We recently evaluated 35 theme candidates. All are available as free downloads from the WordPress theme repository. They came to our attention via email newsletters. Some are new and others are older but still popular. The alphabetical list is at the bottom of this page.
Here we report some theme trends that affect website speed and how to evaluate what is important.
Remember, our goal is a two-second, home-page load time using WordPress. The lighter the theme overhead the more headroom we have in our performance budget for adding things like images, forms, and other features.
There are certain cues and clues that help us evaluate a theme for speed potential (fast page load) – without installing it first. The download package size is number one on our list. Any theme download that is under 1M (zipped) usually is a sure bet for speed. But larger than that compressed file size doesn’t always mean a speed failure. You have to dig deeper by downloading the package and examining the contents. The 1M package size is a quick-and-dirty selection method.
A compressed theme package may contain many resources – or sometimes non-features. When we say non-features, we refer to fluffy bloat intended to deceptively entice website owners. Theme authors include these things to make the theme appear “feature rich.” But most features have a speed price.
Modern WordPress Speed Traps
When evaluating themes for speed, you need to consider the following:
- Google Fonts (or worse the heavier Typekit) will slow down a website. It’s now rare to see a theme using fast-loading system fonts. Die-hards argue that most Google Fonts are now present in all browser cache. There is no way to prove this with present online testing tools.
- Fontawesome icon font – or an equivalent such as genericons or glyphicons. Icons are a popular inclusion. The downside is they load universally on all WordPress pages and posts whether the icons are used or not. How much this slows down a site depends on variables. We feel icon fonts are justified if you leverage them in your page design. But usually, it’s better to dequeue the font in the WordPress functions.php file and simply use icon PNG image files. If you remove the font files from your server using FTP or C-panel, you will end up slowing down the site even worse with 404 errors. Fontawesome can slow down a site by 500 milliseconds. But how bad it really is depends. More typically, you’ll see delays of 100 to 200 milliseconds. There may be some improvement by using Better Font Awesome plugin and loading from their external CDN. We’ve played with this in tests and it has some potential for time-saving parallel loading.
- Sliders are common additions now. When they are built into a theme, they may universally slow down all pages – even when they are only used on the Home page. How bad this delay is depends upon the slider. But for example, Nivoslider slows down all site pages by minimum of 200 milliseconds – even when no slider is present. The most popular in the 35-theme evaluation was Nivoslider (5 instances). Other sliders included: bxslider, OwlCarousel, Flexslider, Sldr, lightslider, and few custom ones. 19 of the 35 themes used sliders – that’s 54 percent. Over half. Sometimes, a better strategy is adding a standalone slider plugin and then selectively activating the plugin only on pages where it’s needed. The best plugin to do this is Plugin Logic.
- Every theme includes a screenshot that serves as an icon in the WordPress theme control panel. These are rarely optimized images. In this evaluation, they vary from 100k to 2.5M Jpeg file sizes. The typical size is about 600k. This extra theme package weight doesn’t slow down the theme. But it’s an indicator of the theme author’s attention to speed details. A bloated screenshsot is simply benign, but wasteful, overkill.
- It’s common for many themes to include sample or demo images. Like screenshots, these are rarely optimized images. 16 of our themes included header or slider images for easy setup. But they are extra baggage in the package. Worst case we had one theme with over 5M of Jpegs. But more typically, they were around 200k to 500k. These images are not intended to be used. They will be slow loading.
- Theme packages may include language translations. These can add from 100k to 600k. But only 6 of our samples had these files. They don’t slow down a site. They just increase the package size.
Here’s the alphabetical list of themes evaluated: accelerate, accesspress-basic, activello, amazing-blog, awaken, awesome, bizgrowth, blogim, canape, coral-light, dellow, enigma, faceblog, flatter, futura, grow, hemingway, hueman, kotha, make, nisarg, perfetta, pingraphy, quidus, rams, responsive-brix, revive, simona, sixteen, splendor, tora, tracks, travel-eye, ultrabootstrap, and zerif-lite.
Excel spreadsheet analysis. Download >
The final proof is installing the themes and doing benchmarks. But, as noted above, there are things that can streamline our selection process before installation.
Fatness and popularity: Site owners prefer bloat.
The pressure to inflate theme package sizes is almost irresistible for theme authors. This is evidenced by the popularity of two examples: Zerif-lite (2.7M zip) 100,000 installs and Hueman (2.1M zip) 80,000 installs. And the incredible, 7M-download Enigma theme with 30,000 installs. Most themes are lucky if they get 10,000 installs. The fatter the more popular.
So if a theme is popular with the most installs, you can bet it’s a slow loading theme.