Being a risk of payment delinquency analysis, FICO evaluates revolving vs. installment credit differently.
Revolving credit is basically that for which you have a pre-approved amount of credit at your disposal for discretionary use. Most revolving accounts will have a pre-specified limit available, while some have an "unlimited" credit limit. Both monthly balances and payments "revolve" around the debt you have accrued.
Higher-risk revolving accounts are those for which the credit extended is not secured. They thus count a bit more in the risk analysis. Credit cards and lines of credit, including HELOCS, are traditionaly revolving lines of credit, although LOCs get a bit murky when their avaliable limits get high, and thus are sometimes scored as installment-type.
Installment credit is basically that for which you sign a specific contract and receive a certain amount of $ upfront, with specified contract terms for its monthly repayment.
You dont have additional, discretionary credit to draw upon. Most installment loans are secured by personal property, such as a mortgage or auto loan, and thus are much less likely to become delinquent should times get tough. Thus, they are generally not as significant in predicting risk of delinquency. Revolving is usually the first to become delinquent.
My rough guesstimate is that your discretionary use of revolving credit is weighted around 90% of your utilization scoring. It is certainly significantly higher than installment.
