To complicate matters for firefighters, an oil tank spilled during the fire, fueling the flames.
The three injured firefighters will be okay. The heater repair man is at Abington Hospital.
40 firefighters were called out around 11:05 a.m. Friday.
Homeowner Cathy Yost got out of the home just fine.
The repair man, who works for "Self Heating and Cooling" of Fort Washington was found outside gasping for air, and officials say he appears to have some facial burns.
Three firemen received electric shocks when they arrived at the blaze which badly damaged the home.
