Icons are added using below CSS:

.property_listing.property_unit_type2 .property_listing_details .infobath_unit_type2:before{
    content: "\f043";
    font: normal normal normal 14px/1 FontAwesome;
    margin-right: 7px;
}

.property_listing.property_unit_type2 .property_listing_details  .infosize_unit_type2:before{
    content: "\f278";
    font: normal normal normal 14px/1 FontAwesome;
    margin-right: 7px;
}

.property_listing.property_unit_type2 .property_listing_details  .infogarage_unit_type2:before{
    content: "\f1b9";
    font: normal normal normal 14px/1 FontAwesome;
    margin-right: 7px;
}

.property_listing.property_unit_type2 .property_listing_details .inforoom_unit_type2:before{
    content: "\f236";
    font: normal normal normal 14px/1 FontAwesome;
    margin-right: 7px;
}

In order to achieve above must edit the content for the css you wish to change the icon and replace it with other content icons from Fontawesome: https://fontawesome.com/icons?d=gallery&m=free