An HRV would cost less to run and do a more thorough job. It will give you fresh air as well as lower humidity. My house is somewhat tight and when the windows are closed my bedroom gets really stale by morning. Especially if I have company. A dehumidifier won't help that. One of my green building guru friends lives in a pretty tight house with no HRV and he once said to me "if we sleep with the bedroom door closed we wake up around 3:00 feeling partially dead". But, then again, I've been wrong before. Maybe dehumidifiers can cure death!