Depending on where you live, solar power can be a great option to both reduce your energy costs and your home’s carbon footprint. But, is your home ready for solar, and how much upgrading will you need to do?
In most cases, you will not need to upgrade your existing electrical panel to add solar energy to your home. You will only have to upgrade if your current breaker box is too small, old, or rated for a lower amperage. For homes built after 2000, you’ll likely only need to add the electrical transfer switch and battery storage cells. The upgrade is relatively inexpensive for older homes and should make your home safer and more compliant with future regulations.
You can probably determine if your home is solar-ready by reading through this article and following our guide to assessing your current electrical panel and breakers.
What Makes an Electrical Panel Solar Ready?
Your electrical panel is used to distribute power to the various circuits throughout your home. The breaker box receives the electricity from the main source, whether the public grid or your private solar system.
At the panel, electricity coming in from the source is distributed to each circuit throughout your home via breakers. So, your kitchen may be on its dedicated circuit, which could have a 20-amp or 30-amp breaker.
If the kitchen circuit has a short or becomes overloaded, the breaker will shut off electricity to that circuit, allowing all others to continue working. Having breakers helps to prevent electrocution or fires.
Each circuit has a breaker, and the whole panel has a main breaker that is rated by the Amperage for your entire home.
To be ready for solar, your main breaker needs to be rated for at least 200 amps in most cases. Electrical panels rated for less than 200 amps will most likely not handle the power load from the solar panels and could cause an electrical fire or other issues.
How Do I Know If I Need to Upgrade My Electrical Panel?
If you are shopping around for solar panels and getting quotes, be aware that most do not include the cost of upgrading your electrical panel. To avoid surprises later on, you can evaluate your existing panel.
First, locate your electrical panel outside the house or in a basement or utility closet.
After you have loathed the panel, open the front cover to expose all the breakers. In most cases, you will see two columns of breakers and a large breaker above them. The large breaker is the main and controls the electrical load for the entire home.
If the breaker is rated less than 200 amp service, you will most likely need to upgrade it, but you should be solar-ready if it is 200 amps.
Is it Worth Upgrading an Electric Panel for Solar?
Upgrading your panel to make it solar-ready is essential to get the full benefits from your investment and ensure that it will operate safely. If the electrical panel is not rated for the electrical load supplied by the solar panels, it could catch fire or have other issues.
Replacing the panel is not very expensive. Generally, it can cost between $1,000-$3,000 to replace a panel, depending on the system and the quality of the new panel. Considering typical solar installations cost $15,000 and $25,000, upgrading the breaker box is not cost-prohibitive.
Upgrading the new panel will also give you peace of mind knowing that it can handle the power load you put on it. Many older homes were not designed with many appliances, computers, and TVs that most modern homes have.
It is estimated that about 13% of home fires are caused by old electrical equipment and appliances, so upgrading is generally a good idea.
Lastly, if you plan to purchase an electric vehicle, that will require an additional 220 V outlet and a 40 amp breaker. California is shifting legislation to require homes to have this capacity, and many other states may soon follow suit.
Do I Need to Install a Critical Load Panel?
In addition to a new electrical panel, you may also want to evaluate the need for a critical load panel.
Critical load panels are generally used when installing a battery storage system and your solar panels. A critical load panel isolates only the most essential appliances in your home.
Having one helps you get the most out of your battery system and ensure that you have power going to the most critical areas where it is needed. Some of the things that you would exclude from operating when you are running on stored battery power include:
- Washers and dryers
- Hot tubs
- Home theater systems
Like the upgraded electrical panel, a critical load panel is not very expensive and generally costs about $1,000-$2,000 to install.
How Do I Calculate My Home’s Power Consumption?
Before you purchase a solar system or evaluate your electrical panel for upgrading, you need to have an idea of your home’s typical energy consumption. This means adding up all the power your home uses for lighting, appliances, heating, cooling, and anything else.
You can do the math yourself to estimate your electrical load and better understand your unique needs.
- Estimate the total lighting and outlet needs by multiplying the square footage of your home by 3 Watts.
- Add 1500 Watts for every kitchen and laundry room circuit you have.
- Add the Wattage for any appliance on its own circuit, like water heaters and air conditioners. You can check the labels on the appliances to get this value.
- Add up the three values above.
- Next, subtract 10,000, and multiply the remaining value by 40% (0.40).
- Add this number back with 10,000
- Now, add the Wattage of your central HVAC system.
- This gives you your total Wattage demand. To get the Amps needed, divide this number by 230.
After dividing the number by 230, you will estimate the total Amps needed to power your home. This should help you understand the size of the solar system you need and determine whether or not you need to upgrade your electrical panel.
Of course, you will want to err on the side of caution, so always round up when purchasing equipment. If your calculation comes to 160 amps, purchase 200 amps worth of solar and an electric panel rated to at least 200 amps.
