There's nothing scientific about the a priori belief that everything spiritual is not real. It's a deep bias in science that comes from its origins. In its early days, in order to exist beside the church, it had to define itself as separate from the church, and focus on the physical world. To the church, the spiritual. To science, the physical. It carved out its place and while very few know the origin of this built-in belief, it's still almost universally accepted.
Ghosts are real. They have been measured. Sounds, voices, pictures, conversations back and forth with the living. To automatically ascribe these things to alternate sources shows the bias at work, the built-in unshakable belief that they do NOT exist. Someone truly neutral would see the evidence and if he was unable to find a different way to explain it, would settle on the idea that they are real.
The best tool for detecting ghosts is the human body, which can feel their energy. But that's not easily measured. Direct methods include EVP, photography, video (infrared, heat, wide-spectrum), and the "spirit box". Indirect methods include measuring EM spikes, measuring the room's temperature fluctuations, though these don't say much on their own. I've thought the visual equivalent of EVP could probably catch something - have a TV with static lighting the room, and a camera filming the room, and maybe the static as well. The Travel Channel's Ghost Adventures seems to be the real thing. You can see much of this at work there.
You will have trouble proving that your specific house ISNT haunted. Ghosts are not ever-present, and don't come on command. Interacting with the physical world by taking form or producing voices takes a lot of energy, and it often takes very specific conditions for this to happen. Ghosts can drain batteries and use ambient energy sources (light, sound, electrical power) to manifest, so providing this could help a manifestation happen.