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Picking a Generator for Your Portable Construction Office

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Finding the best generators for your construction portable office rental takes more than just hooking one up and turning it on. Selecting a generator that is not sized correctly can lead to annoying circuit breaker trips, faulty equipment, and undue wear and tear on the generator itself. If you choose an undersized generator, you may have no trouble turning on the lights or charging your cell phone, but you’ll likely trip the generator circuit breaker if you try to turn on the heater or air conditioner. If you choose a generator that is too oversized, it can damage the generator. Running generators at low loads for long periods leads to increased maintenance costs.

We’re often asked what portable office generators are best for construction sites. In this post, you’ll learn how to figure out your wattage and what to look for when choosing from the different generator options.

Calculating Power for Your Portable Office Generator

When considering generator power, you need to know the wattage of all the equipment used inside your portable office, including HVAC units, lighting, computers, printers, TVs and coffee machines. Most devices will list either their total wattage or their amperage and voltage. Add up the total wattage of each product that the generator will power to figure out how much generator power you need.

If you only know the amps and volts of your equipment, multiply amps by volts to get the wattage.

When you rent one of our portable offices, we recommend a generator wattage size for the office you select, if requested. This will help narrow down your generator choices.

A portable office generator provides emergency power.
Choosing the best generator for your portable office rental doesn’t need to be a challenge. Being aware of your total wattage for the devices you’ll be using goes a long way in picking the right generator to power your construction site.

Choosing the Best Portable Office Generator

Your construction project will dictate which portable office rental you’ll need, which will, in turn, help to determine the size of the generator. For our offices, you may use a portable generator between 3 kW and 10 kW or a trailer-mounted generator between 10 kW and 30 kW, depending on the office and your needs.

You shouldn’t operate portable office generators for more than 30 minutes at maximum power. However, if you plan on using it as a primary power source for your construction site, the generator should be a size that can operate within 70-80% capacity, which will help with overall performance and allows for any further power requirements.

Portable Office Generator Checklist

When choosing a generator for your construction portable office rental, there are several factors you should consider to ensure you select the right one for your needs. Here are some key points to keep in mind:


Start by assessing the power requirements of your construction portable office. Calculate the total wattage needed to run all the electrical equipment, including lights, computers, HVAC systems, and other devices. This information will help you determine the generator size and capacity you require.

Size and Capacity

Portable office generators come in various sizes and capacities, typically measured in watts. Look for a generator that can handle your total power requirements with additional capacity for future needs or power spikes. It’s better to choose a generator that slightly exceeds your requirements than one that falls short.


You can power portable generators with different fuel types, such as gasoline, diesel, natural gas, propane, and solar. Consider the availability of fuel sources on your construction site and choose a generator that aligns with what is easily accessible and convenient for you.


Evaluate the generator’s run time on a full tank of fuel. Construction projects often require generators to run for extended periods, so you’ll want a model that offers sufficient run-time without constant refueling. Additionally, look for portable office generators with fuel-efficient features to minimize operating costs.


Construction sites can be noisy environments, but it’s still important to consider the noise the generator produces. Look for generators designed to operate quietly, especially if your construction portable office is near working areas or residential neighborhoods.


Since you’ll be using the generator for a portable office, consider its portability and ease of transportation. Look for models with sturdy handles, wheels, or trailers for easy maneuverability on the site.


Construction sites can be demanding environments, so choose a generator built to withstand the rigors of such conditions. Look for generators with durable construction, weatherproof features, and solid warranties to ensure reliability and longevity.

Safety Features

Portable office generators should have safety features such as circuit breakers, grounding mechanisms, and low oil shutoffs to protect against electrical hazards and prevent damage to the generator itself.


Consider your budget constraints and balance them with your power requirements. While it’s important not to compromise on quality and reliability, portable office generators are available in various price ranges. Compare prices and features to find the best fit for your budget.

Reviews and Recommendations

Before making a final decision, read reviews and seek recommendations from professionals in the construction industry. Their insights and experiences can guide you in selecting the right generator for your construction portable office.

A portable generator is refueled with gasoline.
You can power generators with different fuels, like gasoline, diesel, natural gas, propane and even solar.

Portable Office Generator Top Brands

When choosing a generator for a shipping container, several reliable brands are known for their quality and durability.

When selecting a generator, consider power output, fuel efficiency, noise levels, and portability to ensure it meets your needs. Additionally, it’s always a good idea to read reviews and compare specifications to find the best generator for your shipping container.

Here are six leading generator brands to consider:


Champion is a brand that offers a range of affordable and reliable generators for a portable office. They are known for their rugged designs and excellent performance, making them suitable for shipping container applications.


With their robust construction and advanced features, DeWalt portable office generators deliver consistent and clean power output, making them ideal for various applications, including portable office job sites and emergency backup. DeWalt’s reputation for quality ensures long-lasting performance and peace of mind.


Generac is another reputable brand for producing various office generators, including portable and standby models. They offer reliable power solutions with various power output options for different container needs.


Honda is a renowned brand that produces reliable portable office generators known for their fuel efficiency and quiet operation. Their generators are often compact and lightweight, making them suitable for shipping container applications.


Westinghouse generators are reasonably priced and dependable. They offer a range of portable generators suitable for various applications, including powering shipping containers.


Yamaha manufactures high-quality generators that are known for their durability and performance. They offer portable and inverter generators, providing stable power for sensitive electronics and equipment.

Construction Container Modifications

Southwest Mobile Storage is a reliable and innovative provider of construction container modifications. Our unwavering commitment to quality and customer satisfaction has earned us a stellar reputation in the industry. By harnessing the versatility of shipping containers, we offer a wide range of customized solutions for construction projects of all scales.

Our team of experienced professionals understands the unique needs and challenges of the construction industry. Whether it’s converting containers into on-site offices, storage units, or portable workshops, they have the expertise to deliver exceptional results. Our attention to detail ensures that every modification is tailored to meet our clients’ specific requirements and preferences.

Watch us modify a 20ft shipping container with electricity, HVAC, insulation and more! Or, watch this video and learn how to connect power to your mobile office.

Moreover, we place great emphasis on delivering outstanding customer service. We prioritize open communication, actively listening to our client’s needs, and providing personalized solutions. Our commitment to transparency and timely project delivery sets us apart from the competition, earning the trust and loyalty of our customers.

Contact us today for a free consultation on how to modify a shipping container for your construction needs.

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