Underfloor heating from a boiler


Prob­lems with heat­ing res­i­den­tial premis­es dur­ing the cold peri­od are the most rel­e­vant for the bulk of the pop­u­la­tion of our cities. It is not nec­es­sary to hope for a qual­i­ta­tive improve­ment in cen­tral­ized heat­ing. The process of equip­ping house­holds with autonomous heat­ing sys­tems is pro­ceed­ing rather slow­ly. If we talk about city apart­ments in hous­es of old con­struc­tion, then here the sit­u­a­tion gen­er­al­ly looks crit­i­cal. The desire of res­i­dents to equip the apart­ment with addi­tion­al sources of heat­ing comes up against the pro­hi­bi­tions of con­trol­ling orga­ni­za­tions.

Despite the ille­gal­i­ty of instal­la­tion, many res­i­dents of apart­ment build­ings are try­ing to equip their apart­ment with under­floor heat­ing, a heat­ing sys­tem that is rec­og­nized as the most effec­tive today. One desire to make heat­ing floors in your apart­ment is not enough. There are a num­ber of tech­no­log­i­cal chal­lenges that will have to be addressed by those who want to improve the com­fort in their own home.

The instal­la­tion of the heat­ing pipe itself does not raise any spe­cial ques­tions. here it is impor­tant to observe the lay­ing tech­nol­o­gy. Anoth­er thing is the heat­ing source (heater). Gas boil­ers, cen­tral­ized heat­ing and hot water sys­tems, all these con­nec­tion options have a prac­ti­cal imple­men­ta­tion. Against this back­ground, it will be inter­est­ing to con­sid­er from a tech­no­log­i­cal point of view the pos­si­bil­i­ty of con­nect­ing a warm floor from a home boil­er.

Trying to connect a warm floor to a home boiler. Rationale

The cal­cu­la­tion and design of the heat­ing sys­tem for each of us is a solu­tion to the prob­lem, in which there must be two answers — sav­ing mon­ey and achiev­ing the desired effect. In most cas­es, we try to make it eas­i­er for our­selves, to make the heat­ing in our apart­ment as effi­cient as pos­si­ble, while spend­ing a min­i­mum of mon­ey. It is this rea­son that makes us look for alter­na­tive options for con­nect­ing heat­ing cir­cuits. The idea of ​​using an elec­tric boil­er for this pur­pose is not ide­al, how­ev­er, and this option has the right to life.

The main prob­lem is that the oper­a­tion of the elec­tric boil­er in this case will be con­sid­ered inap­pro­pri­ate use, which nat­u­ral­ly can lead to the fail­ure of the heat­ing device ahead of time. Domes­tic boil­ers are designed to pro­vide the inhab­i­tants of the house with hot water for domes­tic pur­pos­es. Attach­ing an addi­tion­al load to an elec­tri­cal appli­ance means fun­da­men­tal­ly chang­ing the man­u­fac­tura­bil­i­ty of the device.

The deci­sion to use a boil­er as a source of heat­ing the coolant can only be prompt­ed by an urgent need and a desire to quick­ly solve the prob­lem of heat­ing a home.

Electric water heaters. Design features

The heat­ing sys­tem, which is based on elec­tric water heat­ing, is noth­ing spe­cial. A boil­er is a device in which water is heat­ed by elec­tric­i­ty. Accord­ing to the prin­ci­ple of oper­a­tion, boil­ers are divid­ed into two types:

  • accu­mu­la­tive;
  • flow­ing.

For mod­els with a stor­age tank, the main struc­tur­al ele­ment is a heat­ing ele­ment that pro­vides water heat­ing. Heat­ing ele­ments are usu­al­ly installed in a stor­age tank where tap water enters. The mode of turn­ing on and off the heat­ing ele­ments is pro­vid­ed by automa­tion.

On a note: From a tech­no­log­i­cal point of view, the stor­age boil­er is more like a ther­mos. In the inner case, water is heat­ed. The out­er case of the device per­forms pro­tec­tive func­tions, pro­tect­ing the inner tank from mechan­i­cal dam­age and reduc­ing the amount of heat loss. The space between the hous­ings is filled with insu­lat­ing mate­r­i­al (min­er­al wool or expand­ed poly­styrene).


Dur­ing nor­mal oper­a­tion of the device, depend­ing on the pow­er of the heat­ing ele­ments and the vol­ume of the tank, the water is heat­ed with­in 2–3 hours. The water in the boil­er, due to the dou­ble case, keeps the set tem­per­a­ture for a long time (12–24 hours). The dia­gram shows the inter­nal struc­ture of the stor­age boil­er, which is con­nect­ed to an autonomous under­floor heat­ing sys­tem.

Due to its high per­for­mance para­me­ters, the stor­age boil­er is by its design best suit­ed to ensure the oper­a­tion of under­floor heat­ing in your apart­ment.

If we talk about an elec­tric flow-type boil­er, then here the cir­cuit dia­gram is com­plete­ly dif­fer­ent. There is no stor­age tank, and the whole process takes place inside a com­pact flask, which is equipped with a heat­ing ele­ment. Unlike stor­age devices, flow boil­ers are equipped with heat­ing ele­ments of greater pow­er (6–20 kW), capa­ble of pro­vid­ing inten­sive heat­ing of the water flow in a short peri­od of time.

Impor­tant! The water in the flow heater is heat­ed to the required tem­per­a­ture in a mat­ter of min­utes (30–120 sec­onds), so the load on the home elec­tri­cal net­work is rapid­ly increas­ing.

