Looks like the Dursleys have two fireplaces in their home.
First one in the living room:
But Dudley didn't seem able to speak. Hands still clamped over his buttocks, he waddled as fast as he could into the kitchen. Harry hurried into the living room.
Loud bangings and scrapings were coming from behind the Dursleys' boarded-up fireplace, which had a fake coal fire plugged in front of it.
Harry Potter and the Goblet of Fire, chapter 4
And one in the kitchen:
WHOOSH. With a clattering, a whirring of wings and a soft fall of dust, a fourth owl came shooting out of the kitchen fireplace.
Harry Potter and the Order of the Phoenix, chapter 2
Why do they need them? Fireplaces are pretty obsolete and costly compared to other heating methods. The one in the living room is boarded and converted to an electric heater but the other one in the kitchen looks like it is used. It is open and the owl could fly via the chimney in the house.
As a bonus question (sorry but it is a bit silly anyway). In the Bulgarian translation the word "dust" from the second quote is translated as "ash" which makes even little sense since it is an ultra-hot summer and lighting up a fire place sounds like an extremely stupid idea.
Is this simply a translation error?