How Many Watts Will My Generator Need?

Properly Size Your Solar Generator System To Perfectly Meets Your Power Needs.

There’s nothing worse than being caught short -- whether it’s short of money or short of power – especially when renewable solar & wind energy power is free.

What size generator do I need?

To ensure your generator system is the correct size for your needs, calculate the total electrical load and daily energy consumption of the devices you want to power. Then, size your generator’s watt and watt-hour capacity accordingly.

Below is a step-by-step guide to help you determine:

• What size generator do I need for my house?
• How much wattage your generator will need for your devices to function.
• How many watt-hours of energy consumption your system needs to keep your devices running for the desired period.
• How many renewable energy sources, like solar panels and wind turbines, you’ll need to properly “fuel” your system.

Identify Your Purpose

Your purpose could be ensuring you have a reliable portable back-up generator that can run a few of your home’s critical devices during a power outage or, at the other end of the spectrum, your purpose could be to seamlessly run your entire home’s energy needs day and night. For instance, what size generator to run a house depends on the energy requirements of your home.

We at Nature’s Generator sell generator systems of many different sizes, from our portable 1800-Watt or 3600-Watt units on up through generators like our whole-home 7200-Watt Powerhouse systems that are capable of powering an entire house. We also have lightweight portable solar panels up to our larger rooftop solar panel systems. Not sure what size generator do I need? Give us a call, we can help you determine what you will need to power a system for your purpose.

Watts Power a Device While Watt-hours is Energy Consumed Over Period of Time

A key thing users must understand when selecting a generator is:

• Watts measure the power it takes for a device to function.
• Watt-hours measure the energy consumed over a certain period of time. 

Keep in mind that you must first purchase a properly sized generator that has enough power to run the devices you want to run. Generators are tools. The correct tool is important. No one would use a Honda Civic to pull a large fifth-wheel trailer -- it’s the same principle with generators – you need a generator with enough wattage to power what you want to power.

Review the below wattage estimates for commonly used electrical items to get a sense of what different electrical devices require to function.

Create a List of the Devices You will Want Your Generator to Power

Note that the actual wattage required by your appliances may be different from the common estimates listed above -- so to be safe -- use the exact wattage required by your electrical items to calculate the power your system will need. You can locate the watts each of your electrical devices require to function on the product’s nameplate or in its user manual.

The wattage listed on items like hot plates, toasters, or space heaters may have low, medium, or high settings and their information plaque will usually list the appliance’s maximum running watts. To be safe, use this maximum running watts to calculate your overall wattage needs.

TIP: On refrigerators there is usually a plaque giving the “average running wattage” or “average running amperes” inside the refrigerator on the left wall.

How to Determine Watts If Your Appliance Only Gives the Amps Information

If your device has its power requirements defined in Amps (Amperes) instead of Watts, you can convert Amps to Watts using this formula: Volts x Amps = Watts. Most appliances in the United States use 120 volts, however, larger appliances (such as clothes dryers and electric cooktops) require 240 volts. Meaning that when using the formula, if the voltage is 120 then take 120 volts X Amps = Watts or if the voltage is 240 then take 240 volts x Amps = Watts.

IMPORTANT:  Difference Between “Average Running Wattage” & “Starting Surge Wattage”

In the list of “typical wattage estimates” above you can observe the parenthetical statement “Requires startup surge wattage to start.”  This means that to determine the wattage power that your generator must provide, you need to determine both the average running wattage and the startup surge wattage of any appliances with a motor.

While the average running wattage represents the power needed to keep an appliance running, the startup surge wattage is the power needed to start electric devices with a motor. Appliances like refrigerators, washing machines, clothes dryers, etc. that have a motor that will require 2 to 4 times the average running wattage for a short period (a few seconds) when starting up. Your generator system must be capable of reliably delivering not only the average running wattage but also the startup surge wattage that your items require.

Think about a refrigerator that will cycle on and off multiple times a day to keep the refrigerator at the set temperature to preserve food. Each time the refrigerator comes on, it requires a surge of startup wattage. The more a refrigerator door is open and shut during a day, the more often the refrigerator motor will have to cycle on to regulate its internal temperature — meaning it’s important to calculate and add in the startup surge wattage of high-use appliances when determining what size generator do I need for your system’s wattage needs.

