Pronunciation of 'house' as 'hoose':
It is a remnant of Middle English.
In Great Vowel Shift, most of the vowels were changed in many accents/ dialects while some of the old vowel sounds were remained in some dialects.
/u:/ in some accents was changed to /aʊ/ but it did not change in some Northern dialects and Scottish English.
Northern English and Scots
The Great Vowel Shift affected other dialects as well as the standard English of southern England but in different ways. In Northern England, the shift did not operate on the long back vowels because they had undergone an earlier shift. Similarly, the Scots language in Scotland had a different vowel system before the Great Vowel Shift, as /oː/ had shifted to /øː/ in Early Scots. In the Scots equivalent of the Great Vowel Shift, the long vowels /iː/, /eː/ and /aː/ shifted to /ei/, /iː/ and /eː/ by the Middle Scots period and /uː/ remained unaffected.
The first step in the Great Vowel Shift in Northern and Southern English is shown in the table below. The Northern English developments of Middle English /iː, eː/ and /oː, uː/ were different from Southern English. In particular, the Northern English vowels /iː/ in bite, /eː/ in feet, and /oː/ in boot shifted, while the vowel /uː/ in house did not. These developments below fall under the label "older" to refer to Scots and a more conservative and increasingly rural Northern sound, while "younger" refers to a more mainstream Northern sound largely emerging just since the twentieth century.
Etymology of 'hoose':
From Middle English hous, hus, from Old English hūs (“dwelling, shelter, house”), from Proto-Germanic *hūsą, of unknown origin.
From a dialectal spelling of house, from Middle English hous, hus, from Old English hūs (“dwelling, shelter, house”), from Proto-Germanic *hūsą (“house”). Compare Scots hoose.
Do not confuse 'hoose' (house) with the disease 'hoose'.
'Hoose' (disease) is pronounced as /huːz/ while 'hoose' (meaning house) is pronounced as /huːs/.