Deep Energy Retrofits May Never Pay For Themselves
Thereâs something of an 80/20 rule when it comes to net zero homes. That is, you can spend relatively less money to get most of the way toward a net zero house, but the final steps to get to 100% energy self-sufficiency can get very expensive.
How Many Solar Panels Do You Need For Specific System Sizes
In our long example at the beginning of this piece, we determined that an 8 kW system would probably cover the average energy use for an American household if you live in an area with a production ratio of 1.6, which might be a realistic number for homes in most parts of California. Lets extend that a little further, and look at a few more examples. In the table below, weve compiled some solar panel estimates for common system sizes seen on the EnergySage Marketplace. Again, the big caveat here is that were using 1.6 as the production ratio of choice. For California shoppers, this might actually be realistic, but for folks in the Northeast or areas with less sun, these estimates might be a bit high on the production end and low on the number of panels needed.
How many solar panels do I need for my house? System size comparison
Few Things About Solar Panel Output Efficiency
Solar panel type and quality make a significant difference in terms of solar output and efficiency. Not all solar panels are the same.
For instance, monocrystalline photovoltaic solar panels are known to be the most efficient solar panels on the market, but also the most expensive.
Their two main advantages over the other types of solar panels such as polycrystalline or thin film panels is that 1) they absorb more sunlight than conventional cells and their output efficiency is not affected that much by temperature and 2) they occupy less space. These are an ideal option if you do not have enough roof space for standard panels.
On the other hand, polycrystalline panels are cheaper, they are less efficient and therefore occupy more space, but offer a better return on investment than monocrystalline panels.
Because of these wide differences in quality and efficiency, its up to you to decide which solar panels are right for your home.
The main takeaway is that, the more efficient the panels are, the more power they can produce, and the fewer photovoltaic panels you will need on your roof to get the same energy output as you would get with polycrystalline or thin film solar panels.
Overall, if money is not an issue, monocrystalline panels are the best option.
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What Is The Effect Of Solar Panel Size
If you have a small or unusually shaped roof, solar panel size and numbers are important considerations. With a large usable roof area, perhaps you can sacrifice some efficiency and buy more larger panels to get to your target energy output. But if your usable roof area is limited, or if its partially shaded, being able to use fewer smaller high efficiency panels may be the best way to make the most possible power over the long term, ultimately saving you more money.
Lets Say That Youve Decided Not Only To Go Solar But You Want To Go All
If youâve used our solar calculator or looked at the map of solar homes around you, youâll know that going solar is pretty easy and increasingly common. As the price continues to drop, it becomes affordable for more people. But what if you want to go completely solar? What if you donât want to use any fossil fuels at all in your home?
Yes, itâs possible for solar panels to supply all of the electricity your home needs. The first step is to maximize your energy efficiency with insulation, air sealing, and efficient appliances. Then, move off fossil fuel heating to electric heat pumps, and replace gas cooking and water heating with electric. Once youâve done that, a correctly sized photovoltaic system can be used to power everything in your home. But does it make sense?
This guide will explain how you can go completely solar in your home. But before we launch into it, letâs clarify what it really means when we talk about making your house completely solar.
- Want to generate all of your current electricity usage with solar, but leave some appliances, like your stove and furnace, using fossil fuels?
- Or do you want to move 100% of your home energy use to solar? This is called net zero.
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What Is An Off
An off-grid solar system is a complete package that contains everything you need to generate your own energy. These systems are suitable for homes, holiday homes, offices and larger buildings that want energy independence and help create green energy.
An off-grid solar system will include:
- Solar panels and mounting kits for roof or ground mounting.
- Solar power inverter to turn DC Solar current into AC mains current.
- DC to AC inverter for creating the power grid.
- Maintenance free batteries for efficient energy storage.
- CCGX monitoring panel so you can always see whats going on
- Autostart generator for emergency backup.
- 4G router to keep everything talking and online.
- Cables, fittings and fixings to put it all together.
Our off-grid solar systems can also include design and specification services and full fitting too!
Sunstore off-grid solar systems can supply enough energy for an average three bedroom house with family. They can also be scaled down for holiday homes and smaller properties if necessary. We can help you specify your own system or build one for you according to your needs.
How Many Hours Of Sunlight Does Your Home Receive
After determining your households monthly energy consumption, youll also want to figure out how many hours of peak sunlight your home can expect to receive.
