I work as a plumber, in the article, I will briefly and clearly inform the readers where to apply a certain type of polymer pipe, its price, the cost of the tool and the complexity of installation. According to these criteria, everyone will determine for himself which pipe is "related" or "looks" at you.
In estimating the cost of the pipe and tool, I will take the price tag from a large green store. And the complexity of installation and the price for this work will be subjective.
Polypropylene
They withstand mechanical stress well, it is difficult to damage the integrity of the pipe. Withstands relatively high temperatures. For heating installation use glass fiber reinforced polypropylene, this layer reduces the linear expansion of the pipe and improves the strength characteristics. Aluminum reinforced polypropylene also reduces the linear expansion, but besides this, it well protects the system from the penetration of oxygen into the coolant. This pipe is lightweight, low cost, does not corrode and does not overgrow with a thick layer of sludge. Of the minuses, it does not tolerate too high a coolant temperature. It is not used for installation in a warm floor, because it is supplied in whips and is not flexible enough. It is very popular on the market, so there are dishonest manufacturers who reduce the cost of production of pipes and fittings by saving on material.
On average, the cost of a pipe with a diameter of 20 mm, per meter is from 50 to 80 rubles.
A welding machine and scissors can cost from 1,500 rubles, which is not quite expensive.
The complexity of the installation of pipes and fittings is high, as it requires a certain skill and understanding of soldering processes in difficult conditions.
XLPE
It is mainly used for the installation of underfloor heating, but radiators are often connected by them, especially with hidden laying. The pipes are connected with compression fittings. Many believe that the characteristics of "cross-link" are better than polypropylene, especially after the installation of the system, since the diameter of the pipes does not narrow and there is no human factor affecting the characteristics of the joints. Of the minuses, I can note that the pipe has a memory and when installing pipes in a warm floor, you need to fix them well. An EVOH layer is used to protect the pipes from oxygen penetration.
As you can see, the price for one meter of pipe will be from 63 rubles and more, but you should not trust the low price. Do not forget the saying that "a fool pays three times."
The cost of an apparatus for installing fittings is very high, so it is more prudent to rent this tool if you work one-time at your facility.
The complexity of installation is low, even if the fitting is crimped incorrectly, the connection can be heated with a hairdryer and disconnected. And then reapply the pipeline parts.
Metal-plastic
At one time, it was used everywhere, until the advent of the low-quality "Chinese" pipe, which served a short time and tarnished the reputation of the entire maytapol market. This pipe consists of five layers. Two layers of PEX or PERT plastic, one layer of aluminum, and two layers of adhesive. Due to aluminum, the pipe does not allow oxygen to enter the system and maintains its predetermined shape. It is well mounted both hidden and outdoor. Collet mounting of fittings and connections does not require special tools. Does not corrode. Has no critical linear expansion.
The disadvantages include the failure of the pipeline during defrosting and cracking at the wrong temperature conditions. The flow area is narrowed in the fittings.
As you can see, the pipe does not have a high price, but it should be taken in proven places and only branded.
When installing with collets, although I do not welcome this type of connection, only adjustable wrenches are required.
The complexity of installation is not high for her, with certain skills.
In general, from the above characteristics and features of each material, one can draw conclusions and come to a compromise. Because there are no ideal polymer pipes.
From SW. Your author in Ya. Zen Mikhailov Victor