Generator FAQ

It depends on what you want running at the same time rather than on your square footage. Essentials only, meaning refrigerator, furnace, internet and some lighting, needs about 10kW to 14kW. A typical San Diego house on 200 amp service with one air conditioning compressor lands on 22kW to 26kW. Add a second compressor, a pool, a well pump or an EV charger and you are into 30kW and up on a liquid-cooled unit. The number that matters is starting kW, not running kW, because motors draw two to three times their running figure for the first few seconds. Our site visit and load calculation are free.

A portable is a wheeled unit you store, roll out, fuel and start by hand, connected either by extension cords or through a permitted inlet and interlock. It costs a few hundred to a few thousand dollars and somebody has to be home. A standby unit is permanently installed on a pad, plumbed to natural gas or propane, and wired through an automatic transfer switch, so it starts within about ten seconds of an outage and shuts down on its own afterwards. Standby units are quieter, far more powerful and completely automatic.

Natural gas wherever a meter exists, because it never runs out, needs no tank and requires no deliveries during an emergency. Propane is the rural answer where there is no gas main, and it stores for years, but tank size sets your runtime so a 500 gallon tank beats a 250 for a multi-day shutoff. Diesel produces the most power per footprint and the best fuel efficiency, which is why commercial and industrial units use it, but it needs on-site storage and periodic fuel polishing to stay usable.

We install Generac, Kohler, Cummins, Champion and Briggs & Stratton generators. We service those plus Onan, Winco, Caterpillar, MTU and most other diesel and gas plant, whoever sold or installed it. Generac has the widest residential range and the deepest parts network in the county, Kohler runs heavier iron with a longer standard warranty, and Cummins is the standard engine family on the commercial and industrial side.

Most complete residential installs in San Diego County run between $5,000 and $15,000. A 14kW to 18kW unit on a simple natural gas lot with a load-center transfer switch sits near the bottom of that range; a 24kW to 26kW unit with a service-rated 200A automatic transfer switch, a long gas run and a panel upgrade sits near the top. The quote covers the generator, the pad, the gas line, the transfer switch, the electrical work, the permit and commissioning, itemized line by line.

The on-site work is one to three days for a residential standby unit. From signed quote to a commissioned generator, plan on four to eight weeks, most of which is permit turnaround plus lead time on the unit itself. HOA architectural review can add two to four weeks, so we submit that package alongside the permit rather than after it. Commercial and industrial projects run longer because of engineering, air district permitting and the shutdown window for the tie-in.

Yes. Every jurisdiction in San Diego County requires an electrical permit for the transfer switch and tie-in, plus a mechanical or plumbing permit for the gas line. Diesel units also need an air district permit. We pull all of them, submit the plan set, coordinate the inspection and handle corrections. An unpermitted transfer switch shows up during escrow and can complicate a homeowner insurance claim after a fire, so it is not a corner worth cutting.

It is the switch between the utility feed and your panel that decides which source powers the building. It watches utility voltage, signals the generator to start when the power drops, waits for the engine to stabilize, then moves your load across. When utility power returns and stays steady, it transfers back and shuts the generator down after a cooldown. It also physically prevents generator power from backfeeding onto the utility line, which is a safety requirement and the reason any permanent install needs one.

Manufacturers require roughly three feet of clearance at the sides and rear and five feet from any window, door or vent, with clear space overhead and nothing combustible against it. Local code adds distances from property lines, gas meters and air intakes. That usually means the side yard on suburban lots and the rear corner on narrow coastal lots in Encinitas, La Jolla, Coronado and older Chula Vista. Placement is checked on the site visit because it is the constraint that most often changes the design.

A modern air-cooled residential unit runs about 60 to 66 dB measured at 23 feet under load, which is roughly a central air conditioning condenser, and closer to 70 dB during its weekly exercise cycle, which lasts five to twelve minutes. Liquid-cooled and commercial units are louder and sit further from occupied space. We set the exercise cycle to a reasonable weekday hour and orient the exhaust away from neighboring windows, which prevents almost every noise complaint.

By size tier: a 20kW to 25kW towable unit is broadly $150 to $350 a day, 50kW to 100kW runs roughly $350 to $800 a day, and 150kW to 300kW is usually $800 to $1,800 a day. Anything from 400kW to 1MW is quoted individually and normally taken monthly. Weekly and monthly rates are much cheaper per day, with the crossover at about a week. Delivery, connection, a load test and collection are inside the rate.