Now, we understand that this number varies day-to-day, especially in Massachusetts, but making an educated estimate and then using the equation outlined below will allow you to determine a rough idea of the power required before consulting a professional solar installation company.
As a SunPower Master Dealer, well use their comprehensive, yet straightforward equation to determine how many watts of power your home would need per day to run off solar power.
Multiply your hourly usage by 1,000 to convert your hourly power generation to watts. Divide your average hourly wattage requirement by the number of daily peak sunlight hours for your area. This gives you the amount of energy your panels need to produce every hour. So the average U.S. home in an area that gets five peak sunlight hours per day would need 6,000 watts.
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Switch Your Gas Clothes Dryer For Electric Or A Clothesline
Most people choose natural gas clothes dryers, because standard electric clothes dryers that use electric resistance to provide the drying heat are inefficient and expensive to operate.
In addition, most clothes dryers are vented, meaning that they take conditioned air from your home, heat it up, blow it into the drying chamber, and then vent it outside. Because it is taking your conditioned indoor air and blowing it outside, your clothes dryer is making your HVAC system work harder.
A more efficient option is a ventless condensing dryer. Condenser dryers use your indoor air, heat it in a heat exchanger, circulate it in the drum to absorb moisture from the wet clothes, then send it to a second loop in the heat exchanger where the air is cooled. Cooling the air causes water to condense out, which is collected and sent to a drain. The same air is then recirculated in the drum, and the process is repeated until the clothes are dry.
Another type of efficient electric dryer uses a heat pump to generate heat instead of an electric coil. Heat pump dryers are also ventless, and even more efficient than condensor dryers.
Both heat pump and condensor clothes dryers are energy efficient electric alternatives to natural gas. Downsides: fewer products on the market, and a 50% to 100% higher price tag.
The best option of all? Use a clothesline. Itâs free, uses zero energy, is more gentle on your clothes, and your clothes will smell better.
How Much Does A Solar Panel Cost
Prices have been coming down steadily over the years. The total cost will depend on how many kilowatts of power your array will generate. According to consumer reports, after solar tax credits are accounted for, the cost for a solar panel system on an average-sized house in the U.S. in 2021 ranges from $11,000 to $15,000.
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How Many Solar Panels Do You Need For A 2000 Sq Ft Home
Estimating the number of panels based on home area is an indirect approach, since you must assume the kWh consumption. Some homes have more efficient appliances, and habits also influence electricity usage. However, average values can be calculated from official data:
- The US Energy Information Administration estimated that the average home uses 867 kWh monthly
- The US Census Bureau determined that single-family homes have an average area of 2467 square feet
- When dividing these values, you obtain 0.35 kWh per square foot
Assuming 0.35 kWh for a 2,000 sq. ft. home, the estimated electricity consumption is 700 kWh. At this point, you can use the calculation procedure described in the previous section. Considering 6 peak sun hours per day and 300-watt panels, you need 16 to produce 700 kWh each month.
If you have limited roof space, the best recommendation is installing the most efficient solar panels available. This will maximize the watts installed per square foot, compensating the area limitation. Finding out how efficient solar panels are is simple: you must only divide their individual wattage and area. The panels with the most watts per square foot have the highest efficiency.
What About A Battery
A storage battery will capture the unused solar power generated during the day, for use at night and on low-sunlight days. Installations that include batteries are increasingly popular. See our case study of the first Australian home to install a Tesla PowerWall battery.
But for most homes, we think a battery doesn’t make economic sense yet. Batteries are still relatively expensive and the payback time will often be longer than the warranty period of the battery. However, it’s likely that battery technology and prices, together with future changes in how the electricity market works, will make batteries a good option for most homes within the next few years.
And remember: for most grid-connected systems, having a battery doesn’t necessarily protect you in the event of a blackout. You may still lose all power to your home, despite having solar panels producing power and a charged battery ready and waiting. This is because grid-connected systems have what’s known as “anti-islanding protection”. During a blackout, the grid and any engineers working on the lines must be protected from “islands” of electricity generation pumping power unexpectedly into the lines.
For most solar PV systems, the simplest way to provide anti-islanding protection is to shut down entirely. So, when it senses a grid blackout, your solar PV system shuts down and you have no household power at all.
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Solar Panels: How Many Solar Panels Do You Need To Run An Off
Ok, I hope I didnt lose you there but dont worry, we are almost home. Now we can estimate how many solar panels we need to maintain our system.
