While the cause of a fire in an Awamoa Rd house last Thursday and the blaze in Farnham St yesterday were totally different, fire risk management officer Stuart Ide emphasised it illustrated the need for an early warning system - and smoke detectors were the simplest.
No-one was in the house yesterday, but Mr Ide said if it had smoke alarms, someone may have heard them and alerted the Fire Service sooner.
Neither fire caused any injuries.
The two occupants of the Awamoa Rd house got outside before it took hold and the woman renting the Farnham St house had spent the night with her parents.
The house was owned by partners Jason Bond and Marilyn Hoogenraad and was being rented by Ms Hoogenraad's daughter, Sarah.
They had just started renovating it on the understanding Sarah would buy it from them, and the bedroom where the fire started was the first room done.
Today, an early morning investigation at the Farnham St house will determine if the concave mirror caused the fire, which Mr Ide believes is what happened.
The mirror was on a chest of drawers in front of a window which faced east, and would have received the first of the early morning sun.
All the right conditions may have focused light like a magnifying glass on to items on the dresser, setting them alight.
A similar thing can happen with other objects, such as crystals hung to catch the light, which can focus it like a magnifying glass.
''Those sorts of things should not be hung in direct sunlight, particularly east, north and west facing windows,'' Mr Ide said.
Ms Hoogenraad said Sarah had stayed at her mother's house on Tuesday night, so was not in the house when the fire broke out.
Oamaru Chief Fire Officer Steve Couper said the call about the fire came in at 7.50am.
When the brigade arrived, the small window in the bedroom had blown out, and they were able to quickly get a hose through it to hold the fire until firefighters in breathing apparatus could get inside.
There was fire damage in the bedroom and smoke damage in the rest of the house, which was insured.
However, most of the contents, including clothes, were unusable.
Mr Ide investigated last week's Awamoa Rd house fire, which also started in a bedroom.
It was believed to have come from some sort of electrical origin, but the exact cause was still being determined.
