Sears markets the Kenmore product line, which has many appliances. Defining the difference between the Kenmore 70 and 80 series is difficult because each series carries different appliance models. Also, you generally need more than a series number to get useful information about products in a Kenmore line.
The Kenmore 70 and 80 series has several models. Used appliance stores and other retailers sell most of the models because Sears has phased out or renamed appliances in each series. You can get more information about the differences between appliances in the 70 and 80 series if you have model numbers and serial numbers. You also need those numbers to find the correct replacement parts for a Kenmore appliance.
Some washers and dryers in the 70 and 80 series have their own features. A 70 series electric dryer, for example, might have a moisture sensor that detects the amount of moisture in laundry and adjusts the time needed to dry it. The feature helps prevent users from over-drying clothes. Some 80 series washing machines can wash extra large loads of clothing at one time. Those models are typically called "super capacity" or "extra capacity" machines.
Serial numbers on Kenmore appliances identify different manufacturing dates. Serial numbers on 70 and 80 series appliances usually have two letters followed by a seven-digit number. The second letter indicates the year the appliance was made. For example, the F in the 80 series washing machine serial number CF4227224 indicates the machine was manufactured in 1996. The L in the serial number CL2636932 for a 70 series washer indicates the machine was made in 2001. The Appliance 411 website allows users to do date code searches to determine manufacturing dates.
Sears doesn't manufacture any of its appliances, so different companies have made 70 and 80 series products. You need the Kenmore model number to determine which company made a specific appliance. Model numbers in the 70 and 80 series are usually 11 digits. The first three numbers indicate which company made the appliance. The model number 110.92380200 on an 80 series washing machine indicates that Whirlpool was the manufacturer. Several websites have charts listing Kenmore appliance codes for manufacturers, including the Appliance 411 site.