How to calculate Startup Surge Wattage

A general rule of thumb to determine startup surge wattage is to multiply the average running wattage by 3 -- average running wattage x 3 = startup surge wattage -- however, if you want to be even more confident your generator has the power to cover your appliance’s startup surge wattage requirements, then multiply your appliance’s average running wattage by 4.

After you have determined which of your appliances need startup surge wattage, then select the device which requires the highest amount of startup surge wattage.  

The reason for identifying your appliance that requires the highest amount of startup surge wattage is that generally you only add the highest startup surge wattage required  to your calculations for how much wattage your generator will need. This is because, unlike an appliance’s average running wattage (which is continuously needed while the appliance is running) the startup surge wattage will only be required for the first few seconds when a motor-driven appliance is starting up. The thinking is that it’s unlikely that more than one appliance will be turning on at the exact same time and because of this most electricians feel that it’s safe to select the appliance with the highest startup surge wattage requirement and use that number to cover all your appliances’ startup surge wattage requirements.

There is a “HOWEVER” and here it is: If you know you will be turning on certain equipment that requires startup surge wattage many, many times per day, it will increase the likelihood that multiple devices will be starting up at the same time. In this case, add the startup surge wattage of each of these high-use devices or appliances to your wattage requirements to ensure your generator has the wattage to handle the electrical load of two or three such high use items coming on simultaneously.

Note that devices like light bulbs that don’t have a motor, won’t need an extra boost of power when they turn on. This means for things like light bulbs, toasters, radios, waffle irons, etc. that you do not need to calculate startup surge wattage, instead you will only need to add the device’s wattage to the total wattage your generator will need to provide.

Watts = Power Needed to Function & Watt-hours = Energy Used Over Period of Time

Remember, while watts measure power needed for a device to function, Watt-hours calculate the total energy consumed by electrical devices over a set period of time. This is important because you first need to select a generator that has enough wattage to power what you want your generator to power, but you also need to supply enough watt-hours of energy to keep your devices running for the period of time you require them to run. Understanding this is key to determining what size generator to run a house efficiently.

Add all of your electrical devices wattage requirements together including the highest startup surge wattage requirement(s). This will give you the watts that your generator will need to supply to allow your electrical devices to function. (Note that most electricians would recommend at least an additional 25% buffer to this number.)

Then ensure your system can support the watt-hour requirements to keep your devices running for period of time you desire. To calculate watt-hours, take the wattage of each individual device and determine how many hours you use that device each day, then multiply the two numbers. The formula is: Watts x Hours = Watt-hours of energy consumption per day per device.

Now add the devices Watt-hours requirements together. This will give you your Watt-hour (energy consumption) required by your system to supply to run your devices for the period of time you need them to run. (Many electricians would recommend at least an additional 25% buffer to this number to be safe.)

It's also notable that many of Nature’s Generator systems are expandable allowing users to expand the Watt-hour capacity of their generator by adding Power Pods that can increase a system’s Watt-hour capacity.

Below are a few examples of Watt-hour calculations:

Portable Fan

In the heat of summer, you might have a portable fan that uses 120 watts of power and runs for 8 hours per day. That would be 120W x 8 hours = 960 watt-hours (Wh) daily of energy consumption.

Space Heater

Conversely, during chilly fall or winter days, you may have a space heater that draws 1000 watts running for 8 hours each day. 1000 Watts x 8 hours = 8000  Watt-hours (Wh) of energy consumption on each chilly day.

Outdoor Floodlight

Say you have a 60-watt floodlight outside for nighttime safety. If you have the light on from 6 PM to 6 AM each day/night, then using the formula 60 watts x 12 hours = 720 Watt-hours (720Wh) of daily energy consumption. (Note that with newer energy saving LED floodlights the wattage can be reduced from 60 watts to only 9 or 10.)

Refrigerator

For a refrigerator that will cycle on and off all day/night, a rule of thumb is to assume that it will be running about one third of the time or 8 hours during a 24-hour period. (But if your refrigerator is high use -- with the door opening and shutting often -- then increase this rule of thumb percentage.)  If you have a larger 1000-Watt refrigerator then using the formula 1000 Watts x 8 hours = 8000 Watt-hours (8,000Wh) of daily energy consumption for your refrigerator.

For Off-Grid Use How Much Surplus Energy Should be Stored?

