DIY PEX Plumbing and Radiant Heating

There are several reasons why PEX is quickly replacing copper in many plumbing applications throughout the United States. These include lower cost of material, the level of difficulty of making connections which also leads to lower labor costs, the likelihood of pipes bursting, product availability and color coating. Check out these great articles to learn more on the topic of your choice.

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Learn About PEX Plumbing Systems
Sift Through the Best Selling Pex Supplies
Radiant Heat 101 Learning Center
Read About Radiant Heat System Set-up
Decide Which Tankless Waterheater is For You
Read More on Pex Plumbing
Radiant Heat and PEX Tubing Glossary
Learn About the Best Radiant Heat Systems
Baseboard Heating Calculator
Radiant Heat Quotes
Do-It-Yourselfers

Do you want to learn How to Build a House? Maybe you are interested in learning about PEX Plumbing? How about understanding the Cost to Build a House? For these questions and many more visit Home Building Questions today.

AquaPEX, HydroPEX, Viega, Watts, Zurn, the list goes on and on. There are now more than 20 different brands of PEX tubing for plumbing systems on the market! It can be difficult to decide which brand to go with and to have a good reason for the choice.

Let's simplify the decision making process: AquaPEX, made by Wirsbo (Uponor) is the highest quality tubing available on the market today. AquaPEX is PEX-a tubing and therefore is more homogeneous (with the chemical bonds evenly spread out) making it both stronger and more flexible. These characteristics come from the Engel production method for PEX-a tubing.

Because of the tubing's strength it is able to hold up better to freezing conditions, and it can be unkinked using a heat gun. It is also the only brand of PEX plumbing tubing that can be used with the Wirsbo Expander System. All other brands of PEX tubing can be looked at as a group. When purchasing another brand of tubing, be sure the product is being made by a reputable manufacturer, has at least a 20 year warranty, meets ASTM standards, and meets the desired pressure ratings.

If you follow these guidelines you will come up with a group of products that includes HydroPEX, Viega PEX, Watts PEX, and Zurn PEX. When comparing these products, price or brand preference will often be the deciding factor.

PEX stands for Poly Ethylene Cross (X)-Linked. It is the cross-linking process that makes PEX strong, safe and reliable, and it is how this process is done that determines what grade, or category, the PEX belongs to.

Depending on the grade of PEX that you choose, the flexibility, strength, and uniform nature of the material will be affected. The letters tell you how the PEX was created and the quality of the PEX, with A being the highest grade, followed by B, and finally C.

PEX-a
PEX-a is made using the Engel (or peroxide) method to crosslink the molecules of polyethylene. With this method, the crosslinking is done at a high temperature above the melting point of the crystals. This "hot crosslinking" produces an incredibly uniform material with no weak spots.

The Engel method produces the strongest, most flexible PEX tubing possible, allowing for an installation with fewer joints and fittings than any
other type of PEX. PEX-a also features a strong thermal memory and freeze protection, which means that once the tubing is expanded or contracted, it will naturally go back to its original shape.

Since the process takes more time and more sophisticated equipment, PEX-a tends to be a bit more expensive than PEX-b or PEX-c. AquaPEX is the only PEX-a material available for plumbing applications. Examples of PEX-a for radiant heat include ThermaPEX and hePEX.

PEX-b
PEX-b is made using the Silane (or moisture cure) method. This method performs the crosslinking with a chemical agent where the process is accelerated using heat and moisture. This chemical crosslinking is susceptible to some areas where the bonds are weaker than others and a slightly stiffer final product than PEX-a. Examples of PEX-b include HydroPEX, Watts PEX, and Viega PEX.

PEX-c
PEX-c is made using the Electron beam (or radiation) method. This method takes the polyethylene and passes it under an electron beam multiple times in order to get to the desired level of crosslinking. This is the most energy-efficient method of creating PEX, but often results in a more brittle, less consistent product than PEX-a or PEX-b. Electron beam is also the least expensive method and therefore creates the least expensive tubing.

