How to make ventilation in the basement: scheme, materials, calculation


vents in an old basement

The base­ment is an inte­gral part of a mod­ern pri­vate house or cot­tage. It serves to accom­mo­date com­mu­ni­ca­tions of heat­ing and water sup­ply sys­tems in it, and can be used as a garage, work­shop or veg­etable store. In any case, the base­ment needs to main­tain a giv­en lev­el of tem­per­a­ture and humid­i­ty. Damp­ness adverse­ly affects the safe­ty of agri­cul­tur­al prod­ucts, leads to the appear­ance of mold, destroys the walls of the house and neg­a­tive­ly affects oth­er objects. Prop­er­ly equipped base­ment ven­ti­la­tion will help to solve this prob­lem.

Pros and cons

We note the pos­i­tive aspects of the use of ven­ti­la­tion sys­tems in the base­ment and base­ment:cellar ventilation pipes

  • Com­fort­able micro­cli­mate in the housethere is no feel­ing of damp­ness on the first floor;
  • Pos­si­bil­i­ty to build a stor­age roomwhich main­tains a con­stant tem­per­a­ture and mois­ture con­tent in the air;
  • Increas­es the ser­vice life of load-bear­ing struc­tures res­i­den­tial build­ing or cel­lar, espe­cial­ly if they are made of wood;
  • The oper­a­tion of gas and heat­ing equip­ment is not pos­si­ble in an unven­ti­lat­ed room for safe­ty rea­sons;
  • Mold spores will nev­er grow in a dry base­mentthat cause colds, aller­gies and asth­ma.


All types of ven­ti­la­tion are divid­ed into sev­er­al types, depend­ing on its pur­pose, the com­plex­i­ty of the arrange­ment and the prin­ci­ple of oper­a­tion. But the prin­ci­ple of oper­a­tion of any of them will be based on the laws of physics on the move­ment of air mass­es. Cold air goes down and warm air goes up.

Natural supply ventilation

The sim­plest, air­flow sys­tem in the foun­da­tion or base­ment. It is equipped at the stage of build­ing a house and is a small hole in the upper part of the base­ment.

If the base­ment is below ground lev­el, then the hood is equipped with plas­tic or asbestos-cement pipes with a diam­e­ter of 10–15 cm. They are brought out above the sur­face to a height of 30 cm and cov­ered with bars from debris and rodents. This method is nat­ur­al and depends on fluc­tu­a­tions in street tem­per­a­ture, wind strength, and humid­i­ty.

vent with grate

When cal­cu­lat­ing its through­put, 1/400 of the total area of ​​u200bu200bthe base­ment is tak­en — this is how we get the total area of ​​u200bu200ball the ducts.

Open­ings should be locat­ed on the lee­ward side, the least exposed to pre­cip­i­ta­tion. Hous­es with a com­plex foun­da­tion shape and locat­ed in low-lying places can have up to one hole for every 3–4 meters. We close the vents with grat­ings from the out­side.

This inex­pen­sive option is well suit­ed for ven­ti­lat­ing garages and non-res­i­den­tial base­ments, or as an addi­tion to the main ven­ti­la­tion sys­tem.

Natural exhaust ventilation

supply and exhaust ventilation schemeSup­ply and exhaust type. For prop­er oper­a­tion, you will need to install two pipes for ven­ti­la­tion, and the sup­ply and exhaust ven­ti­la­tion device looks like this.

  • The first pipe is locat­ed under the very ceil­ing of the base­ment and is designed to expel warm air. We place the exhaust pipe as high as pos­si­ble, prefer­ably at the lev­el of the roof ridge. This is nec­es­sary to ensure good trac­tion. The part of the pipe that is in the open air must be insu­lat­ed to pre­vent freez­ing in the win­ter and cov­ered with a visor from pre­cip­i­ta­tion.
  • The sec­ond pipe for the inflow of fresh air is locat­ed at a height of 30–40 cen­time­ters from the floor lev­el, and we place its entrance on the street a meter above the ground and cov­er it with a grate. Con­vec­tion will occur due to the tem­per­a­ture dif­fer­ence between the out­door and base­ment air. Such a sys­tem will work most effi­cient­ly when the sup­ply chan­nels are sep­a­rat­ed on dif­fer­ent sides of the base­ment.

The dis­ad­van­tage of all nat­ur­al exhaust ven­ti­la­tion sys­tems is one — it is depen­dent on weath­er con­di­tions and pre­vail­ing winds. It will not work if the tem­per­a­ture in the base­ment and on the street is equal.


It is used if nat­ur­al sup­ply ven­ti­la­tion can­not cope or there is no phys­i­cal pos­si­bil­i­ty to use it. Usu­al­ly used in the fol­low­ing cas­es:

  • Base­ment area from 40 m² or has sev­er­al rooms iso­lat­ed from each oth­er;
  • High humid­i­ty rooms, when the con­den­sate in the exhaust duct freezes in win­ter and impairs the per­me­abil­i­ty of air mass­es;
  • The archi­tec­ture of the house does not pro­vide for high ven­ti­la­tion pipes;
  • The base­ment is equipped with a sauna, cafe, gym, work­shop or oth­er source of bad odors.

