Warm floors in a wooden house as the main heating

The idea of ​​installing under­floor heat­ing in pri­vate homes is very pop­u­lar in our coun­try. If, with con­ven­tion­al radi­a­tors, warm air ris­es, leav­ing the space near the floor unheat­ed, then using this tech­nol­o­gy, the entire room warms up com­plete­ly. Walk­ing on such a sur­face is much more pleas­ant, espe­cial­ly if cold fin­ish­ing mate­ri­als, such as tiles, are laid on the floor.


The idea of ​​installing under­floor heat­ing in pri­vate homes is very pop­u­lar in our coun­try. If, with con­ven­tion­al radi­a­tors, warm air ris­es, leav­ing the space near the floor unheat­ed, then using this tech­nol­o­gy, the entire room warms up com­plete­ly. Walk­ing on such a sur­face is much more pleas­ant, espe­cial­ly if cold fin­ish­ing mate­ri­als, such as tiles, are laid on the floor.

Underfloor heating from a gas boiler.
Under­floor heat­ing from a gas boil­er.

Heat­ed floors in a wood­en house as the main heat­ing are not used very often due to a num­ber of rea­sons. First of all, these are dif­fi­cul­ties with the cre­ation of a con­crete screed, which will dis­trib­ute heat in a qual­i­ty man­ner and trans­fer it to the sur­round­ing space. Dry screed copes with this task much worse. There­fore, this sys­tem is often used as addi­tion­al heat­ing to the exist­ing one to cre­ate greater com­fort.

A water heat­ed floor is more often con­nect­ed to gas boil­ers than to elec­tric or sol­id fuel ones. Mod­ern equip­ment used for autonomous heat­ing is quite capa­ble of ensur­ing the nor­mal func­tion­ing of this sys­tem. Even a per­son who does not have much expe­ri­ence in the con­struc­tion indus­try can make a water-heat­ed floor from a gas boil­er in a wood­en house with their own hands. The main thing that is required for effi­cient oper­a­tion is to car­ry out the cor­rect hydraulic and ther­mal cal­cu­la­tions, as well as to make a com­pe­tent instal­la­tion.

Underfloor heating device from a gas boiler

The main ele­ments of the under­floor heat­ing sys­tem in a wood­en house from gas heat­ing are as fol­lows:

  1. Gas boil­er.
  2. Injec­tion pump.
  3. Con­nect­ing fit­tings and valves.
  4. The main pipeline that dis­trib­utes warm water through­out the premis­es.
  5. Floor pipeline mount­ed on the sub­floor.
  6. Automa­tion.
  7. Col­lec­tor.

Choosing a gas boiler

If the instal­la­tion of a warm floor is planned in a house with a large num­ber of premis­es of a large area, a dou­ble-cir­cuit boil­er with a large capac­i­ty will be the best choice. Such equip­ment per­forms two tasks at once: it pro­vides hot water sup­ply and home heat­ing. Dou­ble-cir­cuit floor boil­ers should be installed in a sep­a­rate room — a boil­er room, the area of ​​u200bu200bwhich is from 4 m² for devices with a pow­er of up to 30 kW.

Advice. A sin­gle-cir­cuit boil­er can also be used for under­floor heat­ing, but in this case it will be nec­es­sary to install an addi­tion­al indi­rect heat­ing boil­er for hot water sup­ply, which can be placed in the same room.

Single-circuit and double-circuit gas boilers.
Sin­gle-cir­cuit and dou­ble-cir­cuit gas boil­ers.

If the house is small, or there is no pos­si­bil­i­ty to equip a sep­a­rate room for a boil­er room, you can choose a wall-mount­ed boil­er with more com­pact dimen­sions. If you cor­rect­ly cal­cu­late its pow­er (for this equip­ment it ranges from 7–30 kW), then it will be able to ensure the effi­cient oper­a­tion of the under­floor heat­ing sys­tem. The place­ment of such boil­ers is allowed in any premis­es, includ­ing kitchens and bath­rooms, it is only nec­es­sary to equip a chim­ney that opens into the cen­tral or out­side.

Pipes for underfloor heating system

Cop­per pipes, which have a long ser­vice life, are con­sid­ered ide­al for cre­at­ing under­floor heat­ing. Due to the high qual­i­ty, their cost is quite high and not every­one can afford. There­fore, more often in hous­es they use met­al-plas­tic, polypropy­lene and PEX pipes.