Construction sites before the utility energizes the service, weddings and private events at ranch and estate venues, festivals and film production, planned utility shutdowns and panel upgrades, plant shutdowns and seasonal peaks, businesses covering a permanent unit that is down for repair, and properties pre-staging power for fire season shutoffs. Anything with an end date is almost always cheaper to rent than to own.

Single-day rentals arrive fueled and are returned as delivered, with fuel in the price. Multi-day and long-term rentals quote fuel separately on actual consumption, with scheduled refill delivery included in the rate and remote monitoring on the tank so we dispatch before you run low. Emergency same-day refills carry a trip charge because they sit outside the route. There is no environmental fee or fuel surcharge added at the end.

Annually at minimum for a residential standby unit: engine oil and filter, air and fuel filters, spark plugs, coolant, battery load test, transfer switch inspection and a run under load. Manufacturers also set hour-based intervals, typically an oil change every 100 to 200 running hours, and weekly exercise cycles accumulate those hours faster than owners expect. Commercial and code-mandated systems go on quarterly or semi-annual visits plus an annual load bank test. Missing annual service voids most warranties.

On natural gas, indefinitely, as long as the main stays live, which is why we prefer it wherever a meter exists. On propane, it comes down to tank size: a whole-house load burns roughly two to three gallons an hour, so a 500 gallon tank covers several days and a 250 gallon tank does not. A gasoline portable runs 8 to 12 hours per tank at half load. A diesel unit burns roughly 7 percent of its rated kW in gallons per hour at full load, so a 1,000 gallon tank on a 500kW machine gives about 28 hours flat out.

Appraisal data generally puts a permanently installed standby generator at roughly a 3 to 5 percent increase in home value, and homes with one tend to sell faster in areas that see regular outages. In the parts of San Diego County inside the public safety power shutoff footprint, Escondido, Poway, Ramona, Alpine and the eastern hills, buyers read it as infrastructure rather than a luxury feature. Keep the permit records and the service history, because that is what an appraiser will ask to see.

Yes. We work with several third-party lenders specializing in home improvement and standby power, with terms typically from 24 to 144 months on approved credit, including deferred-interest promotions at certain times of year. Manufacturers run their own rebates and financing offers periodically and we will tell you when one is live. Most households compare the monthly payment against what a single bad outage costs them in spoiled food, lost work and a hotel.

It depends where you are in the county. West of the 15 the grid is reasonably reliable and the honest answer for many households is a portable and an interlock rather than an automatic install. East of it, inside the shutoff footprint, outages are planned, long and reliably timed for the hottest, windiest week of the year, and the calculation looks completely different. We will tell you which side of that line your address sits on before quoting anything.

It depends on what you want running at once rather than on the square footage. Essentials only, meaning refrigerator, furnace, some lighting and a few outlets, needs about 10kW to 14kW. A typical San Diego house with 200 amp service, one air conditioning compressor, a range and normal appliances lands on 22kW to 26kW. Add a second compressor, a pool, a well pump or an EV charger and you are looking at 30kW and up in a liquid-cooled unit. We do a free load calculation that counts motor starting loads, which is where undersized quotes usually go wrong.

A portable generator is a wheeled unit you store in the garage, roll out during an outage, fuel with gasoline or propane, and connect either through extension cords or through an inlet and interlock kit. It costs a few hundred to a few thousand dollars and somebody has to be home to run it. A standby generator is permanently installed on a pad, connected to natural gas or propane, and wired through an automatic transfer switch, so it starts on its own within about ten seconds of an outage and shuts down on its own when the utility returns. Standby units are quieter, far more powerful, and need no attention during the outage at all.

Natural gas wherever you have a meter. It never runs out, needs no tank and requires no deliveries, which makes it the obvious choice for most homes in San Diego, Chula Vista, Carlsbad and Poway. Propane is the answer on rural parcels with no gas main, and it stores well for years, but the tank size sets your runtime so a 500 gallon tank is worth the extra cost over a 250. Diesel is more efficient per gallon and much more powerful, which is why industrial and large commercial units use it, but it needs a fuel tank, periodic fuel polishing and more maintenance than a homeowner usually wants.

We install Generac, Kohler, Cummins, Briggs & Stratton and Champion generators, and we service those plus Onan, Winco and most diesel units regardless of who sold them. Generac has the widest residential range and the biggest parts network locally. Kohler runs heavier iron with a longer standard warranty. Cummins generator installation is what we suggest when somebody wants the commercial engine family at home. We are not tied to one manufacturer, so the recommendation follows your fuel and your load.

