Laying heating pipes: the right planning
Before laying the heating pipes, you should think about a detailed concept. In it, you answer key questions: Where should radiators be installed? Which material do you want to use? Both decisions represent a significant cost factor. Detailed planning is then done by a specialist.
The number and position of the radiators form the basis for the piping plan. The specialist calculates the appropriate dimensions for the radiators so that you can heat them at the lowest possible cost.
Which installation system should it be?
Heating pipes can be arranged and laid in a star or ring pattern. You’ll learn more about the differences in a moment.
Which system is the right one depends on the building: In multi-story single-family houses, the ring system is usually used. For bungalows or individual apartments, the star-shaped installation system is often suitable. Apartment buildings usually have a combination of both systems.
If several floors are to be laid with pipes, so-called risers are required. Specialists lay these vertically on the walls.
How do the laying systems differ?
In a star-shaped system, all heating pipes run from the manifold directly to the respective radiators. The manifold thus supplies the radiators directly with hot water.
In the ring-shaped system, all radiators are connected to a circumferential pipe system. This consists of two pipelines installed in parallel. The supply of hot water to the radiators is called the flow, and the reverse is the return. The latter conducts the cooled water back to the heating system, which heats it again.
Thus, in the ring system, there is a common return of all radiators, in the star or sun-shaped system each radiator has its supply and return. The pipes used must be of a corresponding size.
The right material for heating pipes
An advantage of heating pipes made of steel is that they can work with high temperatures and pressure. Their disadvantage is that they are susceptible to corrosion and are therefore not suitable for damp rooms. Moreover, you need to vent them regularly to prevent internal corrosion.
Heating pipes made of plastic are ideal for low-temperature systems up to 80 °C. They can be used for wall or floor heating. These include wall or floor heating systems. Plastic pipes do not rust and lose little heat during hot water transport. Their disadvantage is that they are more flammable and less resistant to mechanical stress.
Copper heating tubes are non-corrosive, easy to install, and ideal for small heating systems. Their disadvantage: they expand with temperature fluctuations, which is why they can only tolerate temperatures up to 100 °C. They also require effective insulation, as copper is an excellent conductor of heat. The raw material is now quite costly.
Length and diameter of heating pipes
The main pipes to and from the manifold usually have a diameter of 26 mm. Radiators up to 7 kW power, on the contrary, require pipes with a diameter of 20 mm. On the other hand, if the radiator does not produce more than 3.5 kW, 16 mm is also sufficient.
To find out how many meters of heating pipe you need, take a measuring tool and determine the distance of each radiator to the manifold or heater. Then double this distance. This value tells you how many meters of pipe is required for the flow and return.
Material for laying the heating pipes
To lay the heating pipes correctly, you will need several materials and tools. These include:
Soldering iron or welder
Brackets for the heating pipes
Material for sealing
Laying heating pipes – this is how it’s done
To ensure that the heat reaches the heating system and is not lost through the heating pipes, you must insulate the pipes effectively.
First, cut the pipes according to the installation plan. Grind the cut edges – this is called “deburring” – before you join them together using the fittings. Steel pipes also need a male thread.
All connections must be soldered, pressed, or screwed together with a suitable seal. Also, mark on each pipe whether it belongs to the supply or return. Connect the supply pipe to the top of the radiator and the return pipe to the bottom.
Insulate heating pipes
The further the heating pipes run through the house, the more heat is lost along the way. Heat loss can be reduced with effective insulation. For pipes that run through unheated rooms, this may even be required by law.
For insulation, there are so-called pipe shells made of PE foam or rubber. These are open all the way through on one side, so all you have to do is put them over the pipe and glue the slot shut. Make sure that the pipe clamps are also well-wrapped.
While insulation systems are usually easy to install, some of them are quite costly to purchase. Pipe shells made of rubber, for example, are flame retardant, but not as inexpensive as the PE alternative.
Surface-mounted heating pipes, for example in the cellar or attic, are best insulated with pipe shells made of rock wool with an aluminum surface: their thickness provides excellent insulation. Here, too, the final step is to glue the pipes properly so that the heat remains in the pipe.
Buy a little more insulation than you have calculated beforehand. This way you will be prepared for the waste that is sure to occur.
How much does it cost to install heating pipes?
For an average single-family home, you should budget around €15,000 to €18,000 for gas heating. The heating system takes up about 50% of that. The pipes account for between 25% and 30%, and the rest is for the house connection (natural gas).
When laying the heating pipes, the material costs usually account for around 50% of the total costs. So if you do the work yourself, you can save a good half. Installing the radiators also has its price. The material and labor costs are also about 50% each.
However, you cannot and should not completely do without a specialist. Because before you switch on the heating with the heating pipes you have laid, a plumbing specialist must carry out a pressure test. This is the only way to ensure that the heating system is working properly.
Plan the test run at a time when you have not yet plastered the wall slots of the internally laid pipes. In an emergency, heating pipes can still be replaced or leaks repaired.