Firefighters were alerted to the fire in Park Road West on Thursday evening, after a 999 call reported an explosion at a property.
Around 20 per cent of the house was involved in the fire, after the immersion boiler had exploded in a rear first floor bedroom.
Crews – from Wolverhampton, Fallings Park, Bilston and Tettenhall stations – rushed to the scene in the West Park area shortly before 7pm on Thursday.
A spokesman from West Midlands Fire Service said: "At 6.58pm we received a 999 call reporting there had been an explosion at a property in Park Road West. The initial call said it had happened in the rear bedroom of a house.
"The house was full of smoke. Four fire engines were sent to the scene, with a total of 20 firefighters. The first crew arrived within three minutes.
"The incident involved an immersion boiler which had exploded in the rear bedroom on the first floor of a semi-detached house.
"Approximately 20 per cent of the house was involved in the fire.
"The last crew left the scene at 9.26pm."
West Midlands Fire Service also confirmed the incident on Twitter.
They said: "Crews are in attendance at a property fire in West Park, Wolverhampton involving an immersion boiler which has exploded in rear first floor bedroom of a semi-detached house.
"Twenty per cent of the building involved. Four pumps in attendance and crews ventilating due to smoke logging in property."