Native File Formats and PDFs

This page describes the requirements for linking to non-HTML resources, such as PDFs and Word, Excel, and PowerPoint documents and best practices for optimizing Word, Excel, and PowerPoint files for search engines.

When linking to native files, remember that links to these types of files will not be accessible to site visitors who do not have the native software program or plugin on their system.


These standards are required for all EERE Web sites.

Linking to PDFs, ZIPs, and Microsoft Office Files

When you link to these file types, you should include a link to the file and the appropriate icon for that file type:

  • Adobe Reader (.pdf) PDF
  • ZIP files (.zip) Compressed File
  • Word (.doc, .docx) Microsoft Word
  • Excel (.xls, .xlsx) Microsoft Excel
  • PowerPoint (.ppt, .pptx) Microsoft PowerPoint

The link should be descriptive. Use either the name of the file or a phrase that clearly describes what the file is. For example:

See the 20% Wind by 2020 reportPDF.

See the full list of awardeesMicrosoft Word.

Coding Icons for Sites in OpenText or Hosted at NREL

If your site is in the OpenText Content Management System or at NREL, the icons will be added automatically when you link to any of the file types above. Code a direct link to the file. The icon will appear when the page is published to development or live servers.

Coding Icons for Sites not in OpenText or Hosted at NREL

If your site is not in the OpenText Content Management System or at NREL, you will need to code the icons manually.

A link to a PDF should be coded as follows:
<a href="/somepdf.pdf">Wind by 2020 report<img src="/images/icon_pdf.gif" width="13" height="14" class="arrowicon" alt="PDF"></a>

Include the icon inside the link so it can be read by screen readers. Do not include a space between the title and the image icon—a small amount of padding will be inserted automatically by the class "arrowicon."

Links to the icons and their alt text should be coded as follows:

  • <img src="/images/icon_pdf.gif" originalAttribute="src" originalPath=""/images/icon_pdf.gif"" width="13" height="14" class="arrowicon" alt="PDF">
  • <img src="/images/icon_zip.gif" originalAttribute="src" originalPath=""/images/icon_zip.gif"" width="13" height="14" class="arrowicon" alt="Compressed File">
  • <img src="/images/icon_word.gif" originalAttribute="src" originalPath=""/images/icon_word.gif"" width="13" height="14" class="arrowicon" alt="Microsoft Word">
  • <img src="/images/icon_excel.gif" originalAttribute="src" originalPath=""/images/icon_excel.gif"" width="13" height="14" class="arrowicon" alt="Microsoft Excel">
  • <img src="/images/icon_powerpoint.gif" originalAttribute="src" originalPath=""/images/icon_powerpoint.gif"" width="13" height="14" class="arrowicon" alt="Microsoft PowerPoint">

Linking to Other Native File Types

For these files, link to the file and the file type and size. Use the following format:

Name of file (FILETYPE SIZE)

The link should be descriptive. Use either the name of the file or a descriptive phrase that describes it. For example:

Download the full version of Energy Plus (EXE 3 MB).

For multimedia files, include a link to download the plugin after the link. See the multimedia standards for more information.

File size should be listed in KB, MB, or GB. Round files sized in KB up to the next full number. Round files sized in MB or GB up to the next tenth of a decimal.

Do not include the decimal if it is a whole number. For example, list a file as 3 MB, not 3.0 MB.


Keep native file format documents in a /docs/ sub-directory. For PDFs, see the PDF Standards.

Best Practices

Following these best practices will result in better search results for native files.

Title Fields

Adding title metadata to native files creates more meaningful search result captions in EERE's search engine and commercial search engines such as Google, Yahoo, and Bing. For every document, be sure the title field is filled in accurately.

Subject Fields

Adding subject metadata to native files creates more meaningful search summaries in EERE's search engine. For every document, be sure the subject field contains a summarized description of the content, not to exceed 200 characters.

For more information on optimizing native files for search engines, contact the EERE Search Specialist.

Related Information