Silver-Flex Duct
Are your ducts robbing you blind? Most modern Las Vegas duct systems, that is those installed within the last 5 years, are usually put together using R-6 silver-flex duct and sealed using duct mastic, or at the very least, the new generation of duct tape that resembles packing tape. Silver-flex duct is composed of a plastic inner liner wrapped in insulation which in turn is wrapped in an outer silver rip proof jacket. It is very versatile and lends itself well to attic installations. It does not have seams running the length of it such as in metal ducts, which becomes a source of air leakage, and is easy to seal well at its connecting joints well with some care and a little bit of effort. In the early 90’s the insulation was mandated at R-4.2, these days the minimum allowable insulation is R-6. Also, due to improvements in industry standards and greater care in installations from energy efficiency training and education, newer systems are generally installed to minimize air leakage and remain tight over time, even in very hot spaces such as Las Vegas attics.
Older systems, such as those installed going back into the mid-80’s. Are usually constructed of some type of plastic lined flex duct, or sometimes hard metal duct, but there was little thought given to minimizing air leakage and energy efficiency. Also these systems are more often than not put together with duct tape, which after several summers in a hot Las Vegas attic, loses is tackiness and after many years will become brittle and offer virtually no support or air sealing properties. The metal duct systems can most certainly be re-sealed using duct mastic at the joints, though to seal the seams that run the length of the ducts is very labor intensive as the insulation needs to be unwrapped and re-wrapped. In a tight space such as an attic this can be very tedious and time consuming work and is usually not recommended due to cost. Flex-ducts from this era can sometimes be re-sealed at the joints and sheet-metal air plenums (the metal boxes used to connect the ducts to the air conditioning and heating equipment).
Micro-Aire Duct
Micro-Aire Duct
Duct system materials used in the early 80’s and before do vary greatly depending on the home builder. Around Buffalo and Westcliff, and also around Lamb and Harmon, as well as other places around town, a lot of the homes use a duct system called Micro-Aire or micro-duct. This is a hard, rolled insulation made into a duct. There is no inner liner, the inside is made of a porous fiber board material that tends to trap dirt very easily. The joints on these ducts are notoriously leaky as they are butted up to each other to create a trunk/branch system sealed with duct tape. Because of the age of these systems the duct tape is very brittle and leaky. Also the these systems were installed using smaller than normal duct sizes as the idea was to use them in high static pressure applications using special equipment, but the equipment they used on these was not high static pressure, so they were essentially undersized duct systems which in itself will cause higher than needed energy bills.
Glass-Flex Duct
Another duct to watch out for is called Glass-Flex, this is a duct similar to modern day silver-flex except the inner liner is made of a net rather than plastic. We have seen variations of this duct where the liner is half plastic and half exposed fiberglass insulation, as if the plastic liner is there only to keep the duct rib wire properly spaced and not to carry the air. Whoever thought that lining an air duct with a net or exposed fiberglass was good idea should really have their head examined, even back in the day when air conditioning efficiency and performance was not a concern. If the duct that you see when you change out your air filter looks like a net or you see exposed insulation then you may have Glass-Flex duct.
This brings us to a specimen we pulled out of an attic earlier this year doing an install in the Paradise
Alumi-Best Duct
Palms area of Las Vegas near Flamingo and Eastern. It was stamped with what appears to “Alumi Best”, though there is no aluminum in the construction of it. It is essentially rolled cardboard wrapped in duct tape. There was no insulation around it and it was barely held together with brittle duct tape. The homeowner had power bills close averaging $600 a month in a 2800 square foot home during the summer months and could not cool his home below 86 in the afternoons. We were first called out to this home last winter and when we did the initial inspection, parts of the attic were warmer than the inside of the home due to the leaky duct system heating the attic.
Alumi-Best Duct
Ducts matter, no doubt about it. A leaky duct system can cost you big time, in money and comfort. If your ducts are of poor quality or installation they should definitely be addressed before equipment is replaced. Do not let a contractor talk you into new equipment if your duct system is old and leaky, especially if up-sizing the equipment is being considered. Thinking that equipment needs to be up-sized is definitely a red flag and if this is the case then you should have your ducts checked by a qualified contractor that cares. Also you should not have your ducts cleaned if they are older, at the very least you can make them leakier by agitating the old duct tape and joints and worse yet micro duct and glass flex can be hollowed so to speak with a spinning duct brush, releasing fiber glass particles into the air you breathe.
If your system can not keep up on hot days, if you have excessive amounts of dirt around your registers, or if you have excessively high power bills, these are all signs of a duct system that may need help. If you are unsure of the condition of your Las Vegas area duct system call Paradise Air to come out and check them, in most cases we can give you a no cost evaluation of your system and make recommendations that you can rely on.
