Generator FAQ

It comes off a load calculation at your panel, not off the square footage. A typical San Francisco house with gas heat and a gas range is comfortable on 14kW to 18kW. Houses with a heat pump, an induction range or an EV charger generally need 22kW to 26kW. Anything above that moves into liquid-cooled equipment and a different price class. We measure what is actually connected before quoting a size.

A portable is wheeled out, started and refuelled by hand, runs on gasoline or propane, and feeds a few circuits through a cord or an inlet box. A standby unit is bolted to a pad, plumbed into natural gas, starts itself about ten seconds into an outage with nobody home, and feeds whatever the transfer switch is wired to. The deciding question is usually whether somebody will reliably be there to operate it.

For a home in San Francisco, natural gas, almost always: the main is already there, nothing is stored, nothing goes stale and runtime is unlimited. Propane is the answer where gas service is genuinely absent, at roughly a ten percent power penalty and with a tank to refill. Diesel belongs on commercial and industrial sites, where its power density and on-site fuel are worth the storage, noise and emissions obligations.

We install and warranty Generac, Kohler, Cummins and Champion generators, and we service those plus Honda, Briggs and Stratton, Onan and most older equipment still running behind Bay Area buildings. Generac has the deepest parts network locally, Kohler runs quieter for the same output, Cummins suits commercial and larger loads, and Champion is the value option for a modest house.

Between about $5,000 and $15,000 in this market, permitted and commissioned. The low end is a 14kW air-cooled unit with a critical-loads transfer switch, a short gas run and an easy pad. The high end is a 26kW unit with a 200-amp service switch, a long upsized gas line and a service upgrade first. Our number includes permits, commissioning and the first year of maintenance.

Three to six weeks from order to running. Equipment lead time on common air-cooled sizes is one to three weeks and the permit runs alongside it. The install itself is one long day for a straightforward job, two if a service upgrade or an awkward gas run is involved, and inspection follows within a week or two depending on the jurisdiction.

Yes, everywhere we work. A standby install needs an electrical permit and a mechanical or plumbing permit for the gas connection, and the finished work is inspected. Several jurisdictions also check placement against setback and noise rules. We pull the permits and meet the inspector, because an unpermitted generator turns into an expensive discovery during escrow.

It watches utility voltage, and when the grid drops it disconnects your building from the utility, starts the generator and connects the building to it — usually within ten seconds. When utility power returns and holds, it transfers back and runs the engine down on a cooldown cycle. The utility disconnect is the critical part: it is what stops your generator energizing the line outside and injuring somebody working on it.

Outside, on level ground, away from openable windows, doors and vents, clear of the property line, with the manufacturer’s clearance on every side for airflow and service access. Five feet from openings and eighteen inches from the wall is the common rule of thumb, but the binding numbers come from the equipment listing and local code — and on tight city lots that combination often rules out the obvious spot next to the meter.

Roughly 60 to 70 decibels at seven metres for a modern air-cooled unit, which sits between a normal conversation and a window air conditioner. Kohler units and enclosed liquid-cooled sets are at the quieter end, and sound-attenuated enclosures exist for commercial machines in mixed-use blocks. The weekly exercise run lasts about twelve minutes and can be scheduled for a reasonable hour.

A home standby unit wants a full service once a year — oil and filter, air filter, plugs, belts, hoses, battery test, coolant, and a run under load — plus the weekly exercise cycle the controller does by itself. Commercial sets want a minor service twice a year and a major service annually, and anything on a critical load should also get a load-bank test each year.

A natural gas standby unit runs indefinitely while the gas main is live, which is why it is the default in this city. A diesel set runs as long as its tank lasts, typically a day or two on a sub-base tank before refuelling. A propane unit depends on tank size. A gasoline portable manages eight to twelve hours per tank and has to be refuelled by hand.

Generally yes, and in outage-prone parts of the Bay Area it is one of the improvements buyers actively look for. Industry surveys put the effect at around three to five percent of home value, and appraisers treat a permitted, professionally installed unit as a permanent improvement rather than a maintenance liability. The permitted part is what makes the difference.