The device of forced sup­ply and exhaust ven­ti­la­tion has a sys­tem of chan­nels and fans that dis­till air.

The main con­di­tion is to make the air con­stant­ly cir­cu­late., which is ensured by the syn­chro­nous oper­a­tion of exhaust and sup­ply fans. Their num­ber is cal­cu­lat­ed depend­ing on the vol­ume of the cel­lar or base­ment and the capac­i­ty of the air ducts.

Supply and exhaust ventilation with heat recovery

For a base­ment floor where per­ma­nent res­i­dence is planned, it is not enough to sim­ply install a forced ven­ti­la­tion sys­tem. The room must be insu­lat­ed and water­proofed. The issue of heat­ing and heat­ing is also solved.

Increas­ing­ly, sup­ply and exhaust with heat recov­ery is built into such schemes.

Already well-heat­ed air enters the exhaust pipe, and in order not to throw ready-made calo­ries into the atmos­phere, the air is passed through a spe­cial ceram­ic heat exchang­er. When heat­ed, it gives off heat to fresh air. The air streams do not inter­sect. The effi­cien­cy of such a device is 50–90%, depend­ing on the design of the heat exchang­er. All heat recu­per­a­tors are very reli­able, do not require addi­tion­al main­te­nance and can serve for decades.

SPVVR units with heat recovery

It is equipped with mois­ture traps, dust fil­ters, sen­sors that con­trol humid­i­ty and air tem­per­a­ture. For a res­i­den­tial area, these fig­ures lie in the range of 50–65% rel­a­tive humid­i­ty and 18–220C. Such sys­tems are most often found in “smart homes”, and their instal­la­tion is com­pli­cat­ed and should only be car­ried out by pro­fes­sion­als.

Supply and exhaust ventilation device

Now let’s fig­ure out how to make ven­ti­la­tion in the base­ment. The eas­i­est way would be to make ven­ti­la­tion in the cel­lar or base­ment of the sup­ply and exhaust type or forced.

Let’s do the cal­cu­la­tion first.

For 1 m² of area there should be 25 cm² of the cross sec­tion of the duct.

With an increase in ceil­ing height or humid­i­ty, the diam­e­ter of the duct increas­es. The wood­en box can be divid­ed into two halves for sup­ply and exhaust ven­ti­la­tion, but it is best to use plas­tic pipes or cor­ru­gat­ed met­al box­es.

Wood­en ven­ti­la­tion parts must be treat­ed against mold and paint­ed.

The sup­ply and exhaust ven­ti­la­tion device can be sup­ple­ment­ed with a deflec­tor on the roof of the house. It will cre­ate addi­tion­al vac­u­um in the pipe and improve the out­put of warm air.stainless steel roof cap

A con­trolled forced sys­tem will be much more effi­cient with com­pa­ra­ble labor costs. To do this, we need spe­cial duct fans that oper­ate on a volt­age of 36 V. This fea­ture is asso­ci­at­ed with the cat­e­go­ry of all base­ments that allow the use of only such cur­rents.

There­fore, a trans­former is installed in the elec­tri­cal pan­el that low­ers the volt­age from 220 V to 36 V. And the wiring must be laid in cable chan­nels. These and oth­er rules can be found in SNiP 41–01-2003 heat­ing, ven­ti­la­tion and air con­di­tion­ing.

For small rooms, only one such fan per exhaust arm will suf­fice. The influx of fresh air will be car­ried out due to rar­efac­tion in the base­ment. But the effi­cien­cy of the sys­tem will be much high­er if you install a sec­ond sup­ply pump and com­bine their work on one con­trol pan­el.prefabricated blocks with recuperation

Now on sale you can find pro­gram­ma­ble con­trol pan­els with tem­per­a­ture and humid­i­ty sen­sors, and the duct fans them­selves are avail­able in all sizes and are com­pat­i­ble with almost any ven­ti­la­tion ducts. For con­ve­nience, they are already built into the case, have a pro­tec­tive grille and replace­able fil­ters.

It is prefer­able to use PVC as pipes for ven­ti­la­tion ducts in your own house. They are strong and light enough to attach to walls and ceil­ings with stan­dard wall plugs. They are not afraid of mois­ture and tem­per­a­ture changes, and the cost is low­er than steel struc­tures.

Con­den­sa­tion will always form in the exhaust ven­ti­la­tion ducts, which must be removed peri­od­i­cal­ly. To do this, you can pro­vide a spe­cial hole for drain­ing water. Excess mois­ture leads to cor­ro­sion of met­al struc­tures and increas­es the like­li­hood of freez­ing of the air duct in win­ter. If this hap­pens, then you should def­i­nite­ly clean and defrost the chan­nel.

