AV Adds Value : Landlord's Guide : Square Foot Magazine

Investing 2 - 3% around of the purchase price into AV can significantly differentiate your property from that next door.
This can justify a higher asking price/achieve a faster sale.
Investing in AV generates returns of 5% - 10%.

This price bracket is really only worth investing in AV if it's done as part of the build phase, otherwise retro fitting cables proves too expensive.
For developers specialising in new build in the £300k bracket, significant cost savings can be made when running cables during the build phase.
For a budget of around £5k you could incorporate a 4 zone multi room audio system with an iPod that plays music in the rooms through in-ceiling speakers.
Key thing for developers is making buyers choose what they want at they want before running all the cables. It's not profitable to pre wire every property as not every buyer will want to purchase AV packs.

For higher value properties (£500k+), where a developer is looking to add value/speed up the selling process, a budget of £10k - £15k is reasonable.
This takes into account the costs of retro fitting cables and for this sort of investment the music system could extend to many more rooms, or start to incorporate video distribution around the home so you can watch DVDs or Sky in every room from a single player.
Wireless controllers allow you to walk around the home and browse through your music collection on a LCD screen.
Listen to different music in different room, or the same music across the whole house.
Also recessing a backlit plasma screen in the wall is a very cost effective way to create that "wow" factor for potential buyers.

The key thing to remember is investing in perceived benfits - focus on functionality, as opposed to going for the highest quality. It's features that sell!
A property that is already pre-wired should also be promoted as a key feature when selling. Thus, the buyer can install an extensive AV system without the headache or costs of cabling.
Make sure your estate agent can demo the system, so they can really sell it when showing round buyers. This should take no more than 10 minutes to get to grips with, provided that it's a well designed system.
Be wary of "wireless" products, as they are generally very unreliable.
Use www.CEDIA.co.uk to find a CEDIA (custom electronic design and installation association) accredited designer/ installer. This is your mark of quality. All CEDIA registered companies have to go through a strict series of exams and interviews before achieving membership status, as well as being able to demonstrate a high quality portfolio.