We understand together: what is more efficient single-pipe or two-pipe heating system?


Own­ers of pri­vate hous­es often face the choice of which type of home heat­ing to give pref­er­ence. There are only two types of heat­ing sys­tems tra­di­tion­al­ly used in every­day life: one-pipe and two-pipe. Each type has both advan­tages and dis­ad­van­tages. The dif­fer­ence between both sys­tems lies in the dif­fer­ent way of deliv­er­ing the coolant to the heat­ing devices. Which heat­ing struc­ture for your own home is bet­ter, one-pipe or two-pipe — choose direct­ly to the own­er of the house, tak­ing into account their own domes­tic needs, the esti­mat­ed heat­ed area and the avail­abil­i­ty of finances.

In the first ver­sion, heat is dis­trib­uted through­out the house through one pipe, sequen­tial­ly heat­ing each room of the house. In the sec­ond case, the com­plex is equipped with two pipes. One is a direct sup­ply of coolant to the radi­a­tors. Anoth­er pipe serves to drain the cooled liq­uid back to the boil­er for sub­se­quent heat­ing. A cor­rect assess­ment of one’s own finan­cial capa­bil­i­ties, an accu­rate cal­cu­la­tion of the opti­mal para­me­ters of the coolant in each indi­vid­ual case, will help not only deter­mine the type of heat­ing sys­tem, but also cor­rect­ly install the heat­ing.

You can under­stand and fig­ure out what is best for you, a one-pipe or two-pipe heat­ing sys­tem, only after a thor­ough study of the tech­ni­cal nuances.

Single pipe heating system. General representations

A sin­gle-pipe heat­ing sys­tem can work both with a pump and with nat­ur­al cir­cu­la­tion of the coolant. Con­sid­er­ing the sec­ond type, you should delve a lit­tle into the exist­ing laws of physics. It is based on the prin­ci­ple of expan­sion of a liq­uid when heat­ed. Dur­ing oper­a­tion, the heat­ing boil­er heats the coolant, which, due to the tem­per­a­ture dif­fer­ence and the pres­sure cre­at­ed, ris­es through the ris­er to the high­est point of the sys­tem. The move­ment of the coolant upwards is car­ried out along one pipe, reach­ing the expan­sion tank. Accu­mu­lat­ing there, hot water fills all series-con­nect­ed bat­ter­ies through a descend­ing pipe.

Accord­ing­ly, the first con­nec­tion points along the course of the coolant will receive max­i­mum heat, while par­tial­ly cooled liq­uid will already enter the radi­a­tors locat­ed fur­ther.

For large, mul­ti-storey build­ings, such a scheme is extreme­ly inef­fi­cient, although in terms of instal­la­tion and main­te­nance costs, a sin­gle-pipe sys­tem looks attrac­tive. For pri­vate one-sto­ry hous­es, res­i­den­tial build­ings with two floors, a sim­i­lar prin­ci­ple of heat dis­tri­b­u­tion is accept­able. Heat­ing res­i­den­tial premis­es using a sin­gle-pipe scheme in a one-sto­ry house is quite effec­tive. With a small heat­ed area, the tem­per­a­ture in the radi­a­tors is almost the same. The use of the pump in longer sys­tems also has a pos­i­tive effect on the uni­for­mi­ty of heat dis­tri­b­u­tion.

The qual­i­ty of heat­ing and the cost of instal­la­tion in this case may depend on the type of con­nec­tion. Diag­o­nal con­nec­tion of radi­a­tors gives greater heat trans­fer, but is used less often, due to the larg­er num­ber of pipes need­ed to con­nect all heat­ing appli­ances in res­i­den­tial premis­es.

The scheme with the low­er con­nec­tion of radi­a­tors looks more eco­nom­i­cal due to the low­er con­sump­tion of mate­ri­als. From an aes­thet­ic point of view, this type of con­nec­tion looks prefer­able.

Advantages of a single-pipe heating system and its disadvantages

For own­ers of small res­i­den­tial build­ings, a sin­gle-pipe heat­ing sys­tem looks tempt­ing, espe­cial­ly if you pay atten­tion to its fol­low­ing advan­tages:

  • has sta­ble hydro­dy­nam­ics;
  • con­ve­nience and ease of design and instal­la­tion;
  • low costs for equip­ment and mate­ri­als.

The indi­rect advan­tages of a sin­gle-pipe sys­tem include the safe­ty of the sup­ply of coolant, which diverges through the pipeline through nat­ur­al cir­cu­la­tion.

