"I opened the garage door and saw smoke billow out, so we backed out and called the fire brigade," Mr Bronkhorst said.
Emergency services were soon on the scene, but most of the house could not be salvaged.
The Fire Service is investigating the cause.
"I know we didn't leave the stove on, we always turn it off at the wall, as we have young children," said Mr Bronkhorst, a dairy farmer who is currently on sick leave because of two hip operations recently after being crushed by a cow.
"It was my first day out the house in two weeks."
He said he was sure they will have a place to stay tonight, "as we are members of the Vineyard church and I know they will help us".
But he was worried about getting hold of the medication he is taking for his hips.
"At least we were all out and no-one was hurt."