The Frigidaire FDPC4221AS is the entry model and the FDSP4501AS is the step up: both are 24-inch built-in dishwashers, but the FDSP4501AS adds a third rack, the BladeSpray Arm, EvenDry, DishSense soil sensing and a stainless steel tub, holds 14 place settings instead of 12 and is rated 49 dBA instead of 62 dBA. If a quiet kitchen and a third rack for utensils matter to you, the FDSP4501AS is the one to pick; if you want a plain, working dishwasher with two wash cycles, the FDPC4221AS does the job.
What is the real difference between the FDPC4221AS and the FDSP4501AS?
Everything in the comparison comes from the two model pages on our site. The FDPC4221AS page describes a 24-inch full-console dishwasher, an entry model with 12 place settings, two wash cycles and Energy Saver Dry, rated at 62 dBA. The FDSP4501AS page describes a 24-inch top-control, fully integrated dishwasher with 14 place settings, a stainless steel tub, a third rack, the BladeSpray Arm, EvenDry and DishSense, rated at 49 dBA. Both are listed as current models and both are 24 inches wide; check your cabinet opening and the installation sheet for the exact model before you buy.
The two extra place settings and the third rack are the visible part of the upgrade. The invisible part is the sound rating and the drying system, and those are the details people notice after a few weeks rather than in the showroom.
Which one is quieter?
The FDSP4501AS. It is rated 49 dBA against 62 dBA for the FDPC4221AS, a difference of 13 decibels on the listed numbers. A lower dBA number means a quieter machine, so the FDSP4501AS is the better choice for an open-plan kitchen where the dishwasher runs while people are talking or watching television nearby. In a closed kitchen, or if the dishwasher runs overnight, the 62 dBA rating of the FDPC4221AS is less of a concern. We do not list a sound number for any dishwasher that is not on its model page, so check the rating for your exact model before you rely on it.
Does the third rack on the FDSP4501AS matter?
For many households it is the best reason to pay more. The third rack is a shallow tray above the upper basket that holds utensils and other flat items, which frees the silverware basket and the lower rack for pots and plates. The FDPC4221AS does not list a third rack, so everything goes into the two baskets. Our Frigidaire dishwasher features glossary explains the rack names and which models carry them. A practical warning applies to both machines: a tall item on the lower rack, or an overloaded third rack, can keep a spray arm from turning, so load with the arms free.
How do the drying and wash features compare?
The FDPC4221AS lists Energy Saver Dry. The FDSP4501AS lists EvenDry, the BladeSpray Arm and DishSense. EvenDry is the name of the drying system on that model, and DishSense is the soil-sensing feature that reads how dirty the wash water is and sets the cycle length to match. That is why a sensed cycle can run longer on a heavily soiled load; it is not a fault. If you prefer a predictable cycle time, choose a timed cycle where your model offers one. Our guide to the Frigidaire OrbitClean spray arm explains how a spray arm works, and the same loading rule applies to the BladeSpray Arm: the arm needs room to turn.
Neither model changes what a dishwasher needs from you. Both need a clean filter, a clear drain path, a fully open water supply and a load that leaves the arms free. A dishwasher with a better feature list still washes poorly with a clogged filter.
Do both models show the same error codes?
According to the two model pages, yes. On both, the display can show i20 and i40, which point to a drain or fill restriction, and iF0, which is listed as the same condition; i30, which means water reached the base pan and the anti-flood float tripped; iC0, a communication problem between the control boards; and UO, the vent code. The code pages explain each one in turn: i20, i30 and iC0. A code is not a reason to avoid either model, because any dishwasher shows these alerts when something restricts the drain or trips a float. The longer reference is our Frigidaire dishwasher error codes guide.
Which dishwasher should you buy?
Choose the FDPC4221AS if the budget is the priority, the kitchen is closed off from the living area and 12 place settings cover your household. It does the basic job and gives you two wash cycles and Energy Saver Dry.
Choose the FDSP4501AS if you cook often, entertain, or hear the dishwasher from the sofa. The extra capacity, the third rack, the stainless tub and the lower noise rating are the reasons to step up. We do not quote prices here, because they change by retailer and region; compare the two models side by side at the store. Whichever you choose, our Frigidaire dishwasher installation guide covers what to expect on the day it goes in.
