List everything you want to run at the same time and note each item’s running watts. Add them up, then add the biggest start-up surge: fridges, freezers and pumps briefly draw several times their running power as their motors kick in. Divide the total by 1,000 to get kilowatts and add a 20% safety margin.

Generators in Ireland are usually sold in kVA, so divide kW by 0.8 to convert. For example, 6 kW of load plus 20% is 7.2 kW, or 9 kVA, so you’d pick a 10 kVA generator.

For anything bigger than a house, or if you’re not sure, we’ll size it properly on a site visit.

kW (kilowatts) is the real power your appliances turn into heat, light and motion. kVA (kilovolt-amperes) is the total power a generator has to supply, including the extra current that motors and electronics draw without doing useful work. The ratio between the two is the power factor.

Most diesel generators are rated at a power factor of 0.8, so a 10 kVA generator delivers about 8 kW and a 100 kVA set about 80 kW. When you compare a generator against your list of appliances, convert both to the same unit first.

Match the generator to your electricity supply. Most Irish homes have a single-phase 230 V supply, so a single-phase generator is the norm for house backup. Farms, factories and larger businesses often have a three-phase 400 V supply for big motors, milking equipment and compressors, and need a three-phase generator to back it up.

Some generators can provide both. If you’re not sure which supply you have, your electrician can tell you in minutes, or give us a call and we’ll help you check.

A 3 kVA generator gives you roughly 2.4–3 kW. That suits a caravan or campervan, a market stall, power tools on site, or the basics in a power cut: fridge-freezer, lights, Wi-Fi and phone charging. It will also handle power-hungry appliances like a microwave, coffee machine or hair dryer, one at a time.

It won’t run an electric shower, immersion or electric cooker, and a 3 kW kettle on its own will use most of its output.

For the essentials in a typical Irish home (fridge-freezer, lights, Wi-Fi, TV, oil or gas boiler and the occasional kettle), a generator that provides 5,000 to 8,000 watts, or about 6.5–10 kVA, is usually enough.

If you want a standby generator that runs the whole house as normal, including an electric shower, immersion or heat pump, you’re looking at roughly 15–25 kVA. Many people choose the middle ground: back up the essentials and skip the big heating loads during an outage. The quick load check gives you a figure for your own house.

Yes, comfortably. A 25 kW generator (about 31 kVA) will run almost any Irish home as normal, with an electric shower, heat pump, immersion and cooker on alongside the lights and appliances.

For most houses it’s more than you need, so it costs more to buy and burns more fuel at light loads than a smaller set. Before you buy, check it matches your supply: most homes are single-phase, while many generators this size are three-phase.

A fridge uses only 100–250 watts once it’s running, but its compressor needs several times that for a second or two when it starts. Even a 2–3 kVA generator can run a fridge-freezer on its own.

To keep the fridge and freezer going alongside your lighting circuits and other critical equipment, choose a generator rated at 5,000 to 7,500 watts. One with around 7,500 running watts can run all of these at once.

Yes, but it needs to be a big one. Electric showers in Irish homes are usually rated at 8.5–10.5 kW, more than everything else a house typically uses during a power cut. To run a shower plus the essentials, you’ll need at least a 15 kVA standby generator, and 20 kVA gives comfortable headroom.

If your budget is tight, it’s usually cheaper to leave the shower off the generator circuits and size for the essentials instead. Your electrician can set this up when the changeover switch goes in.

Start with a list of what must keep running in an outage and the running wattage of each item. Add the numbers together, allow for start-up surges and a 20% margin, and that tells you what size generator is right for you. The more appliances you want to use at once, the bigger the generator you’ll need.

Then decide on fuel (diesel for long or frequent use), a portable unit or a fixed standby generator, single- or three-phase, and how it will connect to your wiring. For anything wired into the house, that means a changeover switch. Our guide to buying a generator in Ireland goes into more detail.

Any generator can provide backup power, but an emergency generator is part of a life-safety system. It powers things like emergency lighting, fire systems and medical equipment, so it must start and take the load within seconds. A standby generator keeps normal operations running and can respond more slowly.

Under widely used US codes, legally required standby systems have 60 seconds to transfer the load, while emergency systems have just 10. Standby systems cost less; emergency systems need faster switching, more monitoring and regular testing.

Yes. We’ll visit your premises, look at what needs to stay powered, check your supply and where a generator could sit, and talk you through the options, from new or used diesel generators to hire. In most cases we can source any generator that fits your needs.

We can also help with installation, servicing and maintenance afterwards. Call 05394 21599 or request a quote to book a visit. For factories, our guide to power outage protection for manufacturing facilities covers the planning in more detail.

Size it for the loads you can’t do without during an outage: the milking machine, bulk tank cooling, water heating, water pumps and lights. Dairy farms commonly use a PTO generator somewhere in the 20–60 kVA range, but your parlour and tank make a big difference.

Then check the tractor. Allow roughly 2 hp for every kW of generator output, so a 30 kVA (24 kW) PTO generator needs a tractor of about 50 hp, running at the correct PTO speed. Match the generator to your supply, single- or three-phase. See our farm and PTO generators in Gorey.

