According to Google official blog, websites with SSL certificate installed may improve SEO ranking.
From Google blog –
We’ve also seen more and more webmasters adopting HTTPS (also known as HTTP over TLS, or Transport Layer Security), on their website, which is encouraging.
For these reasons, over the past few months we’ve been running tests taking into account whether sites use secure, encrypted connections as a signal in our search ranking algorithms. We’ve seen positive results, so we’re starting to use HTTPS as a ranking signal. For now it’s only a very lightweight signal — affecting fewer than 1% of global queries, and carrying less weight than other signals such as high-quality content — while we give webmasters time to switch to HTTPS. But over time, we may decide to strengthen it, because we’d like to encourage all website owners to switch from HTTP to HTTPS to keep everyone safe on the web.
For full details, please refer to
http://googlewebmastercentral.blogspot.com/2014/08/https-as-ranking-signal.html
Customer may consider to install SSL onto your website (it involves additional fee for SSL certificate and dedicated IP. For details, please feel free to contact us)
SSL certificate can be classified as standard (domain-validated, organization-validated), and EV (extended-validation)
Domain-validated is the simplest SSL, it is a cost-effective to enjoy HTTPS, and generally needs within 1 – 2 working day to process
EV SSL (extended validation SSL) requires thorough validation on applicant organization, and involves more cost. Nevertheless, when issued and installed, the visitors’ URL bar of the browser becomes green (a.k.a. green bar). The SSL imprints applicant organization name, and generally have more trust value to website visitors. For example, our main website (https://www.website-solution.net) deployed an active extended-validation (EV) SSL.
The website (https://kb.website-solution.net) you are currently viewing is also protected domain-validated SSL encrypted connection.