Understanding Your Solar Electric Bill: A Complete Guide

Have you recently installed solar panels and found yourself confused by your electric bill? You're not alone. Many homeowners look at their first post-solar bill and think, "This can't be right!" Today, let's decode the mystery of solar billing and help you understand exactly what those numbers mean.

The Basics: Your Two Power Sources

When you go solar while staying connected to the grid (which most people do), you have two sources of power:

1. Your solar system
2. The utility company

Most homeowners choose to stay grid-tied because going off-grid is extremely expensive. Plus, having the utility as a backup power source for nights and rainy days is both important and cost-effective.

How Solar Power Flows

Here's what happens with your solar power:

1. Solar panels generate electricity on your roof
2. The inverter converts DC power to usable AC power
3. This power FIRST feeds your home
4. Only excess power goes back to the grid

The Crucial Part Many Miss

Here's the key point that often confuses homeowners: The meter only shows excess power that wasn't used by your home. Let's break this down with an example:

If your solar system generates 20 kWh in a day:

• Your home directly uses 12 kWh
• The remaining 8 kWh goes to the grid
• At night, you might need 5 kWh from the grid
• Total daily consumption = 17 kWh (12 from solar + 5 from grid)

Reading Your Bill

Your utility bill will show two main figures:

1. Charges (or "delivered" power) - What you bought from the utility
2. Credits - What you sold back to the grid

Pro Tip

Request your utility provider to change your billing cycle from the first to the last of the month. This makes calculations much easier!

Real-World Example

Let's look at two billing cycles from my personal solar system:

Spring (March-April)

• Total Solar Production: 1,268 kWh
• Sold to Utility: 911 kWh
• Direct Solar Usage: 357 kWh (1,268 - 911)
• Bought from Utility: 392 kWh
• Total Home Usage: 749 kWh (357 + 392)

Summer (July)

• Total Solar Production: 1,161 kWh
• Sold to Utility: 394 kWh
• Direct Solar Usage: 767 kWh (1,161 - 394)
• Bought from Utility: 1,082 kWh
• Total Home Usage: 1,849 kWh (767 + 1,082)

Tips for Maximizing Your Solar Benefits

To get the most from your solar system:

• Use more power during daylight hours
• Run appliances like washing machines and dishwashers during peak sun
• Start cooling your home before sunset
• Charge EVs during solar production hours

Monitoring Your System 

Modern Systems

Many newer systems come with CT (Current Transformer) monitoring, which measures power flow automatically.

Older Systems

For older systems without monitoring, you can add third-party options like:

• Solar Sense
• Emporia monitoring device These cost less than $200 and can provide valuable usage data.

The Bottom Line

Remember: Your utility bill only shows what you exchange with the grid - what you buy from them and what you sell to them. It doesn't show your total solar production or home consumption. Understanding this distinction is key to making sense of your solar investment.

How to Check if Your System is Working Properly

Compare the same months year over year:

• Check total production
• Compare grid purchases
• Look at excess solar sold
• Consider usage changes (new appliances, more people at home, etc.)

This way, you can spot any significant changes that might indicate a problem with your solar system.

Note: This guide covers grid-tied systems without batteries. Stay tuned for our upcoming guide on systems with battery storage!

Need More Help?

If you're still unsure about your solar billing, start by:

1. Downloading your solar production data
2. Gathering your utility bills
3. Comparing the numbers using the formulas above
4. Reaching out to your installer if something doesn't add up

Remember, understanding these numbers helps you maximize your solar investment and ensure your system is working as intended.

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