I’m installing a central vacuum in another house I just purchased. I’m not sure what I’ll do with it but a little improvement should make it a good investment. Rather than use a factory power unit, I’ve decided to use 4 shop vacuum units in a series-parallel arrangement. The highest specifications I could find re: a factory unit is a suction specified as 125 inches of water, and airflow of about 250cfm. The best of the shop vacuum specifications was about 90 inches of water and 150cfm of airflow. Although money is not an issue, savings would be about $800.00 using the 4 shop vacuums ($450.00 vs. $1250.00). The reason for the multiple units is to increase suction and air flow to exceed the factory unit. Suction increase would be achieved by 2 units in series and to increase air flow, they will be connected in parallel with another 2 units in series. Shop vacuums do not use the debris-laden air for cooling but use fans circulating surrounding air. Any flaws in above? I want to use minimal filtration in the system, but some is necessary, as particulates will abrade the vacuum fans. To use only limited filtering, I plan to draw from a baffled enclosure wherein the baffles and volume of the enclosure will sufficiently slow air speed to allow larger particles to drop out. Final exhaust will be outside the house. The enclosure will be a 50-gallon trash container; the lid replaced by the baffle components and the input/output ports. I’d like to have about a 30-gallon debris collection volume. I would appreciate suggestions for the baffle arrangement. Why am I re-inventing the wheel? I have no idea. When finished, I’ll probably have spent twice as much money compared to a professionally installed system. Retirement is dangerous. My wife thinks that anything that gets me out of the house is a good idea.