With the aid of dendrochronology, or tree-ring dating, the Dalarna province's leading museum has shown that the timber used to build the house dates from the year 1237.
"We're delighted. There has been speculation about this since the 1920s and we have drilled and carried out tests twice before, but this is the first time we were able to confirm the date," Jan Raihle, the head of Dalarnas Museum, told The Local.
The house is a so-called eldhus (literally "fire house"), a one-room building with a fireplace in the centre.
Though currently located at Zorns Gammelgård (Old Farm), part of an estate donated to the Swedish State by the artist Anders Zorn (1860-1920), the house has previously been moved at least five times.
The farmyard on the banks of Lake Siljan is made up of around 40 houses and was designed by Anders Zorn to showcase the province's old log building traditions.
Since the mid-1990s, Dalarnas Museum has been working with dendrochronologists to date the province's impressive stock of timber houses from the Middle Ages.
"There are of course very old wooden houses all over Sweden, but Dalarna has by far the most. So far we have dated around 150 houses to the period from the 1200s to the 1500s," said Jan Raihle.
But although the Mora house is the oldest wooden residential home, it is not the oldest non-religious wooden building in the country: that honour goes to an outhouse attached to Ingatorp Church in Småland in southern Sweden.
Carbon 14 and dendrochronological studies both date the Ingatorp building to 1229, plus or minus ten years.
"It's now used as a shed for lawnmowers and such like but it may originally have been used as a weapons store," said Lennart Grandelius, who carried out the study in association with the University of Lund.
See also: Photo gallery - Ingatorp outhouse