What Size Generator to Run a House? Let’s Find Out!

Don't let power outages disrupt your life. Invest in a reliable generator. Knowing what size generator to run a house is key to keeping essential appliances and systems working. But how do you figure out the right size? Let us walk through it together, and with the help of this article, you will have a clear idea of what generator you need to keep your home powered, comfortable, and safe.

Why Generator Size Matters?

Choosing the right generator size for your home is essential for several reasons. First, it impacts performance and efficiency. If a generator is too small for your power needs, it will struggle to keep up, leading to overexertion, increased fuel consumption, and premature wear and tear. Overloading can damage both the generator and any connected appliances.

Conversely, an oversized generator can operate inefficiently, wasting energy and raising your operational costs. A generator that is too large may cause frequent charging cycles, which can shorten the battery's lifespan.

How Do You Determine the Correct Size Generator for Your Home?

What size generator do I need to run a house? Generators provide essential power during outages, but choosing the right size is crucial. Start by assessing your power needs and the devices you want to support, whether for your home or a construction site.

1. Assess Your Power Needs

This step ensures that the generator can handle the essential appliances and systems you rely on daily.

• Check wattage labels: Look for wattage information on the appliance’s label, usually found on the bottom or back.
• Consider variable settings: Be aware that devices may use different amounts of power based on their settings.
• Calculate missing wattage: If no wattage is indicated, you can determine it by using the formula: WATTS = VOLTS × AMPS. For example, if a device runs at 10 amps and 120 volts, it uses 1,200 watts (10 x 120).
• Refer to manuals: If wattage, amps, or volts aren’t available, consult the owner’s manual or the manufacturer’s website for details.

2. Calculate Your Total Power Requirements

Next, you will need to determine your total wattage needs, which includes both running and starting watts.

• Identify running watts: These are the watts needed to keep your devices operating continuously.
• Identify starting watts: This refers to the additional power required for the initial surge when starting motor-driven appliances.

3. Select the Appropriate Generator Size

Once you have a clear understanding of your wattage needs, it is time to choose the right generator size.

• Combine your wattage needs: Add up the total running watts of all devices you plan to use simultaneously. Then, include the highest starting wattage from any of these devices.
• Account for generator capacity: Aim for a generator that can handle this total wattage without exceeding 100% of its capacity. The U.S. General Services Administration recommends sizing generators to about 110% of your calculated load, ideally running between 50% and 80% of their rated capacity.
• Understand generator ratings: Generators are often rated in kilowatts (kW) for actual power and kilovolt-amperes (kVA) for apparent power. Keep in mind that kW indicates usable power, helping you assess the generator’s actual output accurately.

Common Appliances and Their Power Consumption

Determining the right generator size for your needs can be tricky. The best approach is to calculate your wattage requirements using a wattage worksheet. Below, you’ll find typical wattage ranges for various common appliances and uses.

• 500 to 3,000 watts:This range is suitable for recreational equipment, power tools, small appliances, and lighting.
• 3,100 to 6,000 watts:Ideal for recreational activities, heating and cooling systems, as well as mid-sized appliances.
• 6,100 to 10,000 watts:This size is necessary for emergency power, larger heating and cooling units, and substantial appliances like water heaters.
• 10,100 Watts and above: Designed for comprehensive emergency power needs, capable of supporting entire homes.

Generator Size Recommendations Based on Home Size

Each home has its own unique power requirements, ranging from essential appliances to a full suite of electrical devices. Generally speaking, most households will find that a generator between 5,000W and 7,000W is sufficient to cover their needs during a power outage. However, the exact wattage you will need will ultimately depend on the specific electrical devices you plan to power.

Factors to Consider When Choosing a Generator

Choosing the right generator isn’t just about wattage. Several factors will influence your decision, including wattage, fuel type, physical size, type, noise levels, and cost.

1. Wattage

For reference, here’s a breakdown of generator sizes and their typical applications:

• 1 kW to 10 kW:Ideal for backup power in smaller homes, this range can support essential appliances. For instance, a portable 5 kW generator can run a refrigerator, four lights, and a fan. However, for big-sized homes, aiming for at least 10 kW is advisable. These smaller generators often use natural gas, propane, or diesel.
• 10 kW to 50 kW:This size range is suitable for homeowners needing to power multiple appliances at once. If you want to run energy-intensive devices like HVAC systems and washing machines simultaneously, consider a propane, diesel, or natural gas generator within this range.
• 50 kW to 100 kW:Generally diesel-powered, these generators are excellent for backup power in commercial settings like offices and restaurants.
• 100 kW to 200 kW:These units can support larger operations such as industrial sites or extensive office spaces, powering multiple computers, lights, and HVAC systems. They can run on both diesel and gas.
• 200 kW to 300+ kW:For continuous power needs, industrial generators in this range are ideal. They typically use diesel or gas and can supply energy for large industries and high-rise buildings equipped with elevators and escalators.

