Find our what type of wall textures will be applied and coordinate with the wallpaper, sponge painter, or mirror contractor. Certain types of valves are better for wallpapering. Make sure the electrician has provided the proper powerVage and amperage. All the pre-planning in the world cannot accommodate each job so establish a policy ahead of time on dealing with change orders. Plan on making a few extra trips out to the job on a large home, but be encouraged that central vacs have the least amount of call-backs of all the home electronics.
Most contractors price the job per inlet plus finish equipment.
Make sure your attachments are of the highest grade possible and you will only hear from the client with referrals. Down air-duct shafts. Inside abandoned vent pipes. Inside abandoned dumbwaiters, laundry chutes, and trash chutes. Inside paneled walls.