It depends on the building and what must stay on, but an average-sized hospital typically needs around 1,250 kW of backup power. That capacity is usually split across several diesel generators, so one can fail or be serviced without the hospital losing power.

Smaller sites such as clinics and nursing homes need far less, and every medical facility is different, so the final size comes from a proper load assessment. Our range runs from 10 kVA up to 5,000 kVA.

Most hospitals rely on diesel generators. A diesel generator starts quickly, takes a heavy load within seconds, stores its own fuel on site and is built for long runs, which is exactly what critical care needs. Modern sets also offer high efficiency and low fuel consumption for their size.

Hospital sets are typically paired with automatic transfer switches and tested on load regularly. The largest industrial units run to several megawatts each.

For anything beyond occasional, short use, diesel. A diesel generator uses less fuel for the power it makes, lasts far longer, copes with heavy loads and long runs, and diesel is safer to store than petrol. That’s why almost every standby generator, farm set and industrial unit runs on diesel.

Petrol generators are cheaper, lighter and quieter at small sizes, which makes them fine for camping, a market stall or a few hours of backup. Petrol goes stale in storage, though, so a petrol unit kept for emergencies needs fresh fuel and regular runs.

It depends on the fuel, the tank and how hard it’s working. As a rule of thumb, a 5 kW diesel generator burns about 1–2 litres an hour: roughly 1 litre at half load and closer to 2 at full load.

A built-in 15-litre tank therefore lasts about 8–15 hours, and a 100-litre external tank keeps it going for two to four days. Petrol and LPG (propane) generators burn more fuel by volume, so plan for bigger tanks or more frequent refills.

A standby generator should be serviced once a year or every 250 running hours, whichever comes first: oil and filters, coolant, battery, belts and hoses, plus a load test. In between, run it for about 30 minutes a month, ideally with some load on it, so problems show up before a power cut does.

Diesel stored for long periods can grow “diesel bug”, so check the tank and filters. Portable generators follow the maker’s schedule, usually an oil change every 50–100 hours. We offer generator servicing and maintenance.

You don’t plug it into a socket. Feeding a generator into your house wiring through a plug or socket sends power back down the line (back-feeding), which can injure ESB Networks crews, your neighbours or you, and can wreck the generator when mains power returns.

There are two safe ways. Run individual appliances from the generator’s own sockets using outdoor-rated extension leads, or have a registered electrician fit a changeover switch so the house runs from the generator while it’s fully isolated from the mains. ESB Networks’ guidance on standby generators sets out the rules.

Yes, if the generator will power your home or business wiring. A changeover switch, manual or automatic, disconnects you from the mains before the generator takes over, so you can’t back-feed the network. ESB Networks requires one for every standby generator, and one generator should never be shared across two properties.

By law, electrical work in your home must be done by a Safe Electric Registered Electrical Contractor, who will give you a completion certificate. With an automatic changeover switch and an auto-start generator, power comes back within seconds of a cut, which suits farms, businesses and anyone often away from home.

Never run a generator indoors or in a partly enclosed space, including your home, garage, shed, porch or lean-to, even with doors and windows open. Generators produce carbon monoxide, which you can’t see or smell and which can kill within minutes. Keep it outdoors, away from doors, windows and vents, and fit a carbon monoxide alarm.

Don’t run it in the rain without cover, touch it with wet hands, refuel it while it’s hot, overload it, or connect it to house wiring without a changeover switch. Stay clear of fallen wires and report them to ESB Networks on 1800 372 999.

We stock a wide range of new and used generators, from compact 10 kVA units to 5,000 kVA industrial sets, mainly diesel. New stock includes EPS/KOFO diesel generators and silent canopied sets, and our used range has included Perkins, Volvo, John Deere, Hyundai and Dorman generators.

Stock moves quickly, so browse all generators or call 05394 21599 to check what’s available today.

Both. We sell new generators and used generators, mostly diesel generators, and we also hire out generators for emergency use. A quality used generator can save a lot on a large unit, while new suits buyers who want the latest spec and a full manufacturer warranty. Tell us what you need and we’ll find the right fit.

Yes. Generators Ireland operates from industrial units at Gorey Business Park, Ramstown, Gorey, Co. Wexford, where you can see generators in person. It’s best to call ahead on 05394 21599 to arrange a viewing, so the units you’re interested in are ready to look at. Office hours are 9am to 6pm.

Yes. New generators come with a standard one-year manufacturer warranty, and our second-hand generators come with a service and repair warranty. Ask us for the exact terms on any unit before you buy.

It depends on size, fuel, new or used, and installation. As a rough guide, small portable petrol generators start from a few hundred euro, while a home standby diesel generator with an automatic changeover switch usually runs to several thousand euro once it’s installed. Large commercial and industrial sets are priced individually.

A used generator can cut the cost of a bigger unit considerably, and hire avoids the upfront cost altogether. Tell us what you need to power and we’ll send you a quote.

Yes. We hire out generators for emergency use, from small units to large diesel generators, for power cuts, storms, breakdowns and planned shutdowns. Tell us what you need to power, where the generator will go and how long you’ll need it, and we’ll match the right size.

For urgent help, call 05394 21599 or our mobile on 087 256 2919, or see our emergency response service.