The 33-year-old pleaded guilty last November to murdering his wife, Rebecca Chamberlain, 35, and neighbour Tisha Lowry, 28, and it was also revealed he had sex with both of them after they were dead.
Justice Lester Chisholm sentenced Somerville to life in prison with a minimum non-parole period of 23 years at the High Court in Christchurch today.
There was no apology, no remorse and no empathy from Somerville, he said.
Ms Lowry was killed in September 2008 after she disappeared while out walking, and Ms Chamberlain was killed in August last year.
Police found the women's bodies under the semi-detached Wainoni house in September.
The house, dubbed the "house of horrors", was demolished after being the subject of repeated arson attacks.
