First, I would run some tests on that page using one of the following tools:
1) Google Page Speed
These two will give you an idea of why your page is slow to respond. It could be the map taking too long to call home or it could be something related to your hosting environment. Usually if its your hosting then the entire site would be very slow.
Second, analyze the reports and identify the issue. Below are some things to look out for:
1) Bad FTTB (First Time To Byte) - 9 out of 10 times this means that you need to switch hosting
2) Any pages that are over 1 MB in size. You should avoid having any of your pages blow up like that. Common causes for this are big images that have not been optimized for web or a lot of extra code (usually happens with CMS)
3) A very high number of connection requests. For a small static site I would say that anything over 30 requests is too much for a single page. For a CMS site I would say anything under 60 - 80 is a norm.
4) If you use social media buttons on your site then look out for connection requests that take a very long time. Sometimes Twitter takes forever to load over https.
In conclusion. You can identify 99% of these issues using the tools provided above and they are pretty simple to fix once you know what they are.