Polypropy­lene prod­ucts are quite high qual­i­ty, but they are not very suit­able for a warm floor, as they have insuf­fi­cient flex­i­bil­i­ty, and there­fore the turns have to be made at a suf­fi­cient­ly large dis­tance from each oth­er.

Met­al-plas­tic pipes, which are resis­tant to dam­age, are very pop­u­lar, and alu­minum inside pro­vides good ther­mal con­duc­tiv­i­ty. At the same time, the prod­ucts are char­ac­ter­ized by an afford­able price.

Underfloor heating from plastic pipes.
Under­floor heat­ing from plas­tic pipes.

PEX pipes are low-cost prod­ucts made of spe­cial­ly mod­i­fied poly­eth­yl­ene, char­ac­ter­ized by high strength and dura­bil­i­ty. It should be borne in mind that these prod­ucts must be rigid­ly fixed in the screed, since, when heat­ed, they tend to straight­en up and take their orig­i­nal shape.

Advice. Pur­chase pipes that are specif­i­cal­ly designed for use in water sys­tems and are labeled accord­ing­ly. Such prod­ucts eas­i­ly with­stand heat­ing up to 95 C and pres­sure up to 10 bar.

The procedure for installing underfloor heating from gas heating

Now let’s talk about how to prop­er­ly install a gas boil­er and a warm water floor in a wood­en house so that the sys­tem works cor­rect­ly and as effi­cient­ly as pos­si­ble. The whole pro­ce­dure is divid­ed into sev­er­al stages, each of which is of no small impor­tance. It all starts with the prepa­ra­tion of the foun­da­tion.

Foundation preparation

The sub­strate must be care­ful­ly pre­pared and cleaned. Per­mis­si­ble dif­fer­ences per meter of length are 1 cm, if this fig­ure is greater, it is nec­es­sary to align. It is impor­tant not to for­get about the hydro and ther­mal insu­la­tion of the sub­floor. As the lat­ter, it is best to use basalt fiber or expand­ed poly­styrene. For the first floor of the house, the insu­la­tion lay­er should be at least 10 cm, for the upper floors 3–5 cm will be enough.


An ide­al option for a water-heat­ed floor is a cement filler screed. In some cas­es, it can be done on the first floors of wood­en hous­es, but more often you have to be con­tent with dry options. They are car­ried out accord­ing to two tech­nolo­gies — rack and mod­u­lar. The lat­ter is the most pop­u­lar and involves the man­u­fac­ture of spe­cial mod­ules to which heat-dis­trib­ut­ing plates are attached, and between which heat­ing pipes are locat­ed. The mate­r­i­al for the man­u­fac­ture of mod­ules can be very dif­fer­ent — chip­board, GVL-plates, poly­styrene and oth­ers. Mod­ules are cut from sol­id sheets after the pipe out­line is applied to them.

Advice. Today, in hard­ware stores, you can buy ready-made mod­ule sys­tems for under­floor heat­ing, which are ful­ly pre­pared for instal­la­tion and do not require pro­cess­ing. Such kits may also include met­al plates, pipes and all nec­es­sary fas­ten­ers. All this allows to great­ly facil­i­tate and speed up the process of installing a warm floor. The dis­ad­van­tage is the high cost of such prod­ucts, which not every­one can afford.

Choosing a way to lay water pipes

There are three main ways of lay­ing under­floor heat­ing pipes:

  • “Snake”.
  • “Dou­ble snake”.
  • “Spi­ral”.
Contours of a heat-insulated floor.
Con­tours of a heat-insu­lat­ed floor.

The “snake” is quite sim­ple to install, but has a sig­nif­i­cant draw­back: mov­ing along such a con­tour, the water has time to cool down, which caus­es cold spots to form on the floors. For this rea­son, it is more often used in rooms with a small area. “Dou­ble snake” is a more opti­mal option in which heat is dis­trib­uted more even­ly. But it has a sig­nif­i­cant draw­back, which is also present in the first option: instal­la­tion is com­pli­cat­ed by the fact that the angle of rota­tion of the pipes reach­es 180 degrees.

