United Illuminating's online payment system lets you pay your bill from your computer or phone without calling or mailing a check
United Illuminating (UI) operates an online bill pay portal where you can view your bill, make one-time payments, and set up automatic payments. You do not need to create a separate account — you log in with your account number and service address, the same information on your paper bill. Payments typically post within one business day for online submissions made before 5 p.m. Eastern time.
The system accepts payments by bank account (ACH transfer) or debit card. Credit card payments are not available through UI's portal, though some third-party payment processors may offer that option at a higher fee. If you pay by bank account, there is no fee. Debit card payments carry a fee set by the payment processor, usually between $2 and $4 depending on the transaction amount.
Key Takeaways
- Log into UI's bill pay portal at uiogn.uigen.com using your account number and service address to view and pay your bill online.
- Bank account (ACH) payments are free and post within one business day; debit card payments charge a fee of $2 to $4.
- You can set up automatic monthly payments so your bill is paid on the same day each month without logging in again.
- If you cannot pay your full bill, contact UI directly about budget billing or hardship programs rather than making a partial payment.
Logging in and finding your account number
Your account number appears on your paper bill in the upper right corner, usually formatted as a series of digits. If you do not have a recent bill, you can find your account number by calling United Illuminating at 1-800-UI-LIGHT (1-800-845-4444) or by checking any past correspondence from the company.
Go to uiogn.uigen.com and enter your account number and the service address exactly as it appears on your bill. The system will pull up your current bill and payment history. If the address does not match what UI has on file, the login will fail — contact UI to confirm your address is correct before trying again.
Making a one-time payment
After logging in, select "Make a Payment" or "Pay Now." The portal will show your current balance and the due date. You can pay the full amount or enter a different amount, though paying less than the full balance will leave a remaining balance due on your next bill.
Choose your payment method: bank account or debit card. For bank account payments, enter your routing number and account number. For debit card, enter the card number, expiration date, and CVV. Select the date you want the payment to post — this is usually the same day if submitted before 5 p.m. Eastern time, or the next business day if submitted after hours or on a weekend.
Review the payment details and confirm. You will receive a confirmation number on screen and by email. Keep this number in case you need to reference the payment later.
Setting up automatic monthly payments
Automatic payments remove the need to log in each month. From the bill pay portal, select "Enroll in AutoPay" or "Set Up Automatic Payments." Choose whether you want to pay the full bill amount each month or a fixed dollar amount you set yourself.
If you choose to pay the full bill amount, your payment will adjust each month based on your usage. If you choose a fixed amount, you will need to log in occasionally to check whether your payment covers the full bill, especially during high-usage seasons (summer for air conditioning, winter for heating in Connecticut).
Automatic payments are deducted on the due date shown on your bill. You can cancel or change the payment amount at any time through the portal, and changes take effect on the next scheduled payment date.
What to do if you cannot pay the full amount
If your bill is higher than you can afford, do not make a partial payment and hope the rest goes away. Instead, contact United Illuminating directly at 1-800-UI-LIGHT to discuss your options. UI offers budget billing, which spreads your annual costs evenly across 12 months so your bill is more predictable. You may also be may be able to access for hardship programs or payment arrangements that let you pay over time.
Partial payments do not stop late fees or service disconnection if the full balance is not paid by the due date. Calling UI before the due date gives you time to set up a plan that protects your service.
Troubleshooting common login and payment issues
If you cannot log in, the most common cause is a mismatch between your account number or service address and what UI has on file. Double-check both against your bill. If they match and you still cannot log in, call 1-800-UI-LIGHT to confirm your account is active and your information is correct.
If a payment you submitted does not appear in your account within two business days, check your confirmation number and the payment method you used. Contact UI with this information and they can trace the payment. Do not submit the payment again until you confirm the first one did not go through, or you may be charged twice.
If you see a fee you did not expect, it is likely a debit card processing fee. Bank account (ACH) payments have no fee. If you were charged a fee on an ACH payment, contact UI to report it.
Payment deadlines and late fees
Your due date appears on your bill. Payments submitted online before 5 p.m. Eastern time post the same day; payments submitted after 5 p.m. or on weekends post the next business day. Plan to submit your payment at least one business day before the due date to avoid a late fee.
If your payment posts after the due date, UI will charge a late fee. The amount varies but is typically a percentage of your bill or a flat fee — check your bill or call UI to confirm the current late fee amount. Late fees are separate from your regular bill and will appear on your next statement.
Frequently Asked Questions
Can I pay my UI bill with a credit card online?
No, United Illuminating's online portal does not accept credit cards. You can pay by bank account (free) or debit card (with a fee). Some third-party bill pay services may allow credit card payments, but they typically charge a higher fee than UI's debit card option.
What time does my online payment post?
Payments submitted before 5 p.m. Eastern time on a business day post the same day. Payments submitted after 5 p.m. or on weekends post the next business day. Plan ahead if your due date falls on a weekend or holiday.
Can I change or cancel an automatic payment after I set it up?
Yes. Log into the bill pay portal and select the automatic payment to modify the amount, change the payment date, or cancel it entirely. Changes take effect on the next scheduled payment date, so cancel at least one business day before the payment is due if you want to stop it immediately.
What happens if I pay less than my full bill?
The remaining balance carries over to your next bill and will accrue a late fee if not paid by the new due date. If you cannot pay the full amount, call UI at 1-800-UI-LIGHT to set up a payment plan or budget billing instead of making a partial payment.
Do I need to create a separate account to use bill pay?
No. You log in with your account number and service address from your bill. You do not need a username or password unless you choose to create one for faster future logins.