They get all the packets from your house at the local switch. That they have backdoor access to the search engines is lagniappe and only makes things faster and easier for them.
They have all your searches too. From any engine you choose. It just takes them a millisecond longer to put them together.
Ideally, it would require a browser that can encrypt the search request (such as: https://www.eff.org/https-everywhere) or anonymize you as the source (see: https://www.torproject.org/)
Plus a search server that would deliver the results in a discreet form (ixQuick and perhaps startpage and duck duck go) through a proxy server setup, as explained here: http://lifehacker.com/5763170/how-to-secure-and-encrypt-your-web-browsing-on-public-networks-with-hamachi-and-privoxy
A huge pain.