A Kapiti Coast woman suffered permanent brain damage after gas poisoning from an incorrectly installed heater, a court has been told.
Amanda Pickard and her son are seeking $1.6 million in damages against the heater's installer Chas Ambrose and distributor Rinnai New Zealand.
The Pickard family claims the installation of the wrong flue system on the Cannon Deluxe gas heater poured the toxic gas carbon monoxide into the lounge room for three years from 1998.
The problem was not discovered until Ms Pickard complained of an overpowering gas smell in her lounge.
In his opening address on Tuesday, the family's lawyer Mike Lloyd argued the poisoning was caused by a series of mistakes by Chas Ambrose and the use of a fluing system at the back not suited to the heater.
The court was told Ms Pickard has suffered a number of serious health effects from prolonged exposure to the gas.
She now has eyesight problems, memory loss, panic attacks and a general loss of brain function.
The court was told she once fell unconscious for about 30 minutes while sitting in front of the heater studying.
Mr Lloyd told the court Rinnai bears large part of responsibility because after it sold the heater it gave wrong advice and incorrect fitting for the flue.