When deciding which grade of PEX is right for your application, you should think about the layout of your tubing. If many tight bends need to be made, it is likely worth the extra few dollars for PEX-a so that you can avoid breaks in the tubing to insert elbows. PEX-a is also probably worth the extra money if the tubing will be exposed to very cold temperatures or to make the installation process easier.

Pex Plumbing system design can be done in a similar fashion to traditional Plumbing Systems. However, because of its flexibility PEX saves time and money as compared to installing traditional copper plumbing systems.

The options for running PEX in a plumbing system are listed below, they are not listed in any preference order.

Home-run Installation

In this system central manifolds are used to distribute water to all of the fixtures in a given residence or building. Manifolds may either be valved or valveless and are generally made of copper or engineered plastic.

If they are valveless, shutoff valves must be used at each fixture. These manifolds contain between 3 and 12 ports (generally 1/2") to connect PEX Tubing to. One of the central manifolds will receive cold water, and one manifold will receive the hot water supply. Each fixture will then have one dedicated cold PEX Tubing line and one dedicated hot PEX Tubing line which begin at the manifolds. Using this method minimizes the overall number of connections required.

This method also takes advantage of the flexibility of PEX Tubing. One main benefit of this setup is the reduced time required for hot water to reach the fixture.

Remote Manifold Installation

In this PEX Plumbing installation method close-end remote manifolds are placed near groups of fixtures, i.e. a bathroom. Two manifolds, one hot and one cold are placed close to the group of fixtures. PEX Tubing is then run from the manifold to each fixture. Valveless manifolds are typically used, however valved manifolds may be used as well.

Structured Plumbing Installation

Structured PEX Plumbing systems make use of the recirculation of hot water. Manifolds in this system will be located near groups of fixtures. For the hot water lines, open ended manifolds are used. By doing this, the hot water return line is created as an extension of the hot water supply line. This system's main benefit is a reduction in the usage of water and energy due to the on demand recirculation.

Modified Home-run Installation

This method is similar to home run installation, but it uses several flow-through manifolds instead of central manifolds. These open ended manifolds may be either valved or valveless. This method uses less PEX tubing than the home run method and may provide hot water faster than other installation methods.

Run-and-Branch Installation

This method is also referred to as "teeing off". It is commonly used in rigid plumbing systems such as copper and CPVC. A PEX fitting such as a tee or elbow is used each time the tubing needs to be split or change direction. This method requires more connections than other methods of PEX Plumbing. This method does not take full advantage of the flexibility of PEX Tubing.

For all of these installations the system should be inspected and pressure tested prior to being filled with water. The system should be pressure tested to between 40 and 60 psi.

With so many PEX tools and fittings available it can often be difficult to select the right tool for your job. The information and compatibility table on this page will help you make the right choice for your job.

PEX Plumbing - Selecting the Right Tool, Fittings, & Pipe for Your Job

If you are a DIY and have a one-time PEX job with a small number of connections you can utilize the SharkBite connection system. SharkBite fittings are easy to use and although they are expensive per fitting, they don't require a PEX tool.

Therefore the simplest and most inexpensive way for a DIY to complete a small PEX job is with SharkBite PEX fittings. As you can see from the table, SharkBite fittings are compatible with all standard ASTM size PEX pipe, they can also be used with copper pipe.

They can't be used with PEX-AL-PEX pipe.

For DIY's or professionals with a large one time job, or if you plan on having PEX jobs in the future, you will have several different options. These options include the Wirsbo Expander System, the PEX Crimp system or the PEX Clamp system, and the Viega Press System. We will discuss each of these in more detail and make some basic recommendations.

The PEX Crimp System and PEX Clamp System are the most simple and most often used by DIY's, however they are also popular with professionals in certain areas of the country. Both of these systems make use of the same barbed crimp fittings.

The difference between the two fittings is that the PEX Crimp System uses a Crimp tool and copper crimp rings, while the PEX Clamp System uses a Clamp Tool and stainless steel clamps. In terms of a recommendation here, the clamp system is slightly easier to use and cheaper. These systems can be used with any standard ASTM size PEX pipe, but can't be used with PEX-AL-PEX.

