The page seems to load really quickly and renders well in the big 3 browsers. Not sure what type of feedback you need, feel free to ignore me if this isn't what you meant.....but here are some observations:
1. Mind the spacing on your content boxes. Be consistent on the vertical and horizontal spacing you use and use the same spacing each time in a region. So, if you look under the heading you have that says "rocket stove mass heater", you've used three different vertical spacing sizes. Choose one vertical space size and use just that as a style point for that region. By testing different spacing, your eye will generally tell you which one looks best. It may be that you are applying a different set of stylesheets in your sandbox, so this may not be an issue.
2. The "rocket stove mass heater" header appears to be inconsistent with every other instance of the term, which seems to say "rocket mass heater". I am picking nits here.
3. Be consistent in your bulleted and numbered item lists. You can begin each list item with a capitalized letter or a lower case letter as a style point, but you shouldn't mix the two. Also, the list items have the same line spacing between items as they do between lines in an item, causing them to look like they run together
4. Where you have a content box header that is pushing the width of the box, consider rewriting the header to be more concise so that the text doesn't look mushed in there. Since you're using a max width width template, you can decide on a minimum width that looks pleasing and apply that to all of that type of header.
5. The article is long, a table of contents with section links would help returning visitors find the parts they want to review and give new visitors a reason to read the whole thing!
Cassie, I like Ondine's table of contents suggestion. The article is well written and with the (awesome) graphics and short videos, one really gets a feel for what a rocket mass heater is all about. I only have one complaint. I am reading on a kindle and the font is quite small (smaller than on many other web pages). I can switch to reading view for the main bulk of the article, but at the bottom, as videos do not follow into that view, it makes it difficult to understand. Very nice over all! 👏. Cris