The most com­mon prob­lems that own­ers of a sin­gle-pipe heat­ing sys­tem have to face include the fol­low­ing aspects:

  • tech­ni­cal dif­fi­cul­ties in elim­i­nat­ing mis­cal­cu­la­tions in the work made dur­ing the design;
  • close rela­tion­ship of all ele­ments;
  • high hydro­dy­nam­ic resis­tance of the sys­tem;
  • tech­no­log­i­cal lim­i­ta­tions asso­ci­at­ed with the impos­si­bil­i­ty of inde­pen­dent adjust­ment of the coolant flow.

Despite the list­ed dis­ad­van­tages of this type of heat­ing, a well-designed heat­ing sys­tem will avoid many dif­fi­cul­ties even at the instal­la­tion stage. In view of the list­ed advan­tages and the eco­nom­ic com­po­nent, sin­gle-pipe schemes have become quite wide­spread. Both a sin­gle-pipe and anoth­er type, a two-pipe heat­ing sys­tem, have real advan­tages. What can you win and what can you lose by choos­ing one of the types for your home?

Technology for connecting and locating a single-pipe heating system

Sin­gle-pipe sys­tems are divid­ed into ver­ti­cal and hor­i­zon­tal. In most cas­es, ver­ti­cal wiring is used for mul­ti-storey build­ings. In this case, all radi­a­tors are con­nect­ed in series from top to bot­tom. With hor­i­zon­tal wiring, the bat­ter­ies are con­nect­ed one after the oth­er hor­i­zon­tal­ly. The main dis­ad­van­tage of both options is fre­quent air jams, due to the accu­mu­la­tion of air in the radi­a­tors. The pro­posed scheme makes it pos­si­ble to get an idea of ​​​​some wiring options.


Con­nec­tion meth­ods in this case are select­ed at the dis­cre­tion of the own­er. Heat­ing radi­a­tors can be con­nect­ed via side con­nec­tion, diag­o­nal or bot­tom con­nec­tion. The fig­ure shows sim­i­lar con­nec­tion options.

For the own­er of the house, the eco­nom­ic fea­si­bil­i­ty of the equip­ment installed in the house and the effect obtained are always an impor­tant aspect. Do not under­es­ti­mate the option with a sin­gle-pipe heat­ing sys­tem. Today, in prac­tice, quite effec­tive mea­sures are being tak­en to improve heat­ing schemes of this type.

For exam­ple: there is a tech­ni­cal solu­tion that allows you to inde­pen­dent­ly adjust the heat­ing of indi­vid­ual radi­a­tors con­nect­ed to the same line. For this pur­pose, bypass­es are cre­at­ed in the sys­tem — a pipe seg­ment that cre­ates a bypass move­ment of the coolant from a straight pipe to the return, bypass­ing the cir­cuit of a cer­tain bat­tery.

Valves and valves are placed on the bypass­es, block­ing the flow of the coolant. You can install ther­mostats on radi­a­tors that allow you to con­trol the heat­ing tem­per­a­ture in each radi­a­tor or through­out the sys­tem as a whole. A com­pe­tent spe­cial­ist will be able to cal­cu­late and install bypass­es to achieve max­i­mum effi­cien­cy. In the dia­gram you can see the prin­ci­ple of oper­a­tion of bypass­es.

Two-pipe heating system. Operating principle


Hav­ing become acquaint­ed with the first type of heat­ing sys­tem, a sin­gle-pipe, it’s time to deal with the fea­tures and prin­ci­ple of oper­a­tion of a two-pipe heat­ing scheme. A thor­ough analy­sis of the tech­no­log­i­cal and tech­ni­cal para­me­ters of heat­ing of this type allows con­sumers to make an inde­pen­dent choice — which heat­ing is more effi­cient in a par­tic­u­lar case, one-pipe or two-pipe.

The basic prin­ci­ple is the pres­ence of two cir­cuits along which the coolant diverges through the sys­tem. One pipe pro­vides the coolant sup­ply to the heat­ing radi­a­tors. The sec­ond branch is designed so that the already cooled coolant, after pass­ing through the radi­a­tor, returns back to the boil­er. And so con­stant­ly, in a cir­cle, while the heat­ing is on. At first glance, the very pres­ence of two pipelines in the scheme can repel con­sumers. The long length of high­ways, the com­plex­i­ty of wiring are fac­tors that often scare own­ers of pri­vate hous­es away from a two-pipe heat­ing sys­tem.

This is at first glance. Like sin­gle-pipe sys­tems, two-pipe sys­tems are divid­ed into closed and open. The dif­fer­ence in this case lies in the design of the expan­sion tank.

