Appliance dimensions and clearances

An appliance has three dimensions and only the first one is printed on the front of the box. There is the body, which is what you buy; the opening, which is what the joinery has to leave; and the operating envelope, which is the body plus the air gap plus the door swung open plus a person standing in it. Kitchens fail at the third of those far more often than the first, and they fail after the cabinets are made, when nothing can be moved.

The cutout is the datum, not the appliance#

Every specification sheet gives two sets of numbers, and the one that matters is the opening. A standard dishwasher is built at about 23.75 in (603 mm) wide to fit a 24 in (610 mm) opening 34 to 34.5 in (864 to 876 mm) high. A wall oven is quoted by nominal width, 24, 27 or 30 in (610, 686 or 762 mm), but installed by cutout, which is neither of those. Dishwasher dimensions and clearances and wall oven dimensions and mounting heights work from the cutout in each case, because that is the number a joiner cuts to.

Height is the sneaky one under a counter. The 34.5 in (876 mm) opening assumes a finished floor. Lay 3/4 in (19 mm) of engineered board and underlay after the carcasses go in and the machine can be slid under but never lifted out for service without removing the worktop, which is a genuinely common and genuinely expensive discovery.

24 in against 600 mm, and the 9.6 mm between them#

The kitchen world runs on 24 in in North America and 600 mm in Europe, and the difference is 9.6 mm. That is small enough to look like a rounding error and large enough to leave a gap you can see from the doorway, or to stop a machine entering a carcass altogether. It compounds along a run: five units apart and the two systems are nearly 2 in (48 mm) out of step, which is where filler strips come from. Imperial and metric dimension systems traces the collision through a whole kitchen, and appliance sizes by country gives the national families side by side. If the kitchen is small enough that the compact family is in play, the trade-offs are set out in compact and apartment appliance sizes, and panel-ready machines add their own 3/4 in (19 mm) of door thickness in front, which integrated appliance panel dimensions accounts for.

Air gaps are not tolerance#

The gap around a cooling appliance is functional. Fridges typically want 1/2 in (13 mm) at each side, 1 in (25 mm) behind and 1 in above, and built-in columns often want 2 in (50 mm) at the top for the discharge from the condenser. A wine cabinet packed into a tight run with its vent obscured will hold temperature in winter and drift in August: refrigerator dimensions and clearances and wine fridge and beverage centre dimensions set out what each type needs. Extraction is the same argument upward. A hood must be at least as wide as the hob and preferably 3 in (76 mm) wider each side, mounted 24 to 30 in (61 to 76 cm) above an electric surface or 27 to 36 in (69 to 91 cm) above gas, with a capture depth that reaches the front burners: range hood sizes, mounting heights and capture area ties the three together, and the hob widths it works from are in range and cooktop dimensions.

The oven at 30 to 36 in and the microwave at 66 in#

Two appliance heights are chosen rather than given, and both are usually wrong by default. A wall oven wants the base of its cavity at 30 to 36 in (76 to 91 cm) so the second rack lands near the elbow, with a landing surface within 18 in (46 cm) for the hot tray. An over-range microwave is a compromise between 30 in (76 cm) of clearance above the hob and a reach to its own turntable, which finishes with the top of the unit near 66 in (168 cm) and a hot bowl coming out above shoulder height. Microwave dimensions and placement heights argues the case for putting it somewhere else, and the tall-unit stack that holds an oven, a coffee machine and a steam oven is dimensioned in built-in coffee machine and steam oven dimensions. The counter these heights are measured from is itself a variable, which kitchen counter and cabinet heights covers.

Water heaters, air handlers and the 36 in in front of them#

Half the appliances in a house sit outside the kitchen and get planned last, which is why they end up in cupboards that cannot be opened. A tank water heater needs 6 in (152 mm) around it and 24 to 30 in (61 to 76 cm) of clear front access, and in a garage the ignition source of a fuel-burning unit sits 18 in (457 mm) above the floor under the IRC: water heater and boiler dimensions and clearances covers the flue separations as well. Air handlers and heat pumps are governed by service space rather than by size, with the NEC asking for a clear working space 36 in (914 mm) deep and 30 in (762 mm) wide at electrical equipment, and outdoor units needing free air on every face: HVAC, air handler and heat pump clearances sets out both. Laundry appliances follow the same logic as the kitchen, with their own door projections, in washer and dryer dimensions, and the codes behind these figures are indexed in the standards and codes reference.