The house was destroyed and Miss Blumenthal's cat was killed. She lost $30,000 worth of items in the fire.
The board in its decision said a parole assessment report indicated Ashton had been a model prisoner, which had also been confirmed by his Corrections officer. Ashton had accepted that this was an extreme situation "occasioned by his bad decision, having consumed alcohol, which he does not offer as excuses".
Ashton had acknowledged what he had done was serious and unforgivable, the Parole Board said.
He also acknowledged the sentiments expressed in the victim impact statement which he had seen but said he did not want to have any contact with Miss Blumenthal.
Ashton had had counselling and the plan had been for him to take part in the Dependency Treatment Unit Programme at the prison, but he was unlikely to get entry to the programme before the sentence end date next year.
The Parole Board said it would release Ashton as the risk of him re-offending was low. His behaviour in prison had been excellent, he'd had a minimum security classification while in prison and very good family support.
"All of those factors indicate to us that despite the time left on his sentence ... and also in consideration of conditions which he will be obliged to meet, that he is not an undue risk to the community should he be released at this time."
The conditions of his parole include not coming to Rotorua unless approved by his probation officer, not to contact Miss Blumenthal, to undertake counselling including addressing alcohol-related issues and not to possess or consume alcohol until February 3 next year.
He is also to live at an address, which has not been made public, and not to move from there unless approved by his probation officer.
Miss Blumenthal said she had been made aware of the Parole Board hearing and wrote to the board asking them not to release Ashton.
She did not learn of Ashton had been freed from jail until a week after his release.
"I was a bit gutted. I'm very disappointed in the judicial system. I feel like I have been ignored. It feels like the victim is being punished."
She said the parole conditions only applied until October next year and Ashton was still allowed to come to Rotorua as long he had permission from his probation officer. She understood he was living in a region close to Rotorua.
Miss Blumenthal said she never wanted to see Ashton again and did not know what she would do if she did.
"As far as I'm concerned he doesn't exist."