Hi @kbroodco,
I assume you are referring to being able to see the hostnames of the other network devices since you're sharing the same subnet? You may also be sharing the same collision domain as well if your housemate's devices are also on the EAP245 in the same SSID. If you are able to click on these devices or access their file shares, etc. you should ask your housemate to properly secure their individual devices.
Simply being able to see that these devices exist on the network does not in and of itself make them insecure or necessarily mean that you can see what they are doing. Though with a packet sniffer you could potentially see some of the traffic details for other wireless devices in your collision domain.
But unless you know how to configure VLAN's and have a router/gateway which supports VLANs (which would enable you to make "more private" network partitions within the same physical network) there's really not much you can do.
Nor is there really anything to be worried about if your and his/hers devices are patched and properly secured, individually. Nearly all web traffic is SSL/TLS encrypted these days so aside from potentially being able to view the DNS requests, So it's not like you can read their email or look at their banking information.
If you really want to be sure no one can see what you are doing on your PC, you could use a 3rd party VPN service in addition. But honestly this is really overkill in a home network environment.
-Jonathan