Metal-plastic pipes and their application.
Increasingly, when carrying out repairs, heating batteries from polymeric materials replace outdated or broken cast iron or metal structures. 
Due to the fact that such products have a number of advantages:
- Simplicity. After all, to assemble such a system will not be very difficult; for this, no expensive equipment or specialist services are required;
- Durability. Since the material is resistant to corrosion, this greatly increases its working life;
- High throughput. Achieved due to the fact that the surface of the pipe inside is very smooth, which prevents deposition of sediment;
- Strength. Due to its composition, the plastic is very resistant to mechanical influences.
- Cost-effective. The cost of polymer materials is low, so the prices for such pipes are quite acceptable;
- Environmentally friendly. They do not emit harmful substances, and the absence of rust will ensure the purity of water;
- Lightness. Plastic pipes are light enough in weight, which greatly facilitates the process of their binding.
Metal-plastic is a multilayered material consisting of:
- Outer layer of polyethylene;
- layers of aluminum, a thickness of not less than 0.4 mm;
- inner layer of polyethylene;
- the adhesive layer alternates with all layers.
Due to aluminum foil, the product has strength and high flexibility, it helps to change the bend angle of the pipe in any direction. And the use of a high-quality adhesive layer will ensure tightness and strength.
When buying plastic pipes for a heating system, follow these criteria:
- , be sure to read the label in the product data sheet and provide information on the permissible temperature( for hot water and heating + 95 degrees, as well as a brief increase to +130);
- correctly chosen diameter of a pipe is already half of the matter. It should be such that water can move at a speed of 0.5 m / sec.
- choose only a certified product - this is a guarantee of quality;
Together, all these qualities ensure the uninterrupted operation of metal-plastic structures for 50 years.
Heating using polyethylene pipes.
Modern heating and hot water supply systems consist of various materials, one of which is polyethylene.
There are several types of polyethylene:
- LDPE;
- MDPE;
- HDPE,
where - PE or PEH is an abbreviation of the polyethylene grade, and LD, MD, HD is the density factor.
It is this indicator that affects the technical characteristics of the produced products, the higher the coefficient, the stronger the product will be. 
Advantages of polyethylene pipes are obvious:
- Simplicity in their connection( using adapters, using soldering or welding machines);
- Do not require large financial costs;
- Lifetime approximately 50 years;
- Low thermal conductivity( allows to preserve heat and prevents condensation);
- Sufficient flexibility;
- No special conditions of storage and transportation;
- Resistant to aggressive environments.
The main characteristics of polypropylene and polyvinyl chloride.
Another type of plastic construction - polypropylene and PVC products. According to technical characteristics, they have the same range of advantages as other types of plastic. But, perhaps, the most important secret of their popularity is the cheapness and variety of accessories to them. 
But there are some drawbacks that are undesirable for the hot water supply and heating system, namely the inability to use at temperatures above +70 degrees.