Most complete installs in San Diego County run between $5,000 and $15,000. A 14kW to 18kW unit on a simple natural gas lot with a load-center transfer switch sits near the bottom of that range. A 24kW to 26kW unit with a service-rated 200A automatic transfer switch, a long gas run and a panel upgrade sits near the top. Liquid-cooled units above 30kW go beyond it. The quote covers the generator, the pad, the gas line, the transfer switch, the electrical work, the permit and commissioning, itemized so you can see where the money goes.

The on-site work is usually one to three days. The whole project, from signed quote to a commissioned unit, typically runs four to eight weeks, and most of that is permit turnaround plus unit lead time on anything not already in the warehouse. HOA architectural review can add two to four weeks on top, which is why we submit that package at the same time as the permit rather than after it.

Yes. Every jurisdiction in the county requires an electrical permit for the transfer switch and the tie-in, and a mechanical or plumbing permit for the gas line. We pull both, submit the plan set, coordinate the inspection and handle any corrections. Permit fees vary by city and are itemized in the quote. Skipping the permit creates a real problem later, because an unpermitted transfer switch shows up in escrow and can void a homeowner insurance claim after a fire.

It is a switch that sits between the utility feed and your panel and decides which source powers the house. When it sees the utility voltage drop, it signals the generator to start, waits for the engine to come up to speed and stabilize, then transfers your load onto generator power. When utility power comes back and stays steady, it transfers you back and shuts the generator down after a cooldown. It also physically prevents generator power from backfeeding onto the utility line, which is a safety requirement and the reason a permanent install legally needs one. Without it you are running extension cords by hand.

Manufacturers require roughly three feet of clearance at the sides and rear and five feet from any window, door or vent, with clear space above and nothing combustible against it. Local code adds distances from property lines, gas meters and air intakes. In practice that means the side yard on most suburban lots, and the rear corner on narrow coastal lots in Encinitas, La Jolla, Coronado and the older parts of Chula Vista. We check placement on the site visit, because it is the constraint that most often changes the design.

Modern air-cooled standby units run about 60 to 66 dB measured at 23 feet under normal load, which is roughly the same as a central air conditioning condenser and quieter than a lawn mower. The weekly exercise cycle is closer to 70 dB but only lasts five to twelve minutes. Liquid-cooled units are louder and generally sit further from occupied space. We set the exercise cycle to a reasonable weekday hour and orient the exhaust away from neighboring windows, which handles almost every noise complaint before it happens.

Appraisers and real estate data generally put a permanently installed standby generator at roughly a 3 to 5 percent increase in home value, and homes with one tend to sell faster in areas where outages are common. In the parts of San Diego County that sit inside the public safety power shutoff footprint, Escondido, Poway, Ramona, Alpine and the eastern hills, it reads to buyers as infrastructure rather than a luxury. Keep the permit records and the service history, because that is what an appraiser will actually want to see.

Yes. We work with several third-party lenders that specialize in home improvement and standby power, and terms typically run from 24 to 144 months with approved credit, including deferred-interest promotional options at certain times of year. Manufacturers also run periodic rebates and financing promotions, and we will tell you when one is live rather than letting you miss it. Most households compare a monthly payment against what one bad outage costs them and decide from there. Call for a free estimate and we will lay out the options with the quote.

Add up the running watts of everything you want on at the same time, then add the starting surge of the largest motor, which is typically two to three times its running figure. Essentials only, meaning a refrigerator, a furnace blower, the internet and some lighting, is usually 3kW to 5kW. Add well pump or air conditioning and you are at 7kW to 12kW on a portable or 14kW and up on a standby unit. A free load calculation takes us about twenty minutes on site and stops you buying the wrong thing.

You can, and plenty of people do, but it limits you to whatever reaches and it leaves out anything hardwired, which means no furnace, no well pump and no lighting circuits. Never connect a portable to a wall outlet to feed the panel. That backfeeds the utility line, can kill a lineman working on the outage, and can destroy your generator when power returns. A permitted inlet and interlock is a few hundred dollars and solves the problem properly.

A gasoline portable runs 8 to 12 hours on a tank at half load and should be shut down and cooled before refueling. Propane depends on the tank: about 5 to 8 hours on a 20lb cylinder, several days on a 500 gallon residential tank. A natural gas standby unit runs indefinitely as long as the gas main is live, which is the main reason we prefer it wherever a meter exists. Diesel units are the most fuel-efficient and are what we use for multi-week jobs.

They are, with two rules that are not negotiable. Run it outdoors only, at least 20 feet from the house with the exhaust pointing away, because carbon monoxide from a portable running in a garage or under an eave kills people every winter in the United States. And connect it through a permitted inlet and interlock rather than into a wall receptacle. Beyond that, keep it dry, keep fuel stored safely, and let it cool before refueling.