How to choose the right heater


For under­floor heat­ing, a flow-type boil­er can be con­sid­ered unsuit­able. It is not worth going into the details of this deci­sion. There is one obvi­ous fact — a large con­sump­tion of elec­tric­i­ty!

Let’s dwell on the stor­age type boil­ers. When choos­ing a mod­el, you should pay atten­tion to the pow­er of the device. It is this para­me­ter that deter­mines the inten­si­ty and speed of heat­ing tap water. The pow­er of a water heat­ing boil­er is direct­ly relat­ed to the amount of elec­tric­i­ty con­sumed. As a rule, house­hold boil­ers have a capac­i­ty of 1.5–3 kW.

On a note: There are elec­tric boil­ers on sale, the pow­er of which is much high­er than the pro­posed para­me­ters (6–10 kW). Such devices are spe­cial­ly ori­ent­ed to work in com­bi­na­tion with heat­ing sys­tems. The only dis­ad­van­tage of such mod­els is the high pow­er con­sump­tion. Are you ready for it, buy it!

After pow­er, pay atten­tion to the vol­ume of the stor­age tank. The more hot water you get, the less often there will be peri­od­ic switch­ing on of the device for heat­ing the water cir­cu­lat­ing in the water cir­cuit. For house­hold appli­ances, the vol­ume of tanks is usu­al­ly 50–100 liters. Indus­tri­al boil­ers used for the heat­ing sys­tem have a stor­age tank vol­ume of 250–300 liters.

Boil­ers spe­cial­ly designed to work with heat­ing sys­tems have some dif­fer­ences from house­hold appli­ances. The main dif­fer­ences are as fol­lows:

  • such devices have a dif­fer­ent arrange­ment of inlet and out­let noz­zles;
  • sec­tion of outlet/entrance open­ings;
  • large stor­age tank.

In the first case, we are talk­ing about the fun­da­men­tal loca­tion of the noz­zles inlets and out­lets of water. The cold water inlet is at the bot­tom, while the hot water out­let is at the top of the tank. Thanks to this arrange­ment of pipes, the max­i­mum pos­si­ble cir­cu­la­tion of water in the heat­ing sys­tem is achieved. With regard to the diam­e­ter of the inlet and out­let, here the accept­able diam­e­ter is at least 2 mm.

For ref­er­ence: in domes­tic boil­ers, the holes are ¾ inch in diam­e­ter.

The pow­er of the water heat­ing appli­ance is deter­mined in accor­dance with the tra­di­tion­al para­me­ters 1 kW — 10 m2 heat­ed area. There­fore, house­hold stor­age boil­ers for heat­ing res­i­den­tial premis­es are of lit­tle use. They can be used for installing under­floor heat­ing in lim­it­ed spaces (bath­room).

Design features of underfloor heating based on an electric boiler


When design­ing your own heat­ing sys­tem, take into account:

  • the num­ber of branch­es and the length of the pipeline. The more water cir­cuits you have, the longer their length, the slow­er hot water will cir­cu­late through the sys­tem;
  • if the boil­er pow­er cor­re­sponds to the size of the heat­ed area at the low­er thresh­old, you may encounter a drop in the effi­cien­cy of water heat­ing over time. The way out of the sit­u­a­tion is to pur­chase a boil­er with a pow­er reserve of 20%.
  • con­stant care of the con­di­tion of the water heater. Reg­u­lar clean­ing of the stor­age tank and heat­ing ele­ments from scale will allow you to keep the pipes of the water-heat­ed floor in good con­di­tion and increase the life of the heat­ing device.

Com­pli­ance with all of the above fac­tors will allow you to pro­ceed direct­ly to the instal­la­tion of the under­floor heat­ing sys­tem, then con­nect­ing it to the boil­er. Boil­er instal­la­tion is usu­al­ly done in the bath­room or next to the room that will be heat­ed. To increase the per­for­mance of your heat­ing sys­tem, you can install a cir­cu­la­tion pump. Thanks to this device, you can achieve unin­ter­rupt­ed sup­ply of coolant to the water cir­cuit.

Impor­tant! It is bet­ter to entrust the con­nec­tion of the cir­cu­la­tion pump to spe­cial­ists who have an idea about the oper­a­tion of this device.


Assess­ing the com­plex­i­ty and effi­cien­cy of the “warm floor from the boil­er” heat­ing sys­tem, you can already in the process of oper­a­tion. Of course, this method of heat­ing has its advan­tages. Instal­la­tion of the entire heat­ing sys­tem is quite sim­ple. Lay the water cir­cuit, con­nect to the heater and final­ly install the boil­er, you can do it your­self. The main thing is to strict­ly fol­low the tech­nol­o­gy and instruc­tions. Do not dis­count the low cost of such a heat­ing sys­tem. Boil­ers cost an order of mag­ni­tude less than elec­tric heat­ing boil­ers.

How­ev­er, this sys­tem also has its draw­backs. The most impor­tant and tan­gi­ble is the high cost of elec­tric­i­ty. With the con­stant oper­a­tion of under­floor heat­ing dur­ing the heat­ing sea­son, inten­sive con­sump­tion of hot water for domes­tic pur­pos­es, your ener­gy costs will increase sig­nif­i­cant­ly. The best option for using such a heat­ing sys­tem is heat­ing a bath­room or a small coun­try house.


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