If you are planning your system for an “off-the-power-grid” application, then you need to size your renewable energy system to run all the electrical items used on an average day plus calculate enough surplus energy generation to store for later use in your generator’s battery system. If you only consider the exact power consumption needed to run your items daily, then you are not considering the need to have extra energy stored to power the system when the sun’s down or the wind has stopping blowing. It is better to oversize your system for your power needs then to come up short if you are planning an off-grid system.

Ensure Your Energy Collection System Can Properly “Fuel” System

Beyond calculating how many watts your generator will need to allow your devices to function and how many Watt-hours you will need to keep the system running over a certain period of time, you also will need to consider the power that the renewable-energy system will need to collect. If you have the right-sized generator but are not supplying it with enough solar fuel to keep up with your daily power demands, then it may appear that the system doesn’t work, when in reality you just need to add more solar power collection capacity to “fuel” your system.

Think of it this way, you are planning a 500-mile trip, but you only put enough fuel in your vehicle to get 300 miles, when you reach 300 miles the vehicle will stop -- not because the vehicle doesn’t work anymore, but because it didn’t have enough fuel to reach your destination.

Solar and wind power are the free fuel in our renewable energy systems. You must ensure your system has enough power and battery storage capacity to meet your power needs as well as having enough solar/wind fuel generating capacity to run all the appliances you want to run and still have excess energy left to store for use when the sun goes down. It‘s critical that your system has enough renewable energy “fuel” to generate surplus energy to store to allow your system to continue to work after the sun has set when the system is working only on stored energy.

Your goal is to have a perfectly balanced system with enough power and energy supply to run your equipment as well as enough surplus energy left over to store which will keep your system running at night, or on rainy days, or during shorter winter days where less solar energy can be collected. Therefore, remember to calculate enough solar and/or wind power “fuel” generation to feed your system.

Just as you would not put 10 gallons of fuel into a vehicle to take a trip that requires 20 gallons, you cannot put only half the solar/wind energy collection capacity into your system and expect it to meet your home energy demands.

Steps For Calculating The Size of Your Renewable Energy Generator System

1. LIST ITEMS TO BE POWERED WITH THEIR REQUIRED RUNNING WATTAGE.

List of the electrical items you want your generator to power and determine their average running wattage requirement of each device

2. CALCULATE THE STARTUP SURGE WATTAGE REQUIREMENTS.

For appliances with electric motors, determine the startup surge wattage using the standard multiplier of 3 times the running wattage.  Using this formula Running wattage x 3 = Startup Surge Wattage would mean a 700-watt appliance motor will require 2100 watts to startup. As described above, select the appliance with the highest startup surge wattage requirement and use that number to cover all your appliances’ startup surge wattage needs, with the caveat that if you will use multiple high-use devices with startup surge wattage requirements (such as air conditioners or circular saws) that will be turned on and off many times per day, then also add in the startup wattage for each of these high-use items when calculating your generator’s overall wattage requirements. 

3. CALCULATE THE HOURS EACH DEVICE IS USED PER DAY (WATT-HOURS).

Calculate the amount of time each device will be used on an average day and then multiply the hours by the device’s watts and that will give you watt-hours for each device. Again, the formula is: Watts x Hours (used per day) = Watt-hours of energy consumption per day. Next:

• Add the watt-hours required by your devices together, (remembering to add the starting wattage requirements when figuring the watt-hours for high-use items with motors).
• Totaling the watt-hours each device will use on an average determines your system’s total electrical load per day.
• Most electricians will then add at least an extra 25% safety buffer to total electrical load, however if your system is off grid and you want to ensure that your system has enough energy supply and enough battery storage to keep your system powered for two or three days of stormy/overcast weather then you need to increase the buffer accordingly. Remember it’s better to have extra watt-hour power in reserve than to have your generator stop when you need it most.

4. ENSURE YOUR SYSTEM HAS ENOUGH ENERGY-GENERATING “SUPPLY” CAPACITY.

Once you have the total electrical load, it is important to ensure that your system’s collection capacity is large enough to supply the renewable energy “fuel” to power your system.

Your free renewable energy fuel supply comes from your solar panels and/or your wind turbines. You will need to have enough solar and wind generating power to meet the energy demands you’re asking the system to provide plus surplus to store “for a rainy day.” The system must be balanced with enough wattage power, enough battery storage capacity, and enough energy supply generation capacity so that  your system’s reserves will not be drained completely. Without the proper renewable energy fuel generation capacity (solar panels and/or wind turbines), the system will not be able to meet your energy demands.

