@Tiorlan I bought vol. 1 and can confirm that is the case.
Just in case there are people who don't get the wordplay in their names and in the title, 『思い』(feelings)『重い』(heavy) and『面井』(her last name) are all read as "omoi". Her whole family has extremely "heavy-hearted feelings" that they express in over-the-top ways.
In contrast, Karuizawa's "karui" is actually written with the kanji for "light" (『軽い』), but funny enough, in his case it doesn't quite fit because his feelings for her are anything but light.