Solar Energy Installation: Frequently Asked Questions

Solar panels work best on roofs that are:

• Flat or south-facing
• Clear of equipment like vents or HVAC units, etc.
• Sunny! Look for a spot with minimal shade from trees or nearby buildings.
• Structurally sound and with a remaining life expectancy of 20 years

While the above criteria make for an ideal situation, they do not necessarily rule out other rooftop situations.

Your system will produce electricity during daylight hours. On particularly cloudy days or at night, your solar energy system will not generate electricity and your power will be provided by our energy grid. Solar panels work best in cool, sunny weather.

A certified installer can help you configure a system that will meet your needs. Installers will generally try and build a system to offset your annual energy (kilowatt-hour) usage. The actual amount of energy generated by the system at any given time depends on both the availability and intensity of the sunlight. The New York State solar map can give you an estimate of how much electricity can be generated by a solar system on your building.

As per New York state law, grid-connected solar systems will shut down for safety reasons during a power outage. If you'd like to enable your system so that it will stay on, even in the event of a greater power outage, you can do so through the use of an inverter or by installing batteries. For more information, email DGExpert@conEd.com, or visit Sustainable CUNY.

Once your installation is complete, there is no specific maintenance that needs to be performed by a technician or contractor. However, washing your solar panels a few times a year helps your system run at its best.

Generally, as a solar or photovoltaic system ages, its output decreases by about 1 percent each year. The majority of new solar energy systems include a 20-year warranty for problems not related to aging.

For more information on solar energy and to see whether or not residential solar is the right choice for you, check out this guidebook (PDF) by the Edison Electric Institute and Louisiana State University.

A net meter measures the difference between the energy produced by a customer's own generator (e.g., solar) and the energy that customer uses from Con Edison's grid. Customers who generate their own electricity via a solar system (or other alternative source) are able to transfer any electricity they do not use back into the grid in exchange for credits on their utility bill. This transfer of energy for credits has the potential to reduce a customer's monthly electricity bill.

Any excess power will be exported back to the energy grid and credited to your Con Edison account in the form of private solar usage credits.

If your solar installation does not generate enough electricity to meet your needs, Con Edison's grid will make up the difference. If you use more electricity from the grid than your renewable system generates, your net consumption is positive, and your Con Edison bill will include charges for the amount of kilowatt-hours used. Any private solar generation credits left over from your prior billing period will be applied.

The meter from your installer measures the total energy produced by your system before it is converted into energy that can be used by your home. (The energy produced by your panels must be converted into AC energy so that it is compatible with the grid, and there is some energy lost in the conversion process.) The net meter installed by Con Edison measures the difference in the energy generated by your system and the energy you use from the grid.

Your demand for electricity is measured by a demand meter that records how much electricity you use (measured in kilowatt-hours) and the rate at which you use it (measured in kW).

We need to calculate your demand so we can make sure that we're able to supply enough energy to meet the maximum needs of all of our customers at any given time.

Yes, if you paid demand charges before you installed solar panels (this applies only to certain commercial customers). Residential customers are not billed demand charges.

Demand charges cover Con Edison’s cost to maintain our facilities to meet our customers’ maximum energy needs. Solar panels can offset your overall energy consumption, but they typically do not reduce your monthly demand.

Even if you don’t use Con Edison’s energy grid, you will be billed for a basic service charge that covers the administrative costs associated with maintaining your account. This charge is not energy based.

The energy you produce and consume offsets the energy you would normally purchase from Con Edison, and is valued at the same amount that you would pay Con Edison for those kilowatt-hours. The actual cost per kilowatt-hour will vary per billing period and is based on individual customer usage patterns. For more information, see Rider R in our electric tariff.

The avoided cost of energy is determined by the average wholesale price of energy for the year, increased by 6.6 percent. This figure is then multiplied by the total number of credits in your solar bank. The resulting dollar amount is applied to your account.

No. Under Budget Billing, Con Edison reviews your billing history to calculate an average monthly payment that allows you to spread your energy costs out evenly over the year. If you’re using a net meter, your consumption can vary greatly from month to month and season to season.

If you are already on a Budget Billing plan, please contact us so that we can change your account settings. You can choose to remain enrolled; however, this is not recommended.

The value of your private solar generation credits will be the same whether you purchase your supply from an energy service company or directly from Con Edison. However, depending on your specific contract, you may be responsible for any non-usage-based or value-added service charges. To avoid additional financial impact, you should contact your energy service company with any questions or concerns.

This is called "master-metering." Each apartment must have its own sub-meter, and the account owner must apply to the Public Service Commission in order to sub-meter their tenants. It’s possible to physically re-wire the inside of your home to combine accounts, but this will be at your cost. Depending on associated usage at the house, service rates will vary, and Con Edison will need to do an inspection to remove the unused meters from the premises.