When Mauricio Lopez came to the United States 20 years ago from El Salvador to live with his mom, he had a green card, but no high school degree. He was 18 years old and did not speak English. So, his job possibilities were limited. For a time, he served as a restaurant cook.

　　He learned English while working in a building supplies store. He also became a U.S. citizen. A man who often came to the store owned an HVAC company. HVAC companies deal with the heating and cooling systems for buildings.

　　The man asked Lopez to come work for him. He asked over and over again for three years.

　　"But I was, at that time, again I was afraid, because I didn't know anything about no electricity, or anything related to heating and cooling, you know, job."

　　The man said he would pay Lopez to learn the job, but the wages during training would be low. The training to get a certificate as an HVAC technician would take seven months.

　　"You start thinking about bills and all the responsibilities, but he's like, 'once you learn, everything's going to be different, you know'?"

　　Six years ago, the man made one last offer, and Lopez, with support from his future wife, decided to go for it.

　　Within a year, Lopez had his HVAC certificate and became a senior technician. His new employer was proved right, everything for Lopez was different.

　　"So they gave me the certificate with them, and then, life changed, my life changed real. So, I am happy that I took the opportunity that he gave me."

　　Lopez works for a different company now, and says he is "blessed." He makes two times the amount of money he made before, and loves his work. He is now married and has a baby girl.

　　Lopez is just the kind of worker described in a new report from the Strada Education Network, Lumina Foundation and Gallup. The report says that American adults who hold certificates and certifications, but no college degree, report better employment and lives than those without certificates. Lumina says that five percent of individuals without a college degree have a certificate.

　　The report is based on the Strada-Gallup Education Consumer Survey of U.S. adults. The survey looked at Americans' educational experiences and attitudes. It involved almost 64,000 participants, ages 25 to 64. No one in the group had a college degree nor were any in college. All were working.

　　It found that adults without a college degree, who have a certificate or certification, have higher full-time employment rates than others with no credentials. The report says they have higher yearly wages. It also says they believe their education path was valuable, and would advise others to follow.

　　Dave Clayton is a vice president with the Strada Education Network.

　　"What was unique in this research is actually asking people directly about their experiences, and learning that they feel that they are more attractive job candidates, those who have a certificate or certification, and also hearing in their own words, their sense that they would recommend their path to others like them."

　　Clayton says the research found that there is more than just economic value to getting a certificate or certification.

　　"So the individuals not only are getting the economic and wage benefits, that are documented in other places, but they also have this sense of it was a valuable experience for them, in their lives."

　　HVAC is just one of many industries for which there are certification programs. There are all kinds of health care industry certificates, for example. A CPR certificate means you have learned how to perform cardio-pulmonary resuscitation. A phlebotomy certificate can help you get a hospital job drawing patients' blood for testing. There are also certificates for work in transportation, like CDLs, or commercial driver's license.

　　Clayton says it is interesting to see how the income benefits are very different, depending on the work the person chooses.

　　"So security and protective services, architecture, engineering, construction, mining, certificates for people in those fields, they report having higher incomes if they have certificates and certifications."

　　Certificates in education, training, library, or office or administrative and support worker jobs do not earn as much.

　　Also, the extra income enjoyed by non-degree adults who have certificates is "considerably larger" for men than women, across all kinds of jobs.

　　But whether a certificate brings small or large wage increases, Lopez says he earns a lot from helping his customers.

　　"You go there and tell them, look, don't worry, I'm going to fix it, and then we walk out of their house and you see their smile on their faces and it's like 'Wow.' It's awesome! It feels good!"

　　Sometimes, it is not just about the money.

　　I'm Anne Ball.

　　Anne Ball reported and wrote this story for VOA Learning English. Caty Weaver was the editor.

　　What do you think of this story? Do you have a certification or certificate? Write to us in the comments section below. We want to hear from you!