The Uponor Wirsbo Expander system is perhaps the most widely used PEX system by professionals in the US. This system makes use of the ProPEX Expander Tool ProPEX Fittings, ProPEX Rings, and PEX-a tubing. If PEX-a tubing (AquaPEX) is not used the connections will fail. This system makes strong reliable connections that have never failed in the field.

The only downsides to this system are the high up-front cost of the tool, the high price of fittings, and the fact that Wirsbo only wants professionals using the tools. Wirsbo has addressed the price of fittings by coming out with engineered plastic fittings that are more cost effective. Using the tool can be a little tricky at first, and Wirsbo prefers that only professional installers use their products. The Viega PEX Press System is growing in popularity with professionals across the country.

It has recently become available to DIY's through the Internet. This system utilizes a Viega PEX press tool PEX press fittings, and Press Sleeves. Some people have tried to use the PEX Press tool with crimp fittings, and for the most part it has worked, but this is not recommended by the manufacturer, and they will not honor the warranty if a leak occurs. Contractors in our local area enjoy working with this tool due to its ease of use and the strong connections it makes.

The Press technology is unique to Viega and has been used for many years. Similar to the Expansion system, the only down sides to this system are the high up-front cost of the tool, the high price of fittings, and the fact that Viega only wants professionals using the tools. This system can be used with any standard ASTM size PEX pipe, and Viega FostaPEX Tubing.

ProPEX Fitting Connection

Cut the end of the tubing perpendicular to the length of the tube. All of the material or burrs that are created from the cut should be removed. Slide the ProPEX ring over the end of the PEX Tubing. The ring should be extended over the tube by 1/16". Separate the two handles of the tool, and slide the expander head into the PEX until it stops.

Bring the handles together to expand the tubing. Remove the head from the tube and rotate a 1/8". Slide the tool head into the tubing in the newly rotated position and expand again. Repeat the expansion process until the tubing and ring are snug against the shoulder of the expander head. For 1/2" make 2-3 expansions, 5/8" make 5-7 expansions, 3/4" make 7-9 expansions, and 1" make 12-14 expansions.

When tubing is expanded, remove the tool, and insert the fitting. There will be some resistance as the tubing slides over the fitting. The tubing and ProPEX ring must be seated against the shoulder of the fitting to secure a proper connection.

Note: ProPEX connections can't be made for PEX-AL-PEX Tubing.

PEX Fitting Connections (For use with Clamp Tool)

Clamping connections may be made on any brand of PEX Tubing. However, it may not be used on PEX-AL-PEX Tubing. Clamps come in 3/8", 1/2", 5/8", 3/4", and 1". These clamps all work with the same clamping tool and may be used with the different sizes of PEX Tubing.
Cut the PEX Tubing so a straight end is created.

Slide the clamp over the end of the tube. Insert a SSC fitting into the tube so that the tube is fully covering the inserted barb. The clamp should then be moved between 1/8" - 1/4" from the end of the tube. Place the opened jaws of the ratchet tool over the ear of the clamp. Compress the tool until you feel a click, then lock it in a perpendicular position.

Compress the tool handles together to complete the connections. The tool will release when assembly is complete.

Note: Crimp/Clamp connections cannot be made for PEX-AL-PEX Tubing.

Compression Fitting Connections

Compression fittings may be used to make connections for PEX and PEX-AL-PEX tubing. Compression fittings do not require a special tool.

SharkBite PEX Fittings

SharkBite Push-Fit Fittings are designed to simplify pipe installation. The fittings allow users to connect pipe in seconds with ease. Instant push-fit connection for increased ease of use. Certified to 200 psi and 200°F (93°C). Fits OD controlled copper, CPVC, or PEX pipe. Body composed of solid DZR brass.

Do you want warm floors? Radiant floor heat is easier and less expensive to install than you think. There are several installation methods depending on your needs and radiant heat can be used either as a primary or secondary heating source. Both electric and hydronic radiant heats are available so there's sure to be an option that works with your home.