How Many Solar Panels Do I Need for a 200 Amp Service?
Now that you know your home’s energy needs, you can calculate the amount of solar necessary to power it.
For this, you want to understand your home’s typical energy usage, not the Amperage drawn as in the section above. You will need to look at your last electric bill and find how many kWh you use in a month.
This number can vary based on the size of your home and whether or not you have air conditioning. The typical US home uses about 900 kWh per month. But, a small house without air conditioning uses about 20 kWh per month, while a large home with air conditioning can use around 2,000 kWh per month.
Now you know how much energy you need in a month, but we need to know the daily use to estimate your solar needs. Take the number of kWh/month and divide it by 30 to get the kWh/day, then divide by 24 to get the demand per hour.
Because the panels will not be operating at peak performance all day, it is recommended to add 25% to this number (multiply by 1.25.) Next, convert this value from kWh to Wh by multiplying by 1,000.
Now divide that by the number of peak solar hours per day to know how many solar panels you would need to power your entire home.
Below is an example, assuming the typical US home (900 kWh/month), in Florida (peak sunlight of 4.5 hours per day), using 150 Watt solar panels:
- 900 kWh/month divided by 30 days/month = 30 kWh/day
- 30 kWh/day divided by 24 hours/day = 1.2 kWh
- 1.2 kWh/hour plus 25% = 1.56 kWh
- 1.56 kWh/hour times 1,000 = 1,560 W
- 1,560 W divided by 4.5 peak hours sunlight = 346 W
- 346 W divided by 150 W per panel = 2.3 panels
So, in the example above, you would need three panels to supply your daily energy needs. You will find that your home’s needs differ from this value based on your current energy demands.
How Much Storage Capacity Do I Need?
Many solar systems supplement what is coming in from the grid to reduce your home’s energy costs. Others may use a smart meter that regulates where energy is drawn from, using grid energy when panels are insufficient and putting power back into the grid when there is a surplus.
By having a smart meter, you could get negative energy costs by overbuilding your system and even get a check from the energy company each month rather than a bill. Of course, this depends on where you live, so check local regulations.
What’s becoming more popular is storing surplus energy for times when the sun is not shining. Storage is accomplished by installing a battery bank in your house.
Both lead-acid and lithium ions batteries are suitable for this purpose. Lead-acid batteries, like those in your vehicles, are the cheapest option. But, they do not last as long and require deep cycling to charge correctly. Lithium-ion has higher up-front costs but will last much longer.
Batteries are rated in terms of Amp Hours, the number of hours they can run at a given Amperage. So, a 400 amp-hour battery can run at 4 amps for 100 hours. You can convert this to kWh by multiplying ti by the voltage and dividing by 1,000.
So, a 400 amp-hour battery running at 6 volts would supply 2.4 kWh of power (400 x 6 ÷ 1,000). If your home uses 30 kWh daily, it would require 13 batteries (30 ÷ 2.4 = 12.5).
Again, you will want to budget for a bit extra to compensate for faulty batteries, poor charging, loss to inverters, and other losses in the system.
What Other Expenses Should I Anticipate When Going Solar?
In addition to a possible new electrical panel and critical load panel or optional storage capacity, there are a few other things to include in your budget.
1. Roof Repairs
The first is to consider the condition of your roof. In some cases, your roof may require modifications or repairs before installing solar panels on it. Solar panels are rated to last about 25-30 years, which may be longer than your current roof.
If you expect your roof to need replacement before the end of the solar panel’s life expectancy is exceeded, replace the roof before installation to save many headaches and money down the road. It can cost about $10,000 to have solar panels removed and reinstalled.
2. Trimming or Removing Trees
Any trees that cast shade on your panels will reduce their efficiency and daily energy production. While it can be upsetting to have to remove old trees, this is something you might have to consider depending on the location of the solar installation and the trees you have around.
Consider this when planning your installation or deciding what is best for you in changing the system or removing trees.
3. System Components and Hardware
Your solar system will require other hardware and components such as cables, inverters, and storage containers. These will all add to the final installation cost, so budget for these in advance.
Once you have determined the approximate costs for the system you want, you can contact installation services to get a quote. Most likely, they will come out and re-evaluate your home, the roof, and the system you have designed to give you an accurate installation cost.
But now that you understand your needs and the prices of panels and batteries, you will not feel overwhelmed by their quote and can tell them precisely what you want.
Solar energy can help to improve your home’s energy security by making you less reliant on regional power grids. It also allows you to reduce your carbon footprint by using renewable energy to meet your demands.
Moving to solar can be an excellent investment in your future, and many locations offer tax breaks, loans, and other incentives to make this shift easier on your wallet. Be sure to check what programs are available in your area to help you make this change as cheap and straightforward as possible.