Rotorua Fire Brigade senior station officer Richard Anastasi said there were two people at the property at the time. One was treated for minor smoke inhalation.
There was damage to the garage and "quite a bit of smoke damage to the rest of the house", he said
Mr Anastasi was unsure if smoke alarms had been fitted.
"The occupants were lucky it didn't happen at night time. It's important to have a smoke alarm installed so people at home could be alerted sooner - we can't emphasis how important it is.
"We are more than happy to provide advice and install an alarm and carry put a fire safety check on any property for free."
Mr Anastasi said the cause of the fire was under investigation, but it wasn't being treated as suspicious.