2. Type of Fuel

When selecting a generator, the type of fuel it uses is a crucial consideration, as each fuel source offers distinct advantages and drawbacks. Knowing these differences can help you make the right choice. Here’s a breakdown of common fuel types:

• Gasoline: It is readily available and often less expensive upfront. However, it has a shorter shelf life and can be less efficient than other fuels.
• Natural gas: It is convenient for those with existing gas lines and generally cleaner-burning. However, its availability can be an issue during emergencies if gas lines are disrupted.
• Diesel: It offers better fuel efficiency and longevity, making it cost-effective over time. However, it typically has a higher initial cost and can be harder to find in emergencies.
• Propane: It performs well in cold weather and can be stored indefinitely, making it reliable during outages. However, it tends to consume fuel more quickly than diesel, which could lead to higher operational costs.

3. Physical Size

When choosing a generator, its physical size is a vital factor to consider, as it impacts portability, installation, and the space required for storage. Generators typically fall into two main categories: portable and standby. Here’s a closer look at each type:

Portable generators:

• These units are designed for easy transport, making them perfect for outdoor activities like camping or for temporary power needs at home.
• Smaller models can easily fit in a garage or be taken on trips, providing convenience without taking up much space.
• Some portable generators come equipped with wheels, allowing them to be towed behind a vehicle, ideal for construction sites or events where mobility is key.

Standby generators:

• Unlike portable models, standby generators are installed in a fixed location.
• They provide reliable backup power for larger structures, such as homes, construction sites, and critical facilities like hospitals, ensuring consistent electricity during outages.

4. Type

From portable options to more permanent installations, here’s a breakdown of the main categories:

• Inverter generator: These generators utilize advanced technology to produce clean, stable energy. They are typically quieter, more fuel-efficient, and ideal for charging sensitive electronics like laptops and smartphones.
• Portable generator: Compact and versatile, portable generators are great for less demanding tasks, such as charging devices on a camping trip or powering small tools at home. However, they may not have the capacity to run larger appliances or an entire house.
• Standby generator: Designed for permanent installation, these larger generators can power an entire home or commercial building during outages. They often feature automatic startup capabilities to ensure continuous power supply, but they do require a larger investment.
• Towable diesel generator: These generators are equipped with wheels for easy transport and can be hitched to a vehicle. Ideal for construction sites or outdoor events, they provide a robust power solution while remaining mobile.

5. Noise Level

When selecting a generator, noise level is an important consideration, especially depending on your intended use. Generators can produce significant sound, so understanding how loud your unit will be is crucial. Here are some points to keep in mind:

• Size matters: Generally, larger generators are louder, while smaller units, especially inverter generators, are designed to operate more quietly.
• Usage environment: If you are using the generator on a construction site, noise may not be a significant concern. However, for outdoor festivals or in residential areas with noise ordinances, a quieter model is essential.
• Noise reduction features: Many manufacturers offer generators with built-in noise-reduction technology. This can help lower the decibel level significantly, or you can consider investing in a separate generator silencer.

6. Cost

When choosing a generator, several cost factors come into play. The upfront price varies by size and wattage, with larger, higher-capacity generators typically costing more. The Anker SOLIX F2000 Solar Generator + 3x 200W Solar Panel is an excellent choice if you are looking for a cost-effective, eco-friendly alternative to traditional fuel-powered generators. With a capacity of 2048Wh, it provides enough power to run essential appliances like refrigerators, lights, and even a small heater or air conditioner. The 3x 200W Solar Panels allow for efficient recharging, making it ideal for homes in sunny regions. The best part? No fuel costs or emissions—just clean, renewable energy.

Also, the Anker SOLIX F2000 Solar Generator + 2x 400W Solar Panel allows you to power up to 12 devices simultaneously. The two 400W solar panels are designed for faster charging, with IP67-rated waterproof protection. This system is perfect for backup power in homes, RVs, or outdoor use, making it ideal for off-grid applications with efficient, clean energy. The setup is durable, portable, and provides a long lifespan of up to 10 years thanks to InfiniPower™ technology.

 

Conclusion

Determining what size generator to run a house depends on your home's specific power needs and the appliances you want to keep running during a power outage. By calculating your household’s wattage, considering the size of your home, and factoring in costs, you can make an informed decision that suits your lifestyle.

FAQs

What is the difference between starting watts and running watts?

Starting watts refer to the extra power required for a brief moment, typically two to three seconds, to kickstart motor-driven appliances like refrigerators or circular saws. In contrast, running watts (or rated watts) represent the continuous energy needed to keep these devices operating once they are up and running.

Can a portable generator power an entire house?

A portable generator rated between 5,000 and 8,000 watts can typically power a standard home, covering essential appliances like the air conditioner, refrigerator, sump pump, laptop, TV, and lights.

What size generator can run a full house with AC?

To run a full house with air conditioning, the generator size depends on your AC unit's capacity. For a 3-ton (30-Amp, 36,000 BTUs) AC, you'll need at least a 14 kW generator. For a 4-ton (40-Amp, 48,000 BTUs) unit, aim for a minimum of 17 kW. If you have a 5-ton (50-Amp, 60,000 BTUs) air conditioner, you will require at least a 20 kW generator to ensure reliable power.

What size generator to run a 1500 sq ft house?

To power a 1,500 sq ft house, a generator in the range of 10,000 to 14,000 watts is typically sufficient. This size can comfortably support the entire home, ensuring all appliances and systems can operate simultaneously without the risk of overloading. Standby generators generally vary from 8,000 to 20,000 watts, but for your needs, the 10,000 to 14,000 watt range is ideal.