New 2013 MacBook Air connects to routers everywhere but home, older MacBooks connect fine
Lets try to manually connect to your Network

In Terminal copy paste following:

To turn On MBA wifi

networksetup -setairportpower en0 on


Find networks (displays the list of networks

/System/Library/PrivateFrameworks/Apple80211.framework/Versions/A/Resources/airport scan


Connect

networksetup -setairportnetwork en0 WIFI_SSID_I_WANT_TO_JOIN WIFI_PASSWORD


You can skip 1 and 2 if you already know the information