The short answer is $2000 to $4000 and up, depending upon the amount of prep, the number of coats, the amount of trim, and the paint used.Swimming Pool Plumbing: Rigid PVC vs. Flexible PVC, Which is Better? Visit any online pool and spa forum and you'll find that a leak is one of the most frustrating experiences a pool owner can have.  Finding, fixing, and not to mention paying for a leak will make anyone want to pull their hair out!  Needless to say, a pool builder needs to use the best installation methods and building materials available to prevent leaks along with all the bloody consequences that follow.  Today I want to turn our attention to the most fundamental component of a pool's plumbing:  Polyvinyl Chloride tubing....or PVC pipe.  There are two primary types of PVC pipe used in residential inground pool construction today:  Rigid PVC pipe and Flexible PVC pipe.  Let's compare these subterranean tubes to determine which you would rather have under your pool patio.

What Rigid PVC and Flexible PVC have in common: What makes Rigid PVC and Flexible PVC different: So far, we can basically see that we have a choice between a pipe that is stronger and more difficult to install verses one that is weaker and easier to install.  Vw Beetle Seat Covers LeatherAll things being equal, I'm going with the one that's easier to install!  Adhesive Vinyl Floor CoveringBut alas, things are never quite that simple, are they?  Rolling Laptop Bag Under Seat Flexible PVC pipe is much easier to install, but should never be used on an inground swimming pool....period! Why Flexible PVC pipe should never be used on an inground pool: 1.)  Several years ago while attending a seminar on inground pool plumbing the instructor passed a small section of pipe around the room. 

When it finally came around to me I was astonished!  It was a piece of 2" flexible PVC pipe with dozens of tiny holes in it.  My first thought was: 'What the heck?'  Then the instructor said one word....."Termites!"  Flexible PVC pipe is simply not suitable for underground use, but don't take my word for it: Kuriyama of America, a large distributor of flexible PVC states:Spa Hoses (flexible PVC pipe) can be damaged by rodents or insects, including termites. Spa Hose should not be used underground in areas infested by termites.  Our warranty does not cover damages caused by them...This product warning shall be given to every purchaser of Spa Hose. has this at the bottom of their flexible PVC page: "Note: Spa Hoses can be damaged by rodents or insects, including termites." Do I even need to ask if you have termites?  Does it really matter?  Why would you take the chance?  The more appropriate question is:  Why would a pool builder take the chance? 2.)  Flexible PVC pipe is much easier to puncture or crush than rigid PVC pipe. 

It's simply not as strong, and considering all the pressures exerted on underground pipe, strength is a good thing!  I have seen "flex pipe" crushed and punctured both during construction and while working in a yard with existing pipe in the ground.  Anyone digging in a back yard needs to use caution, but personally, I would feel much more comfortable digging in a backyard that I know has rigid pipe versus flex pipe. So Why is Flexible PVC used on Inground Pools? Although the swimming pool contractors that use flexible PVC on inground pools are in the minority, they are out there.  I believe and hope it's because they don't know any better.  There's no doubt that it saves time, and we all know that time is money.  The real question is: ‘Will you have it in your back yard?'  Needless to say I wouldn't and neither will any of my customers!  The last thing we need is to feed the termite population and waste our time finding and fixing leaks!  Please feel free to comment below and don't forget to subscribe to our blog before leaving. 

Walker - Flex Hose 1 year limited warranty Tubing Diameter (In): 4 Inch Inlet Diameter (In): 4 Inch Outlet Diameter (In): 4 Inch Exhaust Pipe Size (In): 4 Inch Exhaust Pipe Overall Length (In): 18 Inch Tubing Diameter (In): 5 Inch Inlet Diameter (In): 5 Inch Outlet Diameter (In): 5 Inch Exhaust Pipe Overall Length (In): 24 Inch 4 Inch I.D./O.D. 24 Inch 5 Inch I.D./O.D. 18 Inch Exhaust Pipe Size (In): 5 Inch Exhaust Pipe Overall Length (In): 36 Inch Go to Page 4I've written a lot about duct problems, especially those in flex duct because they're so abundant. A couple of years ago, I even wrote an article about whether or not flex duct should be banned. My answer was no but that we need better quality control. When I updated and reposted the article recently at Green Building Advisor, Jack Lagershausen, the executive director of the Air Diffusion Council, sent me a letter. Unlike a certain, very large company that threatened me a while back, the Air Diffusion Council was smart about it.

