Proper furnace duct installation

It takes work to move it upward against gravity or to push it any direction against friction. And that brings us to…. If you take that same fan and blow the air into a cardboard tube, it has to work against the pressure that builds up in that space. The more you reduce the size of that tube or make it longer or turn the air with it, the more static pressure builds up.

And the more the air flow is reduced. One is friction. As the air moves through a duct, it interacts with the surfaces. The smoother that inner surface is, the better it is for air flow. The rougher the surface, the more it slows down the air. The second factor is turbulence. This generally arises when you move air through fittings, or when you turn the air. When air comes out of the air handler, several things happen to it.

It gets sent to the various rooms in the house. As it travels through a trunk-and-branch duct system, the quantity keeps diminishing because some of it gets diverted down each branch on the way to the end. Each section of duct, each fitting, each turn of the air adds resistance to that air flow because of friction and turbulence. Grilles and registers, filters, and balancing dampers also add resistance. That resistance results in decreases in the static pressure, or pressure drops.

So, we begin at the blower with a high pressure. By the time the air comes out of the supply vents, that pressure has dropped to zero relative to room pressure. You can get to the other articles in the series with the links below. Duct Design 2 — Available Static Pressure. Duct Design 3 — Total Effective Length. Duct Design 4 — Calculating Friction Rate. Duct Design 5 — Sizing the Ducts. You pay the same price you would pay normally, but Energy Vanguard makes a small commission if you buy after using the link.

The presentation style in The presentation style in this article is very easy to follow. It simplifies complex information for the layperson or, in my case, the architect.

Not that it matters for your Not that it matters for your discussions, but I thought the density of air at STP was 0. That is correct for dry air, but real air does have water vapor in it. Have proper burner operation and proper draft. Procedures to Design and Install an Air Distribution System The following steps should be followed in the design and installation of the HVAC system to ensure efficiency and comfort for details, see Appendix 1 : Determine room-by-room loads and air-flows using ACCA Manual J calculation procedures or substantially equivalent.

Layout duct system on floor plan, accounting for the direction of joists, roof hips, fire-walls, and other potential obstructions. Determine register locations and types, duct lengths, and connections required to produce layout given construction constraints.

Charge the system appropriately, and verify charge with the evaporator superheat method or subcooling method or substantially equivalent. Check for proper furnace burner operation and fire-box drafting.

Charles, MO or surrounding areas? Contact us online or give us a call at today! What happens if a furnace filter faces the wrong direction? How can you ensure your filter faces the right way?

Steve was very professional and informative about what they offered. Micheal W. Technician Steve came out on a service call to my heat not working. Showed him what the furnace was doing and with that information was able to have it fixed with in under an hour. My house is now warm again and we can sleep in peace Knowing Jerry Kelly has my back. Mary Margely G.