Allstate Property & Casualty Insurance Co. is imposing an average premium increase of 33.4 percent on the roughly 45,000 Pennsylvania customers who buy only homeowner's insurance from the company.

The average increase for customers who insure both their homes and their cars with the division of Allstate Corp. in Northbrook, Ill., is 11.3 percent, according to a filing with the Pennsylvania Insurance Department. The increase was effective for renewals starting May 20.

The big jump in costs for homeowners-insurance-only customers prompted Lance Haver, consumer advocate in the Philadelphia Mayor's Office, to buy radio advertisements with his own money warning consumers of the rate increase and advising them to shop around before their renewals kick in.

Haver, in an interview Tuesday, called the two-tiered rate increase bizarre. It's as if they think there is "some correlation between your house catching fire and who you insure your car with," he said.

Brett Ludwig, a spokesman for Allstate, said Tuesday that customers who insure only their houses with Allstate have filed both more frequent and higher-cost claims. "The numbers really do speak for themselves," he said. Ludwig said the frequency of claims was weather-related, but the cost was linked to the price of labor and materials.

Overall, Ludwig said the insurer had not raised rates in six years. The last rate change was a 10 percent decrease four years ago. The increases for both types of customers, which average 18.3 percent, were forced by more frequent claims and higher costs, he said.

Typical rate increases in the state are in the 5 to 10 percent range, said Melissa Fox, state Insurance Department spokeswoman.

To soften the financial blow, Allstate doubled the discount for customers buying both home and auto insurance to 30 percent from 15 percent. "We're trying to be as sensitive as we can," Ludwig said.

For the average Allstate customer in Pennsylvania with only a homeowners' policy, the premium will rise to $934 from $700. However, if the customer adds Allstate auto coverage, that would be reduced by 30 percent. Customers can save even more by insuring two or more cars, Ludwig said.

Ludwig said Allstate agents were contacting customers about the increase.

Haver wanted the Insurance Department to notify Allstate customers. When that did not happen, he took the matter into his own hands, paying $950 to run his 30-second spot 10 times on KYW.