[5][a] Harmony House was announced in February 2021, following the re-release of Struble's debut album Fuzzybrain (2019) and the success of his single "Can I Call You Tonight?".

[7][8] After the release of the extended version of Dayglow's debut album, Fuzzybrain, Struble planned to embark on a sold-out headlining show in early 2020.

[9] In an interview with NME, Struble explained that the idea of Harmony House came from writing "[the] soundtrack for a sitcom that doesn't exist."

[1] Describing "Balcony", Struble explained in a social media post how he set out to create a song that sounded similarly to the music of the Cure, Broncho, and the Mario Kart video-game soundtrack.

[13][14] Driven by synths, a keyboard, and tenor saxophone, "December" describes seasonal depression, and a longing for life to get exciting again.

"[2] Originally not intended to make it onto the album's tracklist, 'Strangers" is the vulnerable, somber "emotional climax" of the record, with Struble explaining "I want people to know that I go through hard stuff too, and life is like that sometimes.

[23] Writing for Dork, Finlay Holden states "[Harmony House] push[es Struble's] production beyond the restraints of his charming yet confined origins," and that "[if]‘Fuzzybrain was the pinnacle of 2010s bedroom pop, ‘Harmony House’ is a masterful throwback to the cheese of 80s pop-rock that Dayglow somehow makes as culturally relevant and appealing as it's ever been.