Where I live, we have winter snow for at least five months. I cannot say that I have noticed that issue where I live. houses here feel colder in the winter because it is colder outside. People tend to not pile snow up against their homes because they don’t want extra water in the spring to intrude into the basement. The homes where I live are typically insulated well enough that snow piled up would not really affect the temperatures of a home. I suppose that snow piled up against the house would block solar heat gain during the daytime.