A single central air conditioning compressor typically needs 3kW to 5kW running and two to three times that for the few seconds it starts, so realistically you need a 14kW or larger standby unit, or a very large portable with a soft-start module installed on the compressor. Soft-start kits are inexpensive and cut the surge substantially, which sometimes brings air conditioning within reach of a unit that could not otherwise carry it. In San Diego summers this is worth asking about specifically.

Yes, and the units that fail during an outage are almost always the ones nobody touched. A standby unit exercises itself weekly and needs an annual service: oil, filter, plugs, battery test and a run under load. A portable needs the fuel stabilized or drained, the oil changed every 50 to 100 running hours, and a start every few months. A dead battery and stale fuel are the two most common reasons a generator does not start when it is finally needed.

It comes from a load study rather than from the service size. We look at the connected load, the actual demand profile, the starting characteristics of the largest motors, and any harmonic or non-linear load from variable frequency drives and UPS systems. Where the profile is not documented we log real demand on site for a week. Sizing off the main breaker rating is how facilities end up with a machine twice the size they need that then wet stacks because it never sees load.

Standby rating covers emergency use with a varying load and limited annual run hours. Prime rating covers unlimited hours at a varying load, which is what a site with no utility connection needs. Continuous rating covers a constant load indefinitely, typically for base-load generation. The same engine is rated lower as you move from standby to continuous, because the harder the duty, the more margin it needs. Buying a standby-rated machine for prime duty shortens its life dramatically.

Annually for most facilities, and it is a legal requirement for code-mandated emergency systems such as hospitals, high-rise life safety and certain telecom and data sites. NFPA 110 sets out monthly exercise requirements plus an annual test at load. Beyond compliance, an annual load bank test is what proves a lightly loaded standby unit will actually carry the facility, and it burns off the carbon build-up from years of light-load exercise runs.

In San Diego County, almost certainly yes. The air district permits stationary diesel engines, and the requirements differ between emergency standby use, which has permitted hour limits for testing and maintenance, and prime power, which is regulated more tightly. Tier 4 Final certification is required for many applications and for most public works contracts. We check this before specifying anything, because the emissions requirement can dictate the equipment.

A rough rule for diesel is about 7 percent of the rated kW in gallons per hour at full load, so a 500kW unit burns roughly 35 gallons an hour flat out and considerably less at partial load. A 1,000 gallon base tank on that machine gives about 28 hours at full load. Most facilities specify 24 to 72 hours of on-site storage and arrange a fuel contract for anything longer, which we set up as part of the service agreement.

Yes, whoever built it and whoever installed it. Our techs work on Cummins, Caterpillar, Kohler, MTU, Detroit and Onan diesel plant regularly, and we carry the common wear parts on the truck. If a unit is beyond economical repair we will say so with the numbers rather than quoting a rebuild that costs most of a replacement. While it is down we can stage a rental unit so the facility is not exposed.

Start by separating the critical load from the rest of the building. Walk the panel schedules and mark what genuinely has to stay live: refrigeration, life safety, point of sale, servers, phones, emergency lighting and any process that is damaged by interruption. That subtotal, plus the starting surge of the largest motor, sets the generator size. Most businesses find the critical load is a third to a half of their service size, which changes the price dramatically.

Semi-annually at minimum, and quarterly for units on code-mandated or high-value duty. A standard visit covers oil and filter change, air and fuel filters, coolant condition and level, belts and hoses, battery load test, controller fault history, transfer switch inspection and a run under load. Emergency systems also need a monthly exercise and an annual load bank test. Most manufacturer warranties require documented annual service, so the contract protects the warranty as well as the equipment.

Regularly. It needs the landlord or property manager on board, and the lease usually governs where the unit can sit, who owns it at the end of the term and who is responsible for restoring the site. We have done plenty of tenant installs where the unit is designed to be removable, and plenty where the landlord funded it as a building improvement. Worth having that conversation before the design is finished rather than after.

Either, and the choice is yours once you see both numbers. Whole-building coverage through a service-rated transfer switch is simplest to operate and most expensive. A dedicated emergency panel fed from a smaller unit covers the circuits you selected at a fraction of the cost. A middle option uses load shedding controls so a smaller generator carries the building by dropping non-essential loads automatically when demand rises.

Contract customers get priority dispatch with a defined response time. If the unit needs parts or a rebuild, we stage a towable rental generator on site so the business keeps running while the permanent one is repaired. That is the main practical reason to have a service agreement with a company that also holds a rental fleet rather than one that only does installs.