Using your system after the sun goes down or before it comes up, means you must ensure you have adequate power reserves to do this. To be off grid, it’s important you design a system with sufficient energy-generating capacity and battery-storage capacity to allow your system to accomplish this without completely draining all your power reserves.

5. ENSURE ENOUGH BATTERY CAPACITY TO STORE SURPLUS ENERGY TO USE WHEN THE SUN IS NOT SHINING OR THE WIND IS NOT BLOWING.

Battery storage capacity is important, especially if you plan to run your system for a couple of hours before the sun comes up and more hours after the sun has gone down, then you need to make sure your renewable energy system is correctly sized to take this need into account.

You want your system to perform all the work it did during the daylight hours, but now it must do this only with stored energy. Your solar panels will not be able to generate more power until the sun comes up again, so you need to design your system, so that it has enough stored energy capacity to supply your after-dark electricity needs each day and still not completely drain the system’s stored energy.

This is where Nature’s Generator Power Pods really shine. Our Power Pods can expand the Watt-hour capacity of most of our generator systems.

If your system is designed correctly, there should always be enough Watt-hours of energy left “in reserve” to power up your system the next day and have a stored surplus energy to run your home after dark or during particularly stormy weather periods where solar panel energy collection capacity is greatly reduced.

6. SOLAR SYSTEM SET UP TIPS FOR PEAK SYSTEM PERFORMANCE.

Clean And Maintain Your Solar Panels For Optimal Performance

Solar panels can still work on cloudy and even rainy days; however, they will not be working at their peak performance levels. Panel efficiency will depend on the amount of cloud coverage. Consider that anything that blocks your solar panels from absorbing sunlight can reduce the panels’ power production. Things like snow, rain, fog, clouds, dust, dirt, bird droppings, leaves, twigs, or shade from trees or buildings can all adversely affect the panel’s photovoltaic (PV) cell’s ability to absorb sunlight causing the panels to underperform.

Just like looking through a dirty windshield can affect clear driving visibility, to get the most from your solar panel collection system you need to keep your panels clean so they can function at their highest capacity. Solar panels become dirty over time, to get the best performance users should make sure they keep their panels clean. In many areas, abundant natural rainfall keeps the panels clean, however, if you are in a particularly arid area or are surrounded by dusty farmland then more cleaning maintenance may be needed. Most experts feel that cleaning the panels an average of every six months will work -- but you want to adjust your maintenance for your particular situation.

If your panels are quite dirty, mix a little vinegar with water to clean the panels, then rinse them with clean water, and dry them with a soft, dry cloth to avoid water spotting. (Like washing a car, it’s probably best not to do this in the midday heat which can promote water spotting.) Additionally, do not use ammonia-based glass cleaners or harsh commercial soaps because they can leave a film and/or soapy buildup which can affect the solar panels’ ability to collect solar energy.

For Best Solar Collection Optimize Your Solar Panels’ Tilt Angle

Solar panels receive their greatest amount of energy and produce their maximum efficiency when oriented or tilted directly toward the sun. South-facing solar arrays can produce the most power. If solar panels are mounted flat on a flat roof, then the panels cannot achieve their ultimate performance because when the sunlight strikes flat panels, most of it is deflected because the sunlight is not penetrating the panels perpendicularly. When you tilt or pitch the solar panels toward the sun, then they perform better because it ensures maximum solar energy absorption. Panels on a flat roof are usually tilted up at a 10-to-40-degree angle toward the sun for the best sun collection for the geographical area which they are located.

For Best Solar Panel Tilt, Know Your Area’s Seasonal Changes

The sun’s position in the sky changes seasonally as well as daily. As the Earth rotates around the sun over a span of one year, the sun is in different positions during different seasons, in much the same way as the sun is in different positions during each day.

There are times of the day in the solar industry that are known as “peak sun” hours which are usually around 10 AM to 4PM. These tend to be the prime or optimum hours for the solar energy collection and therefore for electricity generation. When planning your solar energy system make sure your panels will receive ample peak sun hours.

The main tilt-angle positions for seasonal changes are the mean, the winter, or the summer position. Basically, if it is your goal to generate the maximum amount of solar energy year-round, you should use the mean position. This angle receives sunlight throughout the year and is positioned at 10 degrees from horizontal and facing due South. However, if the goal is to increase solar generation capacity during winter, then opt for the winter tilt as it accounts for the sun’s lower position in the sky during that season. This winter position angle-tilt is 40 degrees from horizontal and facing due South. Since the summer days are longer with better solar collection capability,  the summer position is likely the least used position. As a basic rule of thumb, the ideal degree of tilt of should be approximately equal to the latitude of your geographical location facing south.