Radiant Heat Installation

Why would you want radiant heat in your home and what are the benefits?
Comfort is the biggest benefit. With radiant heat, heat is distributed evenly through the floors, warming them and then rising up throughout the rest of the room. When the floors are warm, the objects in the room (couches, chairs, and so on) become warm, and you become warm and comfortable. Radiant heat allows you to keep the average temperature a few degrees lower than you're used to but feel just as warm or even warmer. This saves energy and directly saves you money. Radiant heat is also silent with no creaking, rattling, banging, popping, humming or whistling. And there are no visible components with radiant heat so it will always fit in perfectly with your style.

Why is radiant heat better than conventional heating systems?

Comfort, even heating eliminates the pockets of hot and cold typical of traditional radiator or convection heating systems. Instead of being warm right next to the heater and freezing on the other side of the room, radiant heat keeps the same temperature throughout the room by allowing heat to naturally rise.

Installation

The 4 basic methods of installation are In-slab, joist, overpour, and wood panel tracks. When you decide to install radiant heat, you'll need to decide how you'll be doing the installation. This decision is largely based on the space available and the layout of your home.

In-Slab Installation

If the concrete slab has not yet been poured for new construction or a large remodel, an in-slab installation is the best way to go. With this method, you will lay out your loops of tubing, and then pour the slab. When hot water circulates through your PEX, the entire slab will heat up and radiate its heat into the room. The slab becomes a large thermal mass and will stay warm for a long time, meaning that your room will stay warm for a long time with little energy usage. This is also the most cost effective method. When installing in a slab, it is especially important to pressure test. If there is a leak, you want to know before you pour the concrete!

Joist Installation

If your floors are down but you have access to the joist spaces beneath them, joist installation is for you. When doing a joist installation, you will need aluminum joist trak panels to secure in the joist spaces and push the tubing into these panels. The aluminum panels will heat up and hold their heat to warm your room. With joist installation, you can also use suspended pipe installation where you do not utilize the aluminum panels. While this is less expensive to install, you will need to run hotter water through your tubing and it will not heat your room or hold the heat as well as with the aluminum panels. If you already have a slab, and do not have access to the joists, there are 2 more options for you.

OverPour Installation

If you can raise your floors 2-3 inches, you can do an overpour of a lightweight concrete (mud or gypcrete) onto your existing slab. With this installation method, you will lay the PEX tubing onto your existing slab and then pour another 2 to 3 inches of concrete on top. The top layer must be poured so that there is a minimum of 3/4" of an inch above the highest point of your tubing. The new layer of concrete will be warmed in the same way as the in-slab installation, and this layer will retain its heat and pass it to your room.

Wood Panel Track Installation

If you cannot raise your floors by 2 inches, you can utilize wood panel track radiant heating that will only raise the floors about a half inch. For this method, you can purchase wood panels and press PEX tubing into the grooves cut out of the wood. Some panels (such as the Quik Trak panels) have an aluminum heat transfer sheet built in and can easily be combined to fit the size and shape of any room. Both straight tracks and return tracks must be used to create your loops.

PEX Tubing: Crosslinked PolyEthylene (or PEX)- make sure that it has an oxygen barrier for closed systems- flexible enough to bend easily and strong enough to be approved by all major plumbing and heating codes. 1/2" is the most common size for radiant heat.

Manifold: The hub of your radiant heating system connecting to the supply and return lines through supply and return balancing manifolds, with as many ports as you have loops of tubing. If you have more than 12 loops in your system, multiple manifolds may be necessary. For half inch tubing, no loop should be longer than 300 feet.
Circulator Pump: Usually Taco or Grundfos, to circulate the water throughout the system. If there won't be potable water involved, a cast iron pump is a cost efficient way to get the job done.

Check Valve: To assure that water can only flow one way through the system.

