequate open area - Transfer switch and panel capacity on the 120 volt side ## Mount, exhaust and airflow are the parts that get done badly A generator is a vibrating, hot, exhaust producing engine bolted inside a wooden structure a few feet from where people sleep. Three details carry all of the risk: the mount, the exhaust route and the combustion air path. The mount has to isolate vibration and still hold the unit under road load. We fabricate to the unit's specified mounting pattern with proper isolators and tie into frame structure rather than into floor sheathing. A generator that works loose in its bay damages its own fuel line and wiring on the way out. The exhaust route has to terminate clear of every window, vent, door and slide opening, with the correct clearances from combustible material. This is the item we most often find wrong on a coach that was modified elsewhere, and it is not a cosmetic issue. Combustion air has to be equally deliberate, because a unit starved of air overheats, and a bay that recirculates its own exhaust is worse than that. ## Cost, hours and the LP caution The band on this page reflects a straight replacement of a like unit into an existing bay at the low end and a new installation into a coach with no generator prep at the top, where the fabrication, fuel supply, exhaust and transfer switch are all new work. Labor is the posted mechanical and electrical rate of $260 per hour across 10 to 45 hours, with unit lead time of 10 to 30 business days. On an LP fueled installation, the gas connection is certification gated. Tying a generator into a coach LP supply is LP work and it cannot legally be performed by an uncertified technician. On this site that connection is made by a certified LP technician and documented, and the rest of the installation proceeds around it. The estimate tier here is the RV systems estimate at $150, credited against an authorized job. On a from scratch installation we walk the bay with you before quoting, because available volume and a viable exhaust route are the two things that can turn a straightforward project into a no. ## Not included - We do not tie a generator into an LP supply without a certified LP technician performing the gas connection. - Chassis engine and drivetrain modifications are outside what this facility performs. - Portable generators strapped to a bumper or a rack are not an installation we take on. ## Questions **Can a generator be installed in a travel trailer or fifth wheel?** Often yes, and LP is usually the practical fuel because there is no chassis fuel tank to draw from. The constraints are bay volume, a viable exhaust route that clears every opening, and a combustion air path. We walk the coach before quoting, because those three items decide whether the project is straightforward or not worth doing. **What size generator do I need?** Start with how many air conditioners you intend to run at once, because they dominate everything else. One rooftop unit with a soft start plus normal coach load fits a smaller generator. Two rooftop units plus a water heater element and a microwave needs meaningfully more. We size to the actual load rather than to the largest unit that fits. **Where does the exhaust go and does it matter?** It matters more than any other detail. The outlet has to terminate clear of every window, vent, door and slide opening with correct clearance from combustible material. This is the item we most often find wrong on coaches modified elsewhere. A bay that recirculates its own exhaust is both a performance problem and a life safety problem. **Who makes the propane connection on an LP generator install?** A certified LP technician, because that connection is certification gated by law and cannot be performed by an uncertified technician regardless of skill. The mount, exhaust, wiring and transfer switch work proceeds around it. Ask any shop quoting an LP generator installation who specifically is making the gas connection, and expect a name and a certification. --- Source: https://ocrv.club/rv-service/generator-installation OCRV Center, 23281 La Palma Ave, Yorba Linda, CA 92887 Phone (949) 799-3387. Email info@ocrvcenter.com. Serving Hacienda Heights and the surrounding area. 18.4 miles, 24 to 38 minutes via SR-60 west to Fullerton Rd, then south to La Palma Ave. In shop work only. All estimates are priced and credited against an authorized repair.