Business Tips

8 Keys for Writing Email Subject Lines that Actually Work

Angelica Navarro
March 30th, 2020
3 Min Read

Email is an extremely useful tool you can leverage to communicate and engage your customers. But you might be wondering how to stand out from the crowd in their inbox. Average email open rates range from 15%-25% (and click-through rates at about 2.5%.) Could your email's open rates use a boost?

First and foremost, ensure each email campaign you send out is targeted to the right audience. An email service makes this process a snap, allowing you to send emails to the right customers at the right time. 

To get your emails opened more often, you need strong email subject lines that are both relevant to your message and attention-grabbing. If you’re not sure where to start, check out these easy tips for writing email subject lines that actually work.

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Keep them short and sweet.

Consumers are more mobile than ever. In fact, 62% of all emails are opened on a mobile device. That means your subject lines should be short enough to get your message across quickly. A good rule of thumb is to keep them under 50 characters and between 4 to 7 words if possible.

Get right to the point.

If you’re trying to sell an estimate or prompting customers to renew a membership, your subject line should make that clear. Don’t be vague about what you want your customers to do. Tell them right from the get-go.

Good examples:

  • “Your VIP membership benefits are expiring”

  • “Take 15% off a tankless water heater”

  • “Don’t forget about your home electrical project”

Avoid using spam triggers.

Most email service providers like Gmail have built-in spam detection. This means you should be mindful of what causes emails to end up in spam folders. Keep your email subject lines free of spam triggers, which include:

  • ALL CAPS (also known as yelling via email)

  • Words such as “free” or “cash” (especially if in all caps) 

  • Excessive punctuation (like exclamation marks!!!!!)

Create a sense of urgency.

If you want customers to open your emails right away, give them a good reason to do it. One of the best ways to do this is to create a sense of urgency in your email subject line. 

For example:

  • “20% off Fall tune-up” is an acceptable subject line, but it doesn’t compel immediate action. 

  • “20% off Fall tune-up ends this Friday” is more likely to spur your customers to action.

Deadlines are great at enticing customers to act quickly, so don’t be afraid to use them.

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Ask a question to incite curiosity.

Posing a question in your subject line piques customers’ interest, making them more likely to open your email to get an answer. For example, let’s say you’re running an email campaign to boost new furnace sales. If your target audience has an older heating system, you could try a subject line like, “How much is your old furnace costing you?”

Use numbers that get noticed.

Don’t underestimate the power of numbers in getting your customers’ attention. Statistics help build trust and make your emails more relevant. Numbers are also great in emails that inform or persuade customers.

Good examples:

  • “5 signs your air conditioner needs replacing”

  • “Be 30% more energy-efficient by going tankless”

Add value with helpful how-tos.

Being helpful in your emails is an effective way to get increased customer goodwill. Remember, you’re the expert, so why not offer useful, actionable information customers find valuable? Try email subject lines like:

  • “Electrical safety tips you can try in your home”

  • “Our helpful guide to choosing a home air filter” 

  • “Simple tricks that help reduce your water bill”

Giving your customers a bit of “insider information” makes them more apt to trust you and therefore, do business with you. It’s a win-win situation for you and them!

If you’re a ServiceTitan Marketing Pro user, you can also use our handy Email Subject Line grader to test your subject lines based on these best practices.


ServiceTitan Marketing Pro is an automated marketing solution built specifically for home service companies on ServiceTitan. It helps book and close more jobs by giving you the tools you need to remind your customers how important you are.

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ServiceTitan is a comprehensive software solution built specifically to help service companies streamline their operations, boost revenue, and substantially elevate the trajectory of their business. Our comprehensive, cloud-based platform is used by thousands of electrical, HVAC, plumbing, garage door, and chimney sweep shops across the country—and has increased their revenue by an average of 25% in just their first year with us.

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