He admitted that the problems I wrote about are "far too common" and sent me a complimentary copy of their installation guide, Flexible Duct Performance & Installation Standards. Today, with the hope that some readers will act on this information, I'll give you a bit of an overview of this guide and encourage every HVAC company installing flex duct to invest the $15 and get a copy. Then use it to train your installers. The 25 page guide begins with a description of the classifications and characteristics of flex duct, then discusses how they're tested, listed, reported, and certified. Chapter 4 is where the meat of the manual is, the installation details, and that's the part I'll talk about here. Basically, what they tell you is not to do all those things I've shown here in this blog and how to install flex ducts properly. They also refer to standards from other organizations (ACCA, ASHRAE, ASTM...) because this is an installation guide, not a complete reference work. For duct sizing, they refer you to ACCA's Manual D, for example.

One interesting bit of info that many installers need to understand is that flex ducts need to have the inner liner pulled tight. If it's not tight, the friction rate jumps significantly, and that means the air flow takes a hit. The diagram below shows that if a flex duct has even 15% longitudinal compression, the friction rate doubles. With 30% longitudinal compression, the friction rate quadruples. Another problem that I see frequently is bends that are too sharp. The ADC standards say, "Keep bends greater than or equal to one (1) duct diameter bend radius." The language is a bit clunky, but the diagram below shows what they mean. If you can put an equal size duct inside the turn as shown below, they say you're OK. Another biggie that I see all the time is sagging ducts. The official recommendation from the ADC is that flex ducts should sag no more than 1/2" per foot of length between supports. The supports need to be at the manufacturer's recommended spacing, but no longer than 4' maximum.

The straps that hold up the flex duct need to be no less than 1.5" wide. The ADC standards give a lot of other details about installation, including one of the most important aspects, the connections. The skinny on that is to make sure you get a good, solid connection between the inner liner and the connector, seal it with mastic or tape, and then bring the insulation and outer jacket over the connection and seal it, too. One more little note about those connections: The first method they show is to connect the inner liner mechanically with a metal clamp, the kind shown at right. I've never seen one of these in the field, except on a couple of my own installations. They also show how to attach the inner liner with sheet metal screws. The fastener that's used most often, plastic zip ties, is only mentioned in the footnotes: "Nonmetallic clamps shall be listed and labeled in accordance with standard UL 181B and marked '181B-C'." The ADC standards provide good guidance for duct installers.

If someone follows them perfectly and the system is commissioned properly, it should work just fine. The problem, though, is quality control, and one way to help with that is to make it a little harder to do sloppy work. Mike MacFarland, a home performance contractor in California, wrote what may be the best advice ever given in a comment here in the Energy Vanguard Blog: The trick to getting these installations right is to use rigid ductwork for all "deviations from straight," then pull the ductwork taut between the two ends which now point towards each other. The big advantage over a full rigid installation is sound control- the installations are quieter than fully rigid ones. There you have it. Use flex duct for the straight runs and hardpipe everywhere else. If you really can't bring yourself to buy those sheet metal elbows, at least follow the Air Diffusion Council standards. The main reason we see so many bad installations is expense. It costs more use the right methods.

It costs more to train employees to do it right. It costs more to use materials that are harder to mess up. It costs more to do proper design and commissioning. The truth is that there are costs associated with doing it wrong, too. It's just that the homeowner usually bears those costs. My friend Robert Bean just posted an article about the cost of HVAC systems, which he prefers to call indoor climate systems. The chart below is from that article and gives you a feel for how much bang you're getting for your buck. Of course, Robert's Canadian, so you'll have to convert using the current exchange rate if you're here in the US. You really should go read his article because Mr. Bean is one of the most knowledgeable HVAC guys around. Check out the rest of his website, too. There's a wealth of information there. The bottom line in all this is that you get what you pay for. Should Flex Duct Be Banned by Green Building Programs? Don't Kill Your Air Flow with This Flex Duct Disease