Perhaps we can argue that the coldness in the house, so vividly described, represents the harsh reality of life in the poet's time. There are a number of suggestions in the poem that seem to indicate the coldness could actually be a symbol for something else. Consider the following quote:
...and put his clothes on in the blueblack cold,
then with cracked hands that ached
from labour in the weekday weather made
banked fires blaze.
It is highly significant that it is the father who faces the cold, whose "cracked hands" are already suffering from the extreme cold. It is he who makes the "banked fires blaze," the alliteration adding emphasis to this act of creating heat, and it is the speaker who, still in his warm bed, hears "the cold splintering, breaking." The narrator never has to face the cold in its raw intensity. This perhaps indicates that the cold is a symbol for the harsh realities of life that the narrator's father does his best to protect him from.