Considering moving cash from high interest savings to an index fund, but...

I have some cash in a high interest savings account that I'm planning to use on some house projects (decent size ones, including a new kitchen, new windows, and the like), however I'm not sure whether I'll start on them this year or next. I''m thinking I should park it in some decent index fund(s) like VOO or QQQ. Really am just looking for something more than the 3.5% or so that it's generating now, with the understanding that it carries some additional risk. Am open to advice, thanks.