Repiping & Whole-Home Pipe Replacement
Replace aging galvanized, copper or early plastic supply lines with new PEX or copper across the house.
Homeowner guide
PEX vs Copper Pipe in Louisville, CO: Which to Choose
PEX is flexible plastic tubing. Copper is rigid metal pipe with a long track record. Both can serve a house for decades, and a good installer can do either well. The right pick depends on your walls, your budget and how cold your pipes get.
By the Flatirons Express Plumbing team ·
What each material is
Copper has been used in homes for generations. It is cut to length and joined with soldered or pressed fittings. It resists many contaminants and is easy to recognize. It can corrode if water chemistry is aggressive and can develop pinholes.
PEX, short for cross-linked polyethylene, comes in coils and is run with bends instead of many elbows. Fittings are crimped, clamped or expanded. It is lightweight, quiet and does not corrode.
Freeze tolerance
Water expands when it freezes, and rigid pipe can split. PEX can stretch somewhat and may survive a freeze that would burst copper, though it is not freeze-proof and fittings can still fail. Both need protection in unheated spaces.
In Front Range winters, pipes in garages and exterior walls are the weak points. Insulate them and keep cabinet doors open on cold nights, whichever material you have.
Installation and cost
PEX goes in faster with fewer fittings and less drywall damage, since it snakes through framing. That usually means lower labor cost. Copper takes more time, and soldering needs care around framing.
Material cost has varied over the years, and copper has often been the more expensive material. Ask for a written quote for each and compare labor and fittings, not only the pipe.
How the two materials compare
Both work well. This table shows where each one tends to shine.
| Consideration | PEX | Copper |
|---|---|---|
| Installation | Flexible and quick to run | Rigid, more fittings and labor |
| Freezing | Can expand somewhat, not freeze-proof | Splits more readily |
| Corrosion | Does not corrode | Can corrode in aggressive water |
| Sunlight | Degrades in direct UV | Unaffected |
| Cost | Often lower overall | Often higher overall |
Water quality and taste
Copper can leach small amounts of metal in aggressive water, and PEX can give a slight plastic taste when new that fades. Both meet drinking water standards when certified. Look for NSF/ANSI marking on the tubing.
If you have concerns about your water, test it and read your utility's report. Pipe material is only one of many factors.
Lifespan and warranty
Copper commonly lasts for many decades, and PEX manufacturers warrant their products for long periods when installed correctly. Neither is forever, and installation quality matters as much as the material.
Ask the contractor about workmanship warranty, the manufacturer's warranty and what voids it. PEX should not sit in direct sunlight, because UV can degrade it.
Fittings and connection methods
PEX systems use crimp rings, clamps or expansion fittings, each with its own tool. Copper uses solder, press fittings or compression connections. A skilled installer chooses the method that fits the job and the code.
Ask which fittings will go in. Brass fittings last well. Plastic fittings are used in some systems and carry their own pros and cons. A good installer explains the choice and shows you where joints will sit, especially if any will be hidden behind a wall.
Noise, pressure and flow
PEX is quiet and handles pressure surges a little better than rigid pipe, though it is no cure for water hammer. Copper can ring or tick as it heats and cools. Pipe sizing matters as much as material. A line that is too small for the load robs pressure at the tap.
If you are repiping an older house, have the installer plan sizes for the number of fixtures. A manifold system with a separate PEX line to each fixture can give steady pressure when two fixtures run together.
Permits and inspections
Replacing supply piping in a house usually involves a permit and an inspection in many places. The inspector looks at pipe support, joints and pressure tests. Your contractor should explain what is needed and handle the paperwork.
Ask to see the permit and the inspection sign-off when the job ends. Keep them with your house records. They matter when you sell the house, because a buyer's inspector may ask about the age and type of the plumbing.
Asking for a written scope
Whichever material you choose, ask for a written scope that lists pipe type, fittings, wall repair, permits and cleanup. A clear scope makes quotes comparable and prevents arguments over what was included.
Ask how the installer will protect your floors and furniture, how long the water will be off each day and what warranty applies to the work. A thoughtful installer answers these questions without hesitation.
Mixing materials in one house
Many houses end up with a blend. A repair on an older copper system may use a short run of PEX, and a remodel may add new PEX branches to a copper trunk line. With the right transition fittings, the two work together without trouble.
The detail to watch is the connection between different metals and plastics, and any contact between dissimilar metals that can cause corrosion. A qualified installer chooses fittings to suit and keeps the joints accessible where possible.
Which should you pick
If you are repiping a house with limited access, PEX often wins on speed and cost. If you prefer metal and the budget allows, copper is a solid choice. Some homes use both, with copper at the water heater and PEX in the walls.
For a whole-house project, see repiping. For a single leak, a burst pipe repair can use either, matched to the existing pipe.
Quick answers
PEX and copper questions
Certified PEX is approved for potable water. Look for NSF/ANSI marking.
Both can last for decades. Installation quality and water conditions matter.
Yes, with the right transition fittings. A plumber can do it.
PEX tolerates freezing better because it can expand, but it can still fail. Protect both.
Services that connect to this topic
Burst Pipe Repair
Stop the flow, then mend the cracked pipe, often one that froze during the night.
Leak Detection
Pinpoint a concealed leak in a wall, a ceiling or the buried supply line, so only the right spot gets opened.
Keep reading
Weak water pressure and what causes it
Weak flow at one tap and weak flow everywhere have different causes. Here is how to tell which you have.
What makes pipes bang when water stops
A bang when a valve closes is water hammer. It stresses pipes and fittings, and it is usually fixable with an arrestor or a pressure check.
How to thaw frozen pipes safely
If water stops at a tap on a cold day, a pipe may be frozen. Here is how to thaw it safely and when to shut the water off.
Planning a repipe or remodel?
Call and describe the house. A dispatcher can connect you with a local contractor.