Lets say you have a 100-watt panel. You want to take that number and multiply it by the number of direct sunlight hours you have in a day. So lets say you average about 6 hours of direct sun a day, that one panel can produce 600 watts a day.
Panel watts x hours of sun = Daily Output
Next, take your daily wattage needs, in the case above 9600, and divide it by the daily panel output.
Daily Need divided by Daily Output = Number of Panels
So in the case above, to achieve my 9600 watts a day, I would need sixteen 100 watt panels. Now, of course, this will depend on the wattage of your panels, but you should be getting a better idea of what you need to power your setup.
For the 9600 watt system, I need sixteen 100-watt panels and four 200-AH batteries.
Remember these are baseline figures to help with your estimation in the real-world, these are only numbers and just like all areas of preparedness you need to compensate for failure points. Its better to go a little bigger and overcompensate, becuase when it comes to off-grid power there are hundreds of factors that we cant account for that are going to popup at some point down the road. If a ten-day storm comes through and you lose the sun, you need to have a backup plan!
Solar Panels For A 1500 Square Foot House
The average home in the United States is roughly 1500 square feet. With a home of this size, the typical electric bill comes in around $100 month. In order to cover the electricity for this home, you would need an estimated 15-18 solar panels.
For example, a typical fridge may be rated for 250 watts and runs for 4 hours a day. 250 watts X 4 = 1000W. A 1k watt is equal to 1 kWh of energy in a day.
This, of course, is a general estimate and eclectic usage, sunlight hours, location, and the type of panels can change this amount.
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How Much Roof Space Is Needed For Solar Panels
The average solar installation will require between 335 and 405 square feet of roof space. To find out how much roof space your solar system needs, just multiply the number of panels you need by 17.55 square feet, which is the area of most residential solar panels sold today.
If you have limited roof space, you may need to get high-efficiency panels, or panels with a higher power output so you can install fewer panels while still covering your energy needs.
How Much Energy Does The Average House Use
While house size is relatively straightforward, determining the amount of energy used by the average house is a bit trickier. The answer depends on whether somebody lives in the city or the country, how fuel-efficient their house is, and the climate.
The different states show a large range in average household energy use. As of 2014, an average household in Hawaii used 506 kilowatt hours per month. By contrast, an average household in Louisiana used the most energy: 1291 kwh per month. The average between those two extremes is 911 kWh per month the citizens of Ohio, who, on average, use 901 kWh, come closest to matching that average.
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Questions Chat With Us
Wil has been a part of the solar industry for over 20 years as an electrician, solar installer, support technician, and more. He’s also been living off-grid since 1996. Wil and the rest of the Unbound Solar team are here to answer any questions you have about designing a system that will fit your needs.
How Many Solar Panels Do You Need For 1000 Kwh Per Month
A family with several siblings can easily reach a monthly consumption of 1,000 kWh. In places with expensive electricity, this results in monthly electric bills of over $200. However, solar power is an effective solution to reduce energy expenses.
As explained above, the number of panels needed to reach 1,000 kWh per month changes depending on local sunshine and panel wattage. To simplify calculations, solar radiation is specified in peak sun-hours per day. Weather scientists calculate this value by measuring the total sunshine in a location and converting it to equivalent hours of peak sunshine.
- Peak sun hours should not be confused with daylight hours
- Since sunlight is moderate in the early morning and late afternoon, these hours do not count as complete peak sun hours
- You may find a site that gets 12 hours of average daylight, and 6 peak sun hours per day
There are many online databases that provide peak sun hours based on site coordinates, including the Atmospheric Science Data Center from NASA. Once you know the peak sun hours, estimating the number of solar panels needed for 1,000 kWh is simple.
- The first step is calculating the kilowatts needed. You must simply divide the average daily kWh by the peak sun hours
- Assuming a 30-day month, an electricity generation of 1,000 kWh is equivalent to 33.33 kWh per day
- If the site gets 6 peak sun hours per day, you need 5.56 kilowatts
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Factors That Influence How Many Solar Panels You Need
To determine how many solar panels are needed to power a house, several factors must be considered. For example, if there are two identical homes powered by solar energy in California and New York, with exactly the same energy usage, the California home will need fewer solar panels because the state gets more sunshine.
The following are some of the most important factors to consider when figuring out many solar panels you need: