We are having AC installed in our new house and as a result we currently have two large ducts running against the wall of our dining room. The goal is to eventually have those concealed behind some dry wall (losing a small corner section of our dining room). But I'm thinking before doing that this would be a good opportunity to drop some cable from the upper floor (where I don't believe we have any jacks for cable TV) to the basement. We have cable internet and I intend to have my office of the upper floor, so I need internet access up there

Is this a good idea? The ducts end in a closest on the upper floor and I should (I think) be able to route cable to the master bedroom and the other upstairs bedroom (that I was planning on making my office). Should I use a conduit? If yes, what type? Is it a problem if it runs too close to the ducts? Should I run an ethernet cable instead (or as well) and keep the cable modem in the basement? If so, where would be the best place for the wireless router?

We will be transferring our cable service from our current residence to the new house when we move in and I strongly suspect the cable installer won't be too interested in running cable upstairs.

  • 1
    Totally worthwhile to also run a couple Cat5e or Cat6 cables as well, particularly to your office. Whether you put modem/router up there or elsewhere, you can get wired connections to other areas of the house, plus those cables/jacks can be used as telephone lines as well.
    – gregmac
    Aug 13, 2014 at 19:28

2 Answers 2


That is a great idea. If there is space, run two large (1.5+ inch) conduits to make running new network cables, stereo audio, HDMI, and coax in the future easier. Take care to minimize the number of bends in the conduit for easier use, and use large radius elbows if any elbow is needed.

Ducts and low voltage signals can be as close as you want. In some commercial installations, cables are placed inside air ducts when it is the only access.

  • What type of conduit? Metal or plastic? Or does it really matter? Aug 13, 2014 at 18:48
  • 2
    for low voltage, it doesn't matter. Since you said you wanted your home office upstairs you might want to run some network cables as well (cat6). Wireless is great but running hardware connections to high demand areas (TV's, computer stations or second/third wireless access points) is always worth it if you can.
    – diceless
    Aug 13, 2014 at 19:02
  • Tip: If you add conduit, then run any cables OUTSIDE of the conduit, leaving the conduit empty. Rationale: If you are adding additional cables, it's easier to run through empty conduit. If you are replacing, then it means the current wires are obsolete anyway so there's no need to take them out.
    – gregmac
    Aug 13, 2014 at 19:32

You are right. Cable installers are complete morons who know zero about carpentry and will do whatever is easiest for them.

The ideal is to run thin-wall EMT conduit from the basement to the attic. The conduit should be held to studs or some other firm support, like a joist. Once the cable is in the attic, it is easy to drop it into upstairs rooms. Make sure the data conduit is marked "video" or "data only" or something like that.

Do not put data cables in the same conduit with electrical wires.

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