Convection, Combi, Deck or Hydrovection: Which Commercial Oven Does Your Menu Need?

"Commercial oven" covers four machines that do not do the same job. A convection oven, a combi oven, a deck oven and a hydrovection oven all bake, but each one is built around a different menu. Pick by what you cook most, not by capacity or price, and the rest of the decision gets short. This guide compares the four types, then works through the two questions every one of them raises: what it needs from your building, and how many pans it really takes.

The four types in one table

Convection: the default for most kitchens

If you are not sure, you want a convection oven. It takes a full-size 18 × 26 sheet pan on each of five racks, cooks all five evenly, and does 80% of what most restaurants ask an oven to do. The Flamaster 38" cabinet is the reference point in this store:

All four run 150°F to 500°F with independent full-view doors, and the cooking area is 29" × 22 1/2" per deck — a full sheet pan loaded sideways. The gas-or-electric question is worked through with real efficiency numbers in Commercial Convection Ovens: Gas or Electric, Single or Double Deck; the short version is that they deliver the same heat to the food, and the choice is about which utility you can get to the spot.

Combi: one oven instead of three

A combi oven adds controlled steam to a convection cavity. At 100% steam it replaces a steamer; at 0% it is a convection oven; in between it roasts a prime rib with less shrinkage than dry heat can. Blodgett builds them from compact 6-pan units up to 20-pan floor models, in gas and electric, with two steam systems:

• Boiler models generate steam in a separate tank — faster steam, more precise, more to maintain (descaling on a schedule).
• Boilerless models spray water onto the heating element — simpler, cheaper to own, a little slower to reach full steam.

Two things a combi asks for that a convection oven does not: a water line and a floor drain at the oven location, and training. A combi that nobody programs is an expensive convection oven. If your menu has steamed vegetables, rice, sous-vide retherm and roasting all fighting for space, it earns its price; if you bake sheet pans of the same thing all day, it does not.

Deck: pizza and bread

A deck oven cooks from below through a stone or steel hearth, with no fan. That is what gives a pizza a crisp, blistered bottom and a loaf of bread proper oven spring — a convection oven's moving air dries the surface before the crust sets. Blodgett's 1048 and 1060 series are the gas pizza decks (48" and 60" wide, stackable two or three high); the 900 series covers bakery and pizza decks in single, double and triple stacks. Capacity is counted in pizzas per deck, and the answer to "how many decks" is usually "one more than you think" because you are cooking at 500–650°F and every door opening costs recovery time.

Hydrovection: moist roasting without a boiler

Blodgett's Hydrovection sits between convection and combi: a convection oven with a water injection stage that adds humidity during the cook. It roasts chicken and prime rib with less weight loss than dry convection, at a lower price and with none of the boiler maintenance of a combi. It needs a water connection; check the spec sheet of the specific model for drain requirements. Best fit: cafeterias, hotels and banquet kitchens that roast in volume and rarely need true steaming.

What each one needs from your building

• Gas convection still needs a 120V outlet for the fan and controls. Order it configured for NG or LP — converting is an orifice and pressure change, not a switch. See natural gas or propane.
• Electric convection at 10 kW / 240V draws about 42 A continuous, which the electrical code sizes to a 60 A circuit, hardwired. Double-deck is two of those.
• Combi and hydrovection add a water supply (filtered — scale is the number-one combi failure); combi ovens also need a drain.
• All of them need a hood decision made with your local inspector before delivery. Whether a given oven can sit under a Type II condensate hood or needs a Type I grease hood depends on what you cook in it, not just on the oven.

Sizing: think in pans, not cubic feet

Ovens are bought by throughput. Count how many full sheet pans (or hotel pans, for a combi) you need in the oven at your busiest hour, divide by how long each batch takes, and that gives the rack count. A single 5-rack convection deck cycles roughly 60–100 sheet pans over a four-hour service on 15-minute bakes; if the menu needs two temperatures at once — rolls holding at 200°F while sheet pans roast at 425°F — a double deck with independent chambers beats two singles on floor space and beats one single on time.

Keeping it running

Door gaskets, fan motors and thermostat calibration are the three things that quietly cost you consistency. The daily, weekly and annual maintenance checklist covers all three for convection ovens; combi ovens add descaling and cleaning cycles on top.

Which one, in one line each

• Convection — sheet-pan volume, roasting, reheating; the default
• Combi — a multi-station menu that needs steam, and a crew who will program it
• Deck — pizza and bread
• Hydrovection — high-volume moist roasting without a boiler