Water Tempering Control: Including mixing valves, I-series valves, mixing blocks and Tekmar controls. Boiler water cannot go directly into the hydronic radiant system; the water must be mixed with cold water, ultimately sending a maximum of 150°F water through your PEX to heat your floors.

Thermostat: The interface between you and your heating system, the thermostat will control when the heat is turned on and how long it stays on to achieve the desired temperature in the room.

Sensors: In-slab sensors will communicate to the thermostat the temperature of the slab while floor sensors will communicate the surface temperature of your floors to prevent any gapping, cupping or warping due to excessive heat.

Expansion Tank: To maintain proper pressure within the system.

Air Eliminator: Removes all excess air from the system to ensure silence and a steady water flow during operation.

Zone Valves: If you want to keep different rooms at different temperatures, you will need to create separate zones.

Pressure Test Kit: Make sure to test the pressure in your system to ensure that there are no leaks. Testing should be done at maximum system pressure before, during, and after an installation to be sure the system is running properly before you put it to work.

A Loop CAD Design: If it's your first time dabbling in radiant heat or you just want to be sure it's done right, you can get a loop CAD drawn by a Radiant Certified Designer. A custom loop CAD with a materials quote for your home is $150 from my affiliates at PexSupply.

PEX Tubing: Barrier vs Non-Barrier vs PEX-AL-PEX

Once you have decided to use PEX, you have another decision to make: what kind? Barrier, no barrier, aluminum, let's get them straight. Making the decision of whether to use Barrier PEX, Non-Barrier PEX, or PEX-AL-PEX is largely based on what job you are going to use it for and what other components you will be working with. All three types of tubing are PEX (Poly Ethylene X-Linked) but some have extra features built in.

Barrier PEX

The "barrier" referred to in PEX tubing is actually an oxygen barrier. This extra layer in your tubing will assure that no oxygen gets into your heating system. Oxygen in your system can be a problem that causes your system components to rust. The oxygen barrier and rust prevention allows you to use cast iron components in your system instead of all brass or bronze, which makes components like pumps and flanges substantially less expensive and keeps them running smoothly for longer. Antifreeze
can also break down a system with no oxygen barrier.

For radiant heat applications using closed systems, barrier tubing is by far the most popular choice.
Examples of barrier tubing include Wirsbo hePEX, Thermapex Tubing, and HydroPEX Barrier Tubing. This style of tubing will save you money when buying parts and will prevent rust and corrosion.

Non-Barrier PEX

Non-barrier tubing is simply PEX tubing without the oxygen barrier. For potable water applications, you will generally use non-barrier PEX. Oxygen barrier PEX is made for heating applications and has thus not been approved for plumbing and drinking water. When using tubing without an oxygen barrier, you must be careful to assure that each and every component in your system is non-ferrous (meaning that it contains no iron).

Non-barrier PEX Tubing is rarely seen in radiant heat systems, the few systems that do utilize non-barrier PEX are open systems.
Non-barrier PEX for plumbing is available in red, white, and blue. Typically, red is used for hot water and blue is used for cold so that you can immediately see which line goes where when looking at a manifold. White can be used instead of either or both colors as all three colors are made of identical material. Non Barrier PEX Tubing includes Wirsbo AquaPEX, ViegaPEX, and HydroPEX Tubing.

PEX-AL-PEX

PEX-AL-PEX is a three-layer PEX Tubing that also has an oxygen barrier. PEX-ALPEX is a layer of PEX, a layer of aluminum, and another layer of PEX. The main benefit of PEX-AL-PEX is that it holds its shape. Where traditional PEX is flexible, there is nothing that keeps it in place unless you tie it down every few feet. With PEX-AL-PEX, once you bend it, it will hold that shape until you bend it again. PEX-AL-PEX also has less expansion than standard PEX with the layer of aluminum assuring that it keeps its
shape.

PEX-AL-PEX is frequently used in outdoor heating applications,
warmboard systems and for high temperature systems like baseboard and fan
coils.
Mr. PEX-AL-PEX, Wirsbo Multicor, and FostaPEX are all examples of PEX-ALPEX Tubing.