Four fire engines and around 25 firefighters tackled a fire at a detached house on The Common in Stanmore.
A small part of a solar-powered battery storage on the ground floor was damaged by the fire. There were no reports of any injuries.
The fire is believed to have been accidental and caused by an electrical fault.
The Brigade was called at 0453 and the incident was over for firefighters at 0711. Firefighters from Stanmore, Mill Hill and Wembley fire stations attended the scene.