When I was kid, I tried to turn every House Finch we had in Indiana into a Purple Finch.
Trying to figure out if one is a little bit more raspberry red from another was the id of choice as the local bird ladies told me. I was also trying to see how far down the pink coloration went on the body. The above bird is clearly a male House Finch.
But now that I live some place where we get Purple Finches regularly, there is no question on how to tell them apart. The shape is different for one thing. But even if you are new to birding and have a tough time seeing that, the easiest way to tell them apart is to look at the flanks. Adult male Purple Finches lack the streaking on the sides that House Finches have on their bodies. The can have some around the rump but not nearly as much as a house finch. Immature males in traditional plumage will have the streaking (Like the bird in the featured image with this post. That is a young male growing in his adult plumage and still showing some of the streaking). But if you look at that robust head and how the eyebrow is lighter than the rest of his head, he’s a Purple Finch.
Keep an eye on those sunflower feeders and see what you can find pink finch wise.