Most people would agree that an envelope's purpose is safely transporting the contents from sender to recipient. But the envelope has another important job — getting opened! Magazine and catalog mailers use the covers of their mailing pieces to encourage readers to look inside, but most letter size communications don't make the same effort. If you consider envelopes as part of the overall communication strategy instead of just a utilitarian transport device, you might make a difference in the mail's success.

Companies send mail for a reason, often because they want the recipients to take a specific action, such as paying their bill or buying a product. Other mail attempts to change how someone thinks about a topic or issue (some political and non-profit mailings fall into this category). A third group might be mail that companies are required to send, such as annual privacy notices or tax forms. In any case, the front cover of a mail piece (the envelope) can affect how many mail recipients decide to examine the interior contents.

Of course, mail doesn’t always require an envelope. Newspapers, postcards, magazines, catalogs, and self-mailers travel perfectly well through the postal system without an envelope. But most of the mail we receive in my household, whether marketing mail or transactional documents, arrives enclosed in envelopes. For most mailers, distributing paper documents still relies on the act of inserting materials into window or closed-face envelopes.

If your company (or your company’s clients if you are a mail service provider) sends mail in envelopes, it’s fair to take an objective look at these critical pieces of the mailing package. Are they helping you achieve the desired result by increasing the chances the messages will be read, or are they just passive containers? Most times, envelopes are only an afterthought.

Designers can choose from many envelope design strategies meant to enhance the performance of envelopes. The internet provides plenty of advice about envelope colors, teaser text, personalization, die cuts, postage payment methods, stickers, etc. The best approach depends on the application. A design that increases open rates for one type of mail can have the opposite effect on another.

I’m not suggesting you invest in a particular envelope design or construction strategy, only that you take time to think about how your current envelopes contribute to the success of your mail pieces.


Studies show that personalization has a positive effect on direct mail campaign performance. Today, most marketers are personalizing the contents of a mailer via explicit variable data use or by altering the offers, text, and images. They use demographic, psychographic, or customer relationship information to control the contents of each mail piece. The envelope is already personalized with the recipient’s name and address. Further personalization, such as variable text or eye-catching graphics aligned with the recipient’s known interests, can make mail more enticing to the targeted recipients.

Some envelope converting machines can personalize envelopes as you make them. If you don’t make your own envelopes, then inline inkjet solutions added to inserter bases can handle envelope personalization on the fly as the machine inserts contents into the envelopes. This technique works for both window and closed-face envelopes.

Windows or Not?

Mailers have long used window envelopes to simplify the mailing process. By personalizing only the contents of a mailing, you don’t have to worry about mis-matching addressed envelopes with personalized documents. However, window envelopes convey an impression of commercial, high volume mail, which can work against you in your quest to communicate with customers and prospects.

Plain window envelopes won’t be the first thing addressees open when they retrieve their mail from the mailbox. Pieces that look more interesting will get the most attention. But that doesn’t mean you should abandon window envelopes — especially if you use windows to reveal something interesting waiting to be discovered inside. Some mailers use larger windows for this purpose. That may be an approach that works for your applications.

One of the financial institutions where I have accounts uses #10 envelopes with a window that consumes about half the space on the front of the mail piece. The bank uses these large window envelopes for both transactional documents and marketing messages. Unfortunately, they never use that space to tell me anything important — only the mailing address, return address, and logo are seen through the window. This seems like a wasted opportunity.

Always be careful about windows that allow extraneous content to show. You don’t want to interfere with USPS addressing standards, but you could reserve a portion of the window space to tease the contents inside the envelope. The bank sends me the same envelopes with the same offers every month. If the offer ever changed, I wouldn’t know it from the envelope.

Closed-faced envelopes can raise anticipation levels, especially if the envelope hints at recipient benefits to be found inside. If you are addressing closed-face envelopes with an inkjet head mounted on the inserting equipment, you can also print personalized or targeted messages on the envelope. The print technology has improved since I first looked into this technique way back in 1997. Printing high-quality, full-color graphics on the address side of an envelope is within reach of most mail service providers today.

Another factor for mailers to consider is Informed Delivery from the US Postal Service. According to the USPS, as of March 2021, 29 million users are currently subscribed to the Informed Delivery daily email. Subscribers see images of their letter mail before their carrier delivers it. Those images feature the address side of the envelope. Any messaging or graphics you’ve added will be visible, giving you an extra chance to get the addressee’s attention.

What’s the Right Approach?

Before you automatically reorder your supply of envelopes, take a step back and ask yourself if something as simple as changing the envelope will help you or your clients generate the results your mail should produce. Take the time to look at envelopes as part of the communication strategy, not simply as a container.

Mike Porter at Print/Mail Consultants helps his clients meet the challenges they encounter in document operations and creates informational content for vendors and service providers in the document industry. Follow @PMCmike on Twitter, send a connection request on LinkedIn, or contact Mike directly at

This article originally appeared in the May/June, 2021 issue of Mailing Systems Technology.