A washer that fits the house is one that finishes the week's laundry before the week runs out. Start with the load count and the heaviest day, not with the drum size on the box.
Count the loads in a week
Write down how many loads the house runs in a typical week, including bedding, towels, work clothes and children's clothes. Note which day runs heaviest. A household that washes most of its loads on one day needs more capacity on that day than the weekly total suggests.
Note the bulky items
Comforters, rugs, sleeping bags and heavy work clothes set the real size of the drum you need. Check that the stated capacity holds the largest item in the house without crowding. A washer sized only for everyday clothes will push bulky items into a second cycle, and that doubles the time on a busy day.
Time a full cycle
Time one full cycle with the settings you would really use, including the spin speed and any extra rinse. Multiply that time by the loads you run on the heaviest day. If the total runs past the hours you have available, the washer is undersized for the house, even if its capacity looks right on paper.
Measure the room and the opening
Measure the width of the door or doorway, the depth of the space with the lid open and the clearance behind the unit for the hoses and the cord. Check that the floor is level, since an uneven floor affects spin balance in every household. Leave room for the door to swing and for a person to reach the controls without stretching.
Check the drain and the supply
Confirm the drain standpipe height, the cold and hot supply valves and the outlet the machine will use. A household that runs several loads on a busy day benefits from a drain that can take a full discharge without backing up into a sink.
Keep the sizing notes with the install record
Write the household count, the heaviest day and the room measurements on the same sheet as the install year. In later years those notes help you decide whether to repair the unit, replace it or move it to a room that suits it better. For the service life figure and a planning date, see the clothes washer page. To compare the wider set of major appliances, see the ranked list of major appliances.