“Spi­ral” — the most con­ve­nient cir­cuit, in which the pipes are locat­ed along the perime­ter of the room from the walls to the cen­ter, and upon reach­ing the mid­dle, they turn back in the same way to close. With this arrange­ment, cold zones on the floor will be com­plete­ly absent. The tech­nol­o­gy is ide­al for large spaces.

“Snake” and “Spi­ral” can be com­bined depend­ing on the con­fig­u­ra­tion of the premis­es, which have a vari­ety of pro­tru­sions or recess­es.

Connecting a gas boiler to a warm floor

We looked at how to make a warm floor in a wood­en house with gas heat­ing, now we need to talk about con­nect­ing the sys­tem to the boil­er itself.

Collector connection diagram

Collector scheme for connecting a warm floor.
Col­lec­tor scheme for con­nect­ing a warm floor.

To orga­nize a warm water floor in a house with wood­en floors from a gas boil­er with your own hands, you can use the col­lec­tor con­nec­tion scheme. In this case, it is nec­es­sary to con­nect the pipes of the heat­ing sys­tem to the boil­er through a col­lec­tor. The con­nec­tion takes place after lay­ing the floor and mount­ing the man­i­fold cab­i­net.

Think in advance of a place for a col­lec­tor cab­i­net, where it will be con­ve­nient to start the sup­ply and return pipes. They are joined by the side out­lets of the col­lec­tor, on which stop­cocks were pre­vi­ous­ly installed.

Advice. It is bet­ter to pur­chase a man­i­fold kit that includes shut-off valves on all out­lets for hot water pipes. Thanks to this, if nec­es­sary, it will be pos­si­ble to turn off only one cir­cuit, while the rest of the sys­tem com­po­nents will con­tin­ue to work.

Cranes, pipes and man­i­folds are con­nect­ed by com­pres­sion fit­tings. Con­nec­tion of pipes with water to the col­lec­tor can be car­ried out with spe­cial con­nec­tors, con­sist­ing of a clamp­ing ring, a nut and a sup­port sleeve. When it is nec­es­sary to con­nect dif­fer­ent diam­e­ters, adapters are used.

Connection of collectors with stopcocks.
Con­nec­tion of col­lec­tors with stop­cocks.

The sim­plest design con­sists of con­ven­tion­al col­lec­tors with shut-off valves. The return and sup­ply are con­nect­ed to pipes and taps, car­ri­er pipes and col­lec­tors are also con­nect­ed. This scheme is eas­i­ly and quick­ly mount­ed, but is the least con­ve­nient.

In a more com­plex sys­tem, in addi­tion to shut-off valves, there is a three-way mix­er, a drain cock, an air vent and a cir­cu­la­tion pump. Shut-off valves can be replaced by con­trol valves equipped with a paraf­fin bulb, the pur­pose of which is to deter­mine the capac­i­ty of the valve.

The mix­ing pump is mount­ed between the man­i­fold and the sup­ply pipe. Its third out­put goes to the return line in front of the return pipe. Due to this, the equip­ment takes water with a low tem­per­a­ture and trans­fers it to the sup­ply.

Connection with mixing valve

If the flow is good enough, a three-way valve can be used instead of a pump. Its instal­la­tion is car­ried out in the same way as the pump­ing and mix­ing unit at the out­let of the return.

Below is a dia­gram show­ing what the sys­tem looks like.

Three way mixing valve.
Three way mix­ing valve.

Connection with a circulation pump

If the pres­sure is not good enough, and the mix­er is not need­ed, a cir­cu­la­tion pump is used. It is mount­ed on the return line, since when arrang­ing the sup­ply, it will take addi­tion­al water from the heat­ing sys­tem, and less heat will remain in the radi­a­tors.

Scheme of a circular pump.
Scheme of a cir­cu­lar pump.

From this mate­r­i­al, you learned how to make a warm water floor on a wood­en base from a gas boil­er and you can make all the nec­es­sary con­nec­tions your­self. How­ev­er, you need to remem­ber such an impor­tant fac­tor as safe­ty pre­cau­tions. In no case do not neglect the require­ments that apply to this equip­ment, and strict­ly fol­low the oper­at­ing instruc­tions. The equip­ment must be equipped with a high-qual­i­ty automa­tion sys­tem, which, in the event of a vio­la­tion of tech­no­log­i­cal process­es, will shut down. Do not neglect the annu­al inspec­tion and main­te­nance of the gas boil­er by spe­cial­ized ser­vices.


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