Yes. Most customers use manufacturer-backed financing through the Generac or Kohler programs, a home improvement loan, or a HELOC, and the monthly figure on a typical whole-house install lands in the same range as a phone bill. We will break the quote into equipment, electrical and permit lines so a lender can see precisely what is being financed.

It comes off a load calculation, not the square footage. A typical San Francisco house with gas heat and a gas range is comfortable on 14kW to 18kW. An all-electric house, or one with a heat pump, an induction range or an EV charger, is usually 22kW to 26kW. Above that the equipment goes liquid-cooled and the price class changes. We measure the actual connected load at your panel and tell you which band you are in before quoting anything.

Between about $5,000 and $15,000 in this market, all in. The low end is a 14kW air-cooled unit with a critical-loads transfer switch, a short gas run and an easy pad. The high end is a 26kW unit with a 200-amp service transfer switch, a long upsized gas line and a service upgrade. Permits, commissioning and the first year of maintenance are inside our number rather than added afterward.

Three to six weeks in most cases. Equipment lead time on common air-cooled sizes is one to three weeks, the permit runs alongside that, and the install itself is one long day for a straightforward job or two if a service upgrade or an awkward gas run is involved. Inspection follows within a week or two depending on the jurisdiction.

Yes. A standby install needs an electrical permit and a mechanical or plumbing permit for the gas connection, and the work is inspected. Every jurisdiction we cover requires it, and several also check placement against setback and noise rules. We pull the permits, meet the inspector and hand you the signed card, because an unpermitted generator becomes an expensive problem at resale.

It is the device that isolates your house from the utility and connects it to the generator. It senses the outage, starts the engine, transfers the load in about ten seconds, and reverses all of that when the grid comes back. Yes, you need one — a permanently installed generator without a listed transfer switch can backfeed the utility line and injure a lineman, which is why no inspector will pass it.

On level ground outside, away from openable windows, doors and vents, clear of the property line, with manufacturer clearance on all sides for airflow and service access. The typical requirement is five feet from openings and eighteen inches from the wall, but the binding numbers come from the manufacturer listing and the local code, and on tight city lots that combination frequently rules out the obvious spot. We check it on the estimate visit rather than on install day.

Around 60 to 70 decibels measured at seven metres for a modern air-cooled unit, which sits between normal conversation and a window air conditioner. Kohler and the enclosed liquid-cooled sets are at the quieter end. The weekly exercise cycle runs about twelve minutes and can be scheduled for a civilised hour, which on a dense block matters more than the raw number does.

Generally yes, and in outage-prone parts of the Bay Area it is one of the additions buyers actively search for. Industry surveys put the effect in the region of three to five percent of home value, and appraisers treat a permitted, professionally installed unit as a permanent improvement. The word doing the work in that sentence is permitted — an unpermitted install shows up as a liability during escrow instead.

Yes. Most customers use manufacturer-backed financing through the Generac and Kohler programs, a home improvement loan or a HELOC, and for a typical whole-house install the monthly figure lands in the same range as a phone bill. We are happy to break the quote into equipment, electrical and permit lines so a lender can see exactly what is being financed.

A portable is wheeled out, started by hand and refueled by hand, runs on gasoline or propane, and feeds a few circuits through a cord or an inlet. A standby unit is bolted to a pad, plumbed into natural gas, starts itself about ten seconds after an outage with nobody home, and feeds whatever the transfer switch is wired to. The deciding question is usually whether somebody will reliably be there to operate it.

For a permanent unit in San Francisco, natural gas — the main is already there, nothing is stored, nothing goes stale and runtime is unlimited. For a portable, dual fuel: propane for storage life and clean burning, gasoline when propane is not to hand. Diesel is the right answer on commercial and industrial sites and the wrong one behind a house, because of fuel storage, noise and emissions rules.