Diesel units do. The San Diego air district permits stationary diesel engines, with limits on annual run hours for emergency standby use and stricter requirements for anything running as prime power. Natural gas units face lighter requirements in most cases. We check permitting before specifying equipment, and the application goes in with the building and electrical permits rather than afterwards.

Once a year at minimum for a residential standby unit, which covers oil and filter, air and fuel filters, spark plugs, coolant, battery load test, transfer switch inspection and a run under load. Manufacturers also specify hour-based intervals, typically an oil change every 100 to 200 running hours, and the weekly exercise cycle accumulates those hours faster than people expect. Commercial and code-mandated systems go on semi-annual or quarterly visits plus an annual load bank test. Skipping annual service voids most manufacturer warranties.

In rough order of frequency: a dead or weak battery, stale fuel and a varnished carburetor on a gas unit that never ran under load, low oil or coolant tripping a safety shutdown, a blocked fuel filter on a diesel, and a controller fault or a switch left in the wrong position after somebody worked on it. Almost all of those are cheap to prevent and irritating to discover during an outage, which is the whole argument for annual servicing.

Yes, and most of our repair work is on units somebody else sold. We service Generac, Kohler, Cummins, Onan, Champion, Briggs & Stratton, Caterpillar, MTU and most other brands regardless of origin. We carry common wear parts on the truck and can order almost anything else for next-day delivery. Being outside the original warranty does not stop us working on it.

Contract customers get priority dispatch, and within the San Diego metro that usually means same day. Non-contract emergency calls are worked in as the schedule allows, which is often same day and occasionally next. If the repair needs a part we do not have, we can stage a rental unit on site so a business with refrigeration or a household with medical equipment is not exposed while we wait for it.

A standard annual visit on a residential air-cooled standby unit is a flat rate that covers oil and filter, air and fuel filters, plugs, battery test, transfer switch inspection and a run under load. Larger liquid-cooled and diesel units cost more because they take more oil, more coolant and more time. Annual plans work out cheaper per visit than single service calls and include priority response. Call and we will quote for your specific unit.

It depends on hours, condition and what has failed. A fifteen-year-old air-cooled residential unit needing a controller and an alternator is usually not worth it, because the parts approach the cost of a new machine with a fresh warranty and better fuel efficiency. A well-maintained liquid-cooled or diesel unit with thousands of hours left in the block is almost always worth repairing. We give you both numbers and let you decide rather than steering you toward the sale.

It goes by size tier and duration. A 20kW to 25kW towable unit for a wedding or a small job site is broadly $150 to $350 a day. A 50kW to 100kW unit runs roughly $350 to $800 a day. A 150kW to 300kW unit is usually $800 to $1,800 a day, and anything from 400kW to 1MW is quoted individually. Weekly and monthly rates are much cheaper per day than daily rates, with the crossover at about a week. Every quote includes delivery, connection, a load test and collection.

Construction sites before the utility energizes the service, weddings and private events at ranch and estate venues, festivals, film and television production, farmers markets and food vendor rows, planned utility shutdowns and panel upgrades, plant shutdowns and seasonal peaks, businesses covering a permanent unit that is down for repair, and properties pre-staging power for fire season shutoffs. Anything with an end date is usually cheaper to rent than to own.

Single-day rentals arrive fueled and are returned as delivered, with fuel included. Multi-day and long-term rentals quote fuel as a separate line, metered on actual consumption, with scheduled refill delivery included in the rate. Remote monitoring tracks the tank level so we dispatch before you run low. Emergency same-day refills outside the schedule carry a trip charge, and there is no environmental fee or fuel surcharge added at the end of the rental.

Send us the equipment list rather than the square footage. We calculate running kW for everything on at once, then add the starting surge of the largest motor, which for a compressor, a pump or a crane is several times its running figure. A wedding with catering, lighting and sound is usually 20kW to 40kW. A mid-size construction site is 50kW to 150kW. A commercial building on critical load is 100kW to 300kW. Undersizing is the most common rental mistake and it shows up as a unit that stalls every time something starts.

Most rentals go out next day, and same day is often possible when the size you need is on the yard. Call in the morning and we will tell you honestly what is available. Larger units, sound-attenuated event units and busy spring and summer weekends book further ahead, so anything with a fixed date is worth reserving early rather than assuming.

The sound-attenuated units are, which is why we use them for anything with a ceremony, a speech or a recorded performance attached. A standard construction-spec unit is not, and putting one behind a marquee is a mistake people only make once. We also place event units downwind and out of sight, and deliver hours ahead of guests so there is time to move anything that is not right.