Many of the words in this poem have very negative connotations: "blueblack cold," "cracked hands," and "ached," from the first stanza, for example, seem to convey the pain that the narrator's father endured. Also, "splintering, breaking," "fearing," and "chronic angers" from the second stanza are all quite negative. The narrator's father essentially tries to protect his family from these harsh and negative experiences of the cold; this is why he gets up early, even on Sundays, to make up the fires so that his family can wait until it's warm to get out of their warm beds. The words that have positive connotations, like "banked fires blaze" or "warm," are the effects of the father's work, the way he seems to show his love. It does not seem as though the narrator's father is very affectionate or loving in a warm and obvious way; instead, he shows his love by making his family more comfortable, by enduring the cold so that they do not have to.
The narrator says, "I'd wake and hear the cold splintering, breaking." Cold describes the temperature, and cold itself cannot splinter or break, so we know that this line must be figurative. What does splinter? Wood splinters, especially when it is burning in a fire like those fires the father has made. Therefore, the cold that is breaking up, as a result of the fires the narrator's father made, is being compared to the wood that is breaking up in the fires themselves.