My site's template has multiple H1 tags. Is this a problem? John Mueller answers this question on Google's SEO Snippets video series.
An H1 element is commonly used to mark up a heading on a page. There's something to be said for having a single, clear topic of a page, right? So how critical is it to have just one of these on a page? The answer is short and easy.
It's not a problem.
With HTML5, it's common to have separate H1 elements for different parts of a page. If you use an HTML5 template, there's a chance your pages will correctly use multiple H1 headings automatically.
That said, regardless of whether you use HTML5 or not, having multiple H1 elements on a page is fine. Semantically marking up your page's content to let search engines know how it fits together is always a good idea.
If you end up using multiple headings on a page, that's fine.