A mid-size portable at half load gets roughly eight to twelve hours from a full gasoline tank and about ten hours from a twenty-pound propane cylinder, so an overnight outage needs a second cylinder ready. Inverter units use noticeably less at light load. A natural gas standby unit runs indefinitely while the gas main is live, and a diesel set runs as long as its tank lasts, typically sized for a full day at load.

No. Feeding a house through a dryer or range outlet with a double-male cord energizes the utility line outside and can kill a lineman working on it, and it bypasses every protection in your panel. The legal options are an inlet box with a panel interlock, a manual transfer switch, or an automatic transfer switch. Fitting one is usually a few hundred dollars of work and it is the single most worthwhile thing you can do with a generator you already own.

We install and service Generac, Kohler, Cummins and Champion generators, and we service Honda, Briggs and Stratton, Onan and most other makes we come across on portables and older standby units. We are not tied to one brand: Generac has the widest parts network locally, Kohler runs quieter, Cummins suits larger and commercial loads, and Champion is the value choice for a modest house.

Outdoors, at least twenty feet from the building, with the exhaust pointing away from every door, window and vent, on level ground, under a proper open-sided generator cover if it is raining. Never in a garage, never under a deck, never in a doorway or a partly open space. Carbon monoxide from portable generators kills people every winter and it is always the same mistake.

It comes from a measured load study, not a nameplate total. We record actual demand over a representative period, check the starting kVA of the largest motors, add whatever code obliges you to back up, and allow headroom for growth. Adding nameplates typically oversizes a set by a wide margin, and an oversized diesel running lightly loaded wet-stacks and fails early, so oversizing is not a safe error.

Diesel for most: higher power density, better step-load acceptance and fuel that is already on site rather than dependent on a utility that may be affected by the same event. Natural gas where the load steps are gentle, the main is dependable and you would rather have no fuel storage, no tank regulations and cleaner emissions. Bi-fuel is worth pricing where the required runtime is long.

A load bank applies a real, controlled electrical load so the set runs at rated capacity and you find out whether it holds. Annually is the standard for anything on a life-safety or high-value load, and it is also what clears the carbon build-up that light-load running causes on diesels. A monthly no-load exercise run proves the engine starts and almost nothing else.

Almost certainly, yes. Stationary engines are registered or permitted through the Bay Area Air Quality Management District, with conditions on emissions tier, annual operating hours and record keeping, and standby-only sets sit under different limits from prime-power ones. We handle registration, hour logs and annual reporting for customers who want that off their desk.

Yes, and it is the normal way to handle a failed set, a switchgear upgrade or a planned shutdown. We size the rental to the load, deliver a trailer-mounted set, cable it into your gear, test it and take it away afterward. On planned work we like it on site and proven the day before rather than the morning of.

Diesel sets on standby duty want a minor service twice a year and a major service annually, plus an annual load-bank test. Sets that run more hours move onto an interval based on hours rather than the calendar. Fuel testing and polishing belong on the same schedule, because degraded fuel is the most common cause of a set failing when it is finally called on.

Smaller than most people assume, because it should be sized to what must stay on rather than to your electrical service. A restaurant backing refrigeration, the walk-in, hood and make-up air, registers, network and lighting is usually 40kW to 60kW. Adding air conditioning and the general-purpose circuits is what pushes a quote toward 150kW, and for most businesses that money buys comfort nobody would miss for an hour.

A minor service twice a year, a major service annually, and an annual load-bank test where the load is critical or code-required. Minor covers oil and filters, belts, hoses, battery, coolant and a run under load; major adds valve and injector checks, coolant and fuel analysis and a full electrical inspection. Life-safety installations also carry mandated exercise intervals with written records.

Yes, and a good share of our commercial work is exactly that. The first visit is a full inspection plus a load test, so we both find out honestly what condition the machine is in before anyone commits to a plan. If it needs work we quote it; if it is fine we say so and put it on a schedule.

Nearly all of it, yes. The pad, the machine, the fuel connection, the exhaust and most of the electrical happen while you trade. The one part that needs power off is the transfer switch cut-over at the service, which is typically a few hours, and we schedule that overnight or on a closed day.