Closed two-pipe heat­ing sys­tems of a pri­vate house with a mem­brane expan­sion tank are the most prac­ti­cal, con­ve­nient and safe to use. The obvi­ous ben­e­fits are con­firmed by:

  • even at the design stage, it is pos­si­ble to equip heat­ing devices with ther­mostats;
  • par­al­lel, inde­pen­dent con­nec­tion of radi­a­tors;
  • the tech­ni­cal pos­si­bil­i­ty of adding heat­ing devices after the instal­la­tion is com­plet­ed;
  • ease of use of hid­den gas­kets;
  • the abil­i­ty to turn off indi­vid­ual radi­a­tors or branch­es;
  • ease of adjust­ment of the sys­tem.

Based on the fore­go­ing, one unam­bigu­ous con­clu­sion can be drawn. A two-pipe heat­ing sys­tem is much more flex­i­ble and more tech­no­log­i­cal­ly advanced than a sin­gle-pipe one.

For com­par­i­son, the fol­low­ing dia­gram is pre­sent­ed:


The two-pipe Sys­tem is very con­ve­nient for oper­a­tion in a house in which it is planned to increase the liv­ing space, exten­sion options are pos­si­ble, both up and along the perime­ter of the build­ing. Already at the stage of work, tech­ni­cal errors made dur­ing the design can be eas­i­ly elim­i­nat­ed. Such a scheme is more sta­ble and reli­able than a sin­gle-pipe one.

With all the obvi­ous advan­tages, before choos­ing this type of heat­ing, it is appro­pri­ate to recall the dis­ad­van­tages of a two-pipe sys­tem.

It’s impor­tant to know! The sys­tem is char­ac­ter­ized by a high­er com­plex­i­ty and cost of instal­la­tion and rather cum­ber­some con­nec­tion options.

If you have a com­pe­tent spe­cial­ist at hand, the nec­es­sary tech­ni­cal cal­cu­la­tions have been car­ried out, then the list­ed dis­ad­van­tages are eas­i­ly com­pen­sat­ed by the advan­tages of a two-pipe heat­ing scheme.

As in the case of a sin­gle-pipe sys­tem, the two-pipe option involves the use of a ver­ti­cal or hor­i­zon­tal arrange­ment of pipelines. Ver­ti­cal sys­tem — radi­a­tors are con­nect­ed to a ver­ti­cal ris­er. This type is con­ve­nient for two-sto­ry pri­vate hous­es and cot­tages. Air con­ges­tion is not ter­ri­ble for you. In the case of the hor­i­zon­tal option, the radi­a­tors in each room or room are con­nect­ed to a pipeline locat­ed hor­i­zon­tal­ly. Two-pipe hor­i­zon­tal heat­ing schemes are main­ly designed for heat­ing one-sto­ry build­ings and large res­i­den­tial build­ings with the need for floor-by-floor adjust­ment. Aris­ing air jams are eas­i­ly elim­i­nat­ed by installing Mayevsky cranes on radi­a­tors.


The fig­ure shows a ver­ti­cal two-pipe heat­ing sys­tem. Below you can see what a two-pipe hor­i­zon­tal type sys­tem looks like.

Tra­di­tion­al­ly, radi­a­tors can be con­nect­ed using bot­tom and top wiring. Depend­ing on the tech­ni­cal con­di­tions and the project, the choice of wiring option depends on the own­er of the house. The top wiring is more con­ve­nient. All high­ways can be hid­den in the attic space. The sys­tem cre­ates the cir­cu­la­tion nec­es­sary for a good dis­tri­b­u­tion of the coolant. The main dis­ad­van­tage of a two-pipe heat­ing scheme with an upper wiring option is the need to install a mem­brane tank out­side the heat­ed premis­es. The upper wiring does not allow the intake of tech­ni­cal water for domes­tic needs, as well as con­nect­ing the expan­sion tank to the tank for hot water used in every­day life. This scheme is not suit­able for flat-roofed res­i­den­tial prop­er­ties.


The select­ed type of heat­ing for a pri­vate house should pro­vide all the inhab­i­tants of the res­i­den­tial build­ing with the nec­es­sary com­fort. Save on heat­ing is not worth it. By installing a heat­ing sys­tem in your house that does not meet the para­me­ters of a res­i­den­tial facil­i­ty and domes­tic needs, you run the risk of spend­ing a lot of mon­ey on refur­bish­ment in the future.

Two-pipe or one-pipe heat­ing sys­tem — the choice should always be jus­ti­fied, both from a tech­ni­cal point of view and from an eco­nom­ic one.


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