Health check

Deter­min­ing air cir­cu­la­tion is quite sim­ple. To do this, you can use the open flame of an alco­hol burn­er or can­dle, or attach a paper sheet to the hole in the exhaust chan­nel. A good hood will secure­ly hold the sheet. The ther­mome­ter installed in the area of ​​the sup­ply air duct will not dam­age either.

checking the system with a piece of paper

The fol­low­ing signs speak of poor ven­ti­la­tion of the base­ment, garage:

  • The appear­ance of con­den­sa­tion on the wallsand the humid­i­ty is over 95%. Per­mis­si­ble max­i­mum humid­i­ty for stor­ing blanks and crops is 85–90% at a tem­per­a­ture of 3–40C. For res­i­den­tial premis­es, a garage, humid­i­ty indi­ca­tors should not exceed 40–50%;
  • Mold and fun­gi on walls and ceil­ings;
  • Bad smell indoors and heavy stale air;
  • Sud­den tem­per­a­ture changes they talk about an incor­rect device for sup­ply and exhaust ven­ti­la­tion or errors in cal­cu­lat­ing the cross sec­tion of chan­nels;
  • In warm weath­er, con­den­sa­tion may not be notice­able, but in win­ter the walls will be abun­dant­ly cov­ered with frost;
  • Cel­lars with veg­eta­bles can accu­mu­late car­bon diox­ide. You can deter­mine it by an extin­guished can­dle or match. In this case, it is nec­es­sary to open all dampers and ven­ti­late dur­ing the day, with­out going down into the room with­out pro­tec­tive equip­ment.

The instal­la­tion of ven­ti­la­tion sys­tems will be much more effec­tive if, togeth­er with it, mea­sures are tak­en to main­tain the micro­cli­mate:

  • Peri­od­ic ven­ti­la­tion with the open­ing of all doors and hatch­es. This require­ment is espe­cial­ly rel­e­vant for cel­lar own­ers. It is best to do this in the sum­mer, and get all the wood­en items from the cel­lar;
  • Treat walls reg­u­lar­ly lime or spe­cial com­pounds. They will pro­tect against the appear­ance of mold and unpleas­ant odors in the room. An approx­i­mate recipe for such a com­po­si­tion: for a buck­et of water 3 kg of lime and 50 g of cop­per sul­fate;
  • With excess mois­ture in the air, you can fight with a box of sand, saw­dust, salt, quick­lime. Peri­od­i­cal­ly, the box is tak­en out and thor­ough­ly dried in the sun. In the cel­lar, you can leave the hole unlocked, and cov­er it with old blan­kets or mat­tress­es to improve air cir­cu­la­tion;
  • It helps to install an addi­tion­al heat source (small stove, bra­zier, heater, lamp) or just a burn­ing can­dle;
  • Water­proof­ing the base­ment or cel­lars with bitu­mi­nous com­pounds;
  • Install adjustable dampers for sup­ply and exhaust ven­ti­la­tion. With their help, it will be pos­si­ble to exclude drafts and freez­ing of the base­ment in win­ter;
  • If the cel­lar is locat­ed in the garage, then it should have a sep­a­rate ven­ti­la­tion sys­tem. The increased humid­i­ty of the veg­etable cel­lar is con­traindi­cat­ed for the car;
  • Install a reg­u­lar home fan.

How much does ventilation cost

Pro­vid­ing a good micro­cli­mate in the base­ment is inex­pen­sive. Sim­ple options can be made from con­struc­tion waste and impro­vised mate­ri­als, more com­plex ones will require addi­tion­al invest­ments.

The fol­low­ing fac­tors will affect the cost of the entire sys­tem:

  • The area of ​​u200bu200bthe base­ment and the height of the entire build­ing. Accord­ing to these para­me­ters, the num­ber and size of air ducts are cal­cu­lat­ed, which will be a sig­nif­i­cant part of the entire project;
  • Air box mate­r­i­al. PVC is cheap­er, but has lim­i­ta­tions in size and max­i­mum pipe diam­e­ter. Gal­va­nized steel is more reli­able and allows ven­ti­la­tion of any degree of com­plex­i­ty and con­fig­u­ra­tion, but is much more expen­sive, heav­ier and may require spe­cial equip­ment;
  • Degree of automa­tion (a sim­ple duct fan costs from 20 dol­lars, a switch from 14$);
  • The pres­ence of com­plex and expen­sive addi­tion­al devices — split sys­tems, recu­per­a­tors, dehu­mid­i­fiers, hygrom­e­ters and sen­sors (the cost of such a turnkey sys­tem can exceed 1000 $);

Ven­ti­la­tion in the base­ment is impor­tant both for the safe­ty of the food stored there and for the well-being of the whole house. The sim­plest options can be made inde­pen­dent­ly or laid down at the con­struc­tion stage. More com­plex types of ven­ti­la­tion will require spe­cial skills and expe­ri­ence. In any case, this sys­tem should always be ser­vice­able and ser­viced in a time­ly man­ner.

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