In the continental U.S., panels are generally tilted toward the south for best collection. Therefore, if your home has a sloped roof, the panels should be installed on the most south-most facing side of the roof for best performance. Of course, always avoid areas that are shaded or could collect leaf debris for best solar collection.

Nature’s Generator Has Many Renewable Energy Systems To Meet Different Needs

Nature’s generator has various systems to meet many different needs. All of Nature’s Generator renewable energy systems can be recharged by our state-of-the-art solar panels or wind turbines or both simultaneously. Harnessing the free abundant energy of the sun and wind has never been so easy.

Additionally, because Nature’s Generator’s systems are expandable, it is not difficult to achieve a balanced system for your home’s renewable energy needs. Taking a little time up front to calculate what you want your system to power (wattage) and how long you will need it to run (Watt-hours) will be worthwhile and will enable you to keep your home’s power well-supplied and running smoothly.

PORTABLE BACKUP GENERATOR SYSTEMS

Power on the go. The Nature’s Generator Lithium 1800 weighing in at only 40 lbs. is the perfect portable system to power an on-the-go lifestyle. Whether you are going camping, boating, tailgating, or need electricity for a farmer’s market booth, or need to power tools on a jobsite where there’s no electricity supply -- this little work horse is compact and portable. Additionally, it can serve as backup power in your home in the case of emergencies.

The SLA Standard 1800-Watt or Elite 3600-Watt systems are portable and can provide power on the go or can serve as an emergency backup generator for your home. These systems are expandable, with more Watt-hours of energy consumption provide with each additional Power Pod purchased, allowing them to provide ample backup power for households in areas hit by frequent power outages. They are a highly affordable solution for preparing your home for the inevitable outage or disaster.

WHOLE-HOME GENERATOR SYSTEMS

The Powerhouse does just what it says with 7200-watt maximum output with an impressive 4800Wh of power, it is ready to power a house. The Powerhouse systems can be expanded if your household requires more watt-hour capacity. Individual Power Pods designed for the Powerhouse can be added to expand the Powerhouse system’s watt-hour capacity. One Power Pod will double the watt-hour capacity to 9600Wh, two Power Pods will increase the watt-hours to 14,400Wh and so on. But remember if you increase your Watt-hour storage capacity, also ensure your power generation capacity (solar panels and wind turbines) is sufficient to supply and recharge your generator’s battery system

The Powerhouse systems can give you a tremendous bang for your electricity dollar, harnessing the free abundant energy of the sun and wind is a win for your wallet and a win for the environment.

SOLAR PANELS

Nature’s Generator is proud of our state-of-the-art monocrystalline solar panels, available for the portable systems in 100W portable panels and in the home-based systems in 410W home solar panels. They have a high efficiency rating, impressive power output, and the capacity to generate energy even in lower-light conditions before and after the more prime peak solar collecting hours of 10 AM to 4PM. Now, we also offer new convenient, portable, lightweight folding solar panels! See our website for more information.

WIND TURBINES

Nature’s Generator sleek functional wind turbine can allow continued recharging of your clean renewable energy system even after the sun has gone down. The wind turbines are not quite as fast for recharging the renewable energy generator systems as are the solar panels, however, they supply another way to charge most Nature’s Generators. Our company was the first renewable energy solar power company to offer simultaneous solar panel and wind turbine recharging – truly a wind-win!

POWER TRANSFER SWITCHES

Nature’s Generator manual and automatic power transfer switches are home electrical system integration units that allow for either manual or automatic power transfer of certain crucial circuits (or even, with are larger systems, all of your home’s circuits) in an emergency power outage situation. Basically, when grid power goes down your home’s electrical power can be transferred either manually by flipping a switch with the manual units or automatically with the automatic transfer kits. These transfer switches allow for almost seamless uninterrupted home power.

Great news! The solar tax credit is boosted to 30% – a reward for making the right choice for the planet and your wallet! Your guide to the federal solar tax credit.

Please visit our website to see each of the different affordable Nature’s Generator Products available and select the one best for your application and your power needs.

We hope this guide has helped you feel confident in taking the next steps to harness the FREE and abundant energy of the sun and wind. Nature’s Generator