![]() They also are made so that joints have a tighter seal than do those of the rectangular variety. Spiral ducts, because of their inherent design, have no seams on their length to leak air. It also might mean that a variable speed fan is running at its faster speed most or all of the time. More Energy Use – Higher Utility Bills: What is your normal response to low air flow in your HVAC system? Crank it up! Either turn the thermostat down in summer or up in winter to compensate for the poor efficiency. That means there may be hot spots and cold spots (depending on the season). It causes lower pressure throughout the system, which means less air coming through the registers in your home. Hot/Cold Spots: Loss of air in an HVAC system could be likened to a leak in our vascular system. Due to their increased weight and shape, there will usually be more sections than when spiral is used, and therefore, more air is lost with rectangular ductwork. In addition, air is also lost at every joint between sections, known as a “transverse slip connection”. There is a longitudinal “lock” seam that runs the entire length of each duct section, as was mentioned above. The main way that air is lost in rectangular ductwork is through the seams and joints. That’s a 50% reduction over the best outcome you can expect with rectangular ducts! Because it is practically airtight, and with many options for coupling and sealing the end-to-end joints, spiral ducts can often have as little as 1 to 2 percent overall air leakage. But through meta analysis in the HVAC industry, the spiral-seamed duct came into being. With some improved methods for connections, a rectangular system might have as little as 3 to 4 percent leakage. For many years, it was difficult to obtain less than 10 percent leakage in rectangular ductwork. ![]() ![]() The second efficiency advantage of spiral ductwork over rectangular is that air loss is much less with spiral. Smaller surface area means less resistance to air flow and less strain on the air handler. Screws are kept to a minimum due to fewer and better sealing joints. The seams are on the outside and there are no square corners or creases, providing a smoother surface for the air to travel. Why Spiral is Better: In a spiral duct, there is no internal seam to restrict air flow. When that happens, efficiency goes down, and the life expectancy of the components is also decreased. Yes, but it makes the air handler – or fan – that is pushing the air work harder. These all increase the static pressure inside your HVAC system. So here are at least four types of restriction that meets the air flowing through rectangular ducts: seams, creases, screws and greater surface area. Even if all else were equal – which it is not – the surface area of rectangular duct is more than in an oval or round spiral. In comparison, the perimeter of a spiral round duct of equal volume is only 41 inches, or about 15 percent less. A 12 X 12-inch rectangular duct has a perimeter of 48 inches. These factors all add resistance to the air flowing through rectangular ducts.ĭo the Math: A final way that resistance to air flow is found in the rectangular duct is by the fact that there is more surface area in a rectangle than a circle having the same area. ![]() Also, a rectangular duct usually has shallow diagonal creases in each of the sides to stiffen the duct and prevent it from flexing when the air turns on and off. When the duct is assembled, the seam is often secured by the use of screws. Rectangular ducts are often transported to the job site unassembled as flat stock because it is easier to load them in a truck and they take up less space. Depending on how it was made, it might even have two seams in opposite corners running along its length. Seams, Screws and Creases, Oh My: A rectangular duct has a seam that runs its entire length. Static pressure refers to the resistance that faces both the air flowing through the system and the components of the system itself. Here is one area where spiral ductwork is superior to rectangular because it minimizes static pressure. Just as blood flowing through our vascular system can be restricted by various kinds of blockages, so can the air in our HVAC system be restricted by features inside it. Whether we’re talking summer or winter, cooling or heating – we want air to flow through the ductwork smoothly and efficiently. In your HAC system, air flowing through the ductwork with as little hindrance is what it’s all about. There are several reasons spiral ducts are better. Here is our reasoning and the conclusion we’ve made in the rectangular ductwork vs spiral ductwork debate. We wouldn’t make a statement we can’t back up. Advantages of Spiral Ductwork over RectangularĪdvantages of Spiral Ductwork over Rectangular. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |