Not sure what you mean by "most common." You mean back in the day, or now? I would venture to agree with Norgeway that Kenmore probably most common then. Back in the early-mid '70s in Northern California where I was raised, my little cul-de-sac had a glorious potpourri of household machines: we had a Wards Signature machine, neighbors around us had Whirlpool, GE, Kenmore, Frigidaire. Great fun hanging out with friends taking a sneak peek into each one!
In the little city where I grew up in the sixties, the middle and upper middle class people bought either GE or Frigidaire because that's what our local appliance dealers sold. The less fortunate bought Kenmore because Sears let them buy on time.
I saw mostly Kenmores in the 70s when I was a kid. Probably followed by GE and Hotpoint. Saw several Norge and Norge made machines also. Only saw a few Whirlpools but I would say overall Kenmore was king.
There were a lot of Kenmore's around Atlanta back in the day. Poor people bought whatever brand they could get on account. Smart people (especially with large families) bought the most they could get for their money. Kenmore was known for offering a lot of features for the money.
The Sears "Revolving Credit" made it easy to buy there. Atlanta Gas Light sold Maytag. Lots of poor people bought them because Atlanta Gas Light would just put it on their gas bill and they could pay $1 a month for years if they wanted to. That made both Atlanta Gas Light and Maytag a lot of good friends.
Mom and Pop stores sold TONS of Frigidaires----same story----flexible payment plans.
Rich's Department store sold GE. Same story.
When families were large and money was tight it was always the best financing that closed the deal.
There were also Kelvinators, Speed Queens, Norges, Philco-Bendix, Westinghouse and Whirlpools around, and I assume the best deals came from the mom and pop stores.
Popularity of brands seemed to be a highly regional thing, especially up here in Canada. In rural areas, it would depend on the brand carried by the nearest appliance dealer - there were catalog stores here but it wasn't common for a rural homeowner to buy a washer or dryer from the Simpson-Sears or Eatons catalog!
Inglis (Whirlpool machines built in Canada under license) were very popular in most rural locations here in La Belle Province; in the greater Montreal area, there were lots of Viking (sold by Eatons) or Kenmore (sold by Simpsons-Sears) because there were retail stores. This held true until the mid-70s when there seemed to be a surge in the popularity of Maytag laundry machines. But there were at least some Frigidaire, GE, and Westinghouse machines out there - I've found Canadian examples of all three brands over the years....
Whirlpool was leader in my birth-town since that was the local dealer. Western Auto / Catalina probably was second for a while. There was Easy and Philco for a brief time, only ever saw one of each. Anything else had to be bought out-of-town, or came along with move-ins. The next town west (county seat) had Westinghouse & Frigidaire & Maytag dealers (and a Sears catalog store). I knew a couple local people with Westy SpaceMates (stacked) but never saw any Westy TLs or Frigidaires. The next big town west had a large Sears store.
The next town east had Sears/Kenmore (small store, later reduced to a catalog store, now long-gone), GE, Maytag, & Frigidaire. Someone there handled Kelvinator for a brief time in the 1960s.
many places had in-store credit for appliances....
and back in the day, 50's and 60's....it was reputation of sales and service....you could buy a Frigidaire, but if a dealer didn't stand behind it, that brand and the dealer was shot down....
the Gas and Electric Company used to finance appliances they sponsored....
for the price of most Maytag or Speed Queen washers alone, you could get a nicely featured Washer and Dryer from Sears/Kenmore/Whirlpool or a GE FilterFlo
Maytag wringers were dominate in the field of washers.....yet when the Automatics came out, it was a gamble in the beginning to see if they lived up to the 'Dependable' name.....
but that was with any machine.....who had the better built mouse trap!
Gordon said to me once that he had an 80s Sears Catalog touting that Kenmore had been the top selling washer for over 30 years. I'm sure Sears, being the first to offer credit had something to do with this. It seems to me if you find an pre-80s washer/dryer around here it tends to be a Kenmore or a Maytag... at least around here.
When I was growing up in Atlanta in the 60's and 70's, the two most common brands were Kenmore and GE. Lower income families bought Kenmore because of Sears easy credit plan and middle to upper income families bought GE because Rich's Department Store, the premier store in Atlanta, was the biggest GE dealer around.
Next to Kenmore and GE, there were also quite a few Maytags and Frigidaires around Atlanta because the Georgia Power appliance stores sold those two brands.
Where I came from which is suburban Pittsburgh I noticed a lot of Maytag washers and dryers both of my Grandmothers and mom had them. In the neighborhood too, second would be kenmore and whirlpools.
My mom had a pair of 1958 GE's. Our fridge was GE as well. DW (installed 1962) was KitchenAid, as was the garbage disposal.
Our somewhat more prosperous neighbors owned a Maytag pair.
My aunt on the East Coast bought her home (in which she still lives) in 1956. The original washer (don't know the brand) lasted about eight years. The second washer, purchased 1964, was a Maytag, on the advice of another aunt. That machine lasted 43 years. She finally had to replace it in 2007 because the repair service could no longer locate replacement parts for it.
In the 50's and 60's there were several mom and pop stores. Gambles,Sears and Wards were the stores that were popular. We had a Gambles Coronado, crap but they had "Come on Deals," as my dad called which my mom fell for. The neighbor's had a GE from Duff's Appliance store. We had the Coronado from Gambles as did the neighbor behind us. Move in neighbors right next to us has Westinghouse spacemates. The seal broke on the door and breaking waves dashed high, she then got a Kenmore set in coppertone.
My aunt had a Hamilton and it didnt last long so out it went. I loved going to all of the appliance stores, and look around.
I think Kenmores would have been the top selling washing machines in the '60's, '70's and '80's before the HE machines hit the market and even then I wouldn't be surprised if they remained in the top spot before Sears stores started to dwindle.