by Adam T. Sutton, Senior Reporter

Nothing lasts forever. The products and services you sell will likely need updating, repairing or replacing some day. Customers may return for their maintenance needs, but they could turn to a competitor or forget maintenance altogether. To stack the odds in your favor, and to help customers, you can send reminder emails when customers need them most.

Housh Inc., for example, has an online branch of its business that sells indoor air quality products. The humidifiers, air cleaners and other appliances periodically need new filters or other parts to operate at peak performance. For some of Housh's websites, the replacement parts are the primary products sold.

"The [replacements] include furnace filters and humidifier water panels and related consumable products. For a healthy home environment, people need to replace and updated these on a regular basis, but they are often forgotten," says Larry Zimmer, General Manager, eCommerce, Housh.

In response, the marketers at Housh launched a three-part triggered email program to remind customers when their filters needed to be replaced. The emails were scheduled to send when customers' filters were expected to wear out. Housh launched the program on three sites:

o DiscountFurnaceFilter.com
o DiscountHumidifer.com
o HomeComfortDepot.com

The program generates about $2 for every email sent. For a recent 30-day period, 53 percent of customers the program drove to the sites made a purchase. The percentage for each of the three triggered emails:

o Email #1: 35.7%
o Email #2: 63.3%
o Email #3: 63.89%

Here are four tactics Housh's marketers used to set up the program and make it a success:

Tactic #1: Estimate when parts are replaced

The marketers first had to understand the best times to offer customers replacement filters. By timing their offers correctly, the marketers could increase the relevance of their message and increase the customers' propensity to buy.

But filters have a range of times for which they can be used. Some will last six months and others will last two years. Furthermore, some appliances come with packs of replacement filters. The challenge for Housh was to understand when each customer's filter needed to be replaced.

Rather than assuming when customers should replace their filters, the marketers measured when customers ordered replacements. They calculated each product's average reorder period and the statistical confidence level for each average.

These averages illustrated the time customers typically waited to reorder a filter. By timing triggered emails based on these averages, the marketers hoped to suggest the right product, to the right customer, at the right time.

Tactic #2. Override some of the averages

Some people use filters beyond the manufacturers' recommendations, stretching every last bit of use from them. Other people can be overly cautious and replace filters before its necessary.

Looking at the average reorder periods for Housh's filters, the marketers realized they had customers in both camps. Some filters with 365-day lifespans had average reorder rates above 400 days. At least one filter had a suggested lifespan of 700 days and an average reorder rate of 531 days.

Housh's marketers wanted to suggest a filter be replaced before it started to fail. This would help customers' appliances operate as efficiently as possible.

"While our website names describe 'discount,' our focus is really on building and maintaining a high-quality indoor air environment," Zimmer says.

With this in mind, the marketers manually adjusted the timing of the emails for some products to more closely correspond with the manufacturers' suggestions.

Tactic #3. Setup a triggered three-email series

Housh included about 120 replacement parts in the program across three websites. A countdown started each time a customer purchased one of the parts or an appliance that used it. The countdown was based on the replacement period the marketers had calculated for each product and each appliance's filter.

Once the countdown ended, Housh sent the first of three triggered emails in the program. The emails were sent from the website from which the customer purchased.

- Email #1: The reminder

The first email almost exclusively included information about the product along with some information to ease customers' anxiety about purchasing from the company.

The email's header image featured the websites' logo, a money-back-guarantee emblem, and a note that the company ships to Canada.

Other features of the first email:

o Three top navigation buttons: About us, Testimonials, Contact Us
o Large headline: "Just a reminder: It's time to reorder!"
o Large product image
o Brief product description with price
o "Reorder Now" button

After clicking the product image, description or button, customers were brought to the corresponding product page on the website.

- Email #2: The incentive

Customers who did not purchase after receiving the first email received the second email three days later. The email was nearly identical to the first, except it offered free shipping.

The email emphasized free shipping in the following areas:

o Subject line (described in tactic #4)
o Large headline: "Reorder your filter today & receive free shipping!"
o Discount code next to button

The conversion rate for visitors brought to the website from this email is 77.3 percent higher than that of the first email.

- Email #3: The last chance

Customers who still had not purchased received the third and final email five days after receiving the second. Again, it was very similar to the previous emails, but had these differences:

o Subject line emphasized "last chance" (described in tactic #4)
o Large headline: "Last chance to reorder & receive free shipping"
o Discount code next to button

The conversion rate for visitors brought to the website from this email is 79 percent higher than that of the first email and 1.4 percent higher than that of the second email.

Tactic #4. Make the emails more relevant

The most significant challenge to email marketing effectiveness is targeting recipients with highly relevant content, according to the MarketingSherpa 2011 Email Marketing Benchmark Report.

The marketers set the timing of the triggered series to make it as relevant as possible to customers' products and needs. The program also automatically added information about the products to make the emails more relevant.

Here are two examples:

- Subject lines

Each email had a customized subject line that included the customer's first name and filter or part name. The subject lines of the last two emails also mentioned the free shipping incentive. Here are examples from each email:

o Email #1: "Bill, have you checked your Lennox H/C HCF 16-10 MERV 10 Replacement Filter 16' x 25' x 5' - X6670? It looks like it's time to reorder!"

o Email #2: "Bill, get FREE Shipping on your Lennox H/C HCF 16-10 MERV 10 Replacement Filter 16' x 25' x 5' - X6670 when you reorder now!"

o Email #3: "Bill, LAST CHANCE to receive Free Shipping on your Lennox H/C HCF 16-10 MERV 10 Replacement Filter 16' x 25' x 5' - X6670!"

- Product information

Each email featured a large image of the exact product a customer needed. They also featured a short description of the product, its price, and links to read more and order the product from Housh's website. All of these details gathered inside a branded email from a company the customers knew contributed to the emails' relevance.

Useful links related to this article

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Housh, Inc. websites included in the program:

DiscountFurnaceFilter.com

DiscountHumidifers.com

HomeComfortDepot.com