Yes: electrical and mechanical permits as standard, air-district registration or permitting for diesel sets, structural review for roof and mezzanine installations, and life-safety review where the generator backs emergency systems. We pull them, meet the inspectors and hand over the signed records, which is also what your insurer will eventually ask to see.

Call us: we run 24/7 emergency generator repair and carry common controller, battery, starting and fuel-system parts on the vans, which is what most no-start failures come down to. If the set cannot be recovered quickly we will get a rental unit to the site and cable it in so the business keeps trading while we deal with the repair properly.

A residential standby unit wants a full service once a year and a short exercise run weekly, which the controller does by itself. Commercial sets want a minor service twice a year and a major service annually. Anything on a life-safety or high-value load should also get a load-bank test each year. Sets that run real hours follow an hours-based interval instead of the calendar.

Annually, or every 100 to 200 running hours, whichever comes first — and for nearly every home standby unit it is the year that comes first. Short exercise cycles never get the oil properly hot, so moisture and combustion by-products build up even with almost no hours on the meter. Diesel sets running real load follow their hour intervals closely.

A natural gas standby unit runs indefinitely while the gas main is live, which is why it is the default in this city. A diesel set runs as long as its tank holds out, typically twenty-four to forty-eight hours on a sub-base tank before it needs refuelling. A propane unit depends entirely on tank size. A gasoline portable is eight to twelve hours a tank and needs refuelling by hand, in the dark, in the rain.

In order of likelihood: the battery, the fuel, or a controller sitting in a fault state. Batteries last three to five years and fail without warning under a real cold start. Fuel means stale gasoline, degraded diesel, plugged filters or a gas valve closed during unrelated work. Beyond that it is starters, solenoids, control boards and wiring. We diagnose before quoting rather than replacing parts hopefully.

Yes, and it is a large share of what we do. We work on Generac, Kohler, Cummins, Champion, Honda, Briggs and Stratton and Onan equipment, residential through industrial, whoever installed it. On a machine we have not seen before the first visit includes a full inspection and a load test so nobody is guessing about its condition.

Depends on the class of machine. Industrial diesel plant is designed to be rebuilt and is frequently worth repairing at twenty-five years. A fifteen-year-old air-cooled residential set needing an alternator or a control board usually is not, because the repair approaches the cost of a new unit with a new warranty. We will tell you which one you have, including when that answer loses us the work.

It is priced by size tier and duration. A 20kW to 45kW unit runs a few hundred dollars a day or around a thousand a month; a 60kW to 125kW unit is mid-hundreds daily and low thousands monthly; anything from 150kW up is quoted per job. Monthly is dramatically cheaper per day than daily, and the crossover is at about a week, so tell us the real duration rather than the optimistic one.

It depends on running load and starting load, and starting load is what catches people out — motors, compressors and lifts draw several times their running current for a moment. Give us a list of what will be plugged in and we will size it. Most jobs come out smaller than the customer expected, and an over-specified machine costs more to rent and burns more fuel.

Construction sites with no permanent service, weddings and events at venues without enough power, film and photography shoots, planned utility shutdowns, buildings whose own generator has failed, seasonal peaks, markets and fairgrounds, and emergency staging. If it is temporary, or it only happens a few times a year, renting almost always beats owning.

Machines are delivered full. On short rentals you return it full, or we refuel and bill the fuel at cost plus a delivery charge — it is written on the agreement rather than hidden in it. On rentals of a month or more we schedule deliveries and monitor the tank level remotely, so we top it up before the site stops rather than after.

If it is the right machine, yes. A standard construction unit is audible and unpleasant from fifty feet; a super-quiet event generator at the same output sits under normal conversation and disappears once music starts. We also site it downwind, out of sightlines, with the cable run properly. Say it is a wedding when you call and we will quote the right class of machine.

Yes, all three, and the connection is the part that matters. We position the unit for exhaust and noise rather than for the convenience of the truck, land the leads, tie the grounds, set up distribution and load-test it before leaving. On events we do all of that the day before wherever the venue allows.