So, the logic would look something like this (the ID would match that of the search form):
global $searchandfilter;
$sf_current_query = $searchandfilter->get(1234)->current_query();
if ((!$sf_current_query->is_filtered())&&($sf_current_query->get_search_term()=="")) {
// the code to display the 8-10 default houses
} else {
// the normal results loop code here
}
But, I am not sure Avada uses traditional templates, so this may be difficult to code. In the past, other Avada users have needed to use a third party grid plugin, such as this method (which does not offer the option to do as you want in this case):
https://searchandfilter.com/documentation/3rd-party/post-grid/