Ventilation and Air Conditioning Before Apartment Renovation

Bathroom odors, stuffy bedrooms with closed doors, AC “last day” with lines on wallpaper — typical when ventilation and cooling were not planned at renovation start. In Moscow and the region, tighter windows and sound insulation make supply air essential for comfort even with expensive finish.

Profmaster has delivered turnkey apartment renovation in Moscow and the region since 2006. Below: supply and exhaust, AC, drainage, timing before finish, and estimate checks. Wet-zone plumbing is in plumbing and leak protection; bathroom layout in combined bathroom checklist.

In short: comfort systems are MEP — tie them to rough work, electrical, and ceilings, not “after move-in.”

Why plan ventilation before finish

After finish, options get expensive:

• chases in completed walls;
• boxes that steal unplanned height;
• drainage without slope above ceiling;
• supply valves with no wall or glazing penetration;
• outdoor AC unit with no power or management approval.

At project stage fix:

• layout and zoning (bedroom, kitchen-living, office);
• window tightness;
• wet zones and exhaust shafts;
• indoor/outdoor AC locations;
• electrical plan (lines, RCD, panel load);
• ceiling type (stretch, drywall, hybrid).

If you simplify: air and cooling follow the same routes as wiring — draw them on the rough plan.

Budget benchmark — capital renovation calculator; MEP detail — estimate guide.

Supply and exhaust: air balance

Typical flats have bath/kitchen exhaust via building shafts; supply often relied on gaps and window airing. After window replacement, supply drops.

Element	Role	When to plan
Wall/window supply valve	Fresh air without open window	Before slopes and plaster
Supply unit with recovery	Filtered supply, less heat loss	Before ceilings and cabinets
Bath exhaust fan	Remove humidity and odor	Before tile and ceiling, after draft check
Kitchen hood	Grease and steam	Ducted or recirc — before backsplash
Air transfer between rooms	Closed bedroom door	Under-door gap or transfer grilles

Draft check in panel and brick stock

Before bath renovation, test shaft draft: tissue at grille, anemometer, or engineer visit. Weak draft means forced exhaust and correct tie-in — not only new tile.

Symptom	Possible cause	Project action
Bath odor in flat	Reverse draft, bad trap	Fan, sealing, traps
Mirror condensation	High humidity, weak exhaust	Stronger exhaust, supply
Shaft noise	Neighbor fan, shared duct	Backdraft damper, box insulation
Stuffy with closed windows	No supply	Valve or supply unit

More on wet zones — plumbing article and bathroom checklist.

Air conditioning: multi-split or separate units

Choice affects chases, power, and facade.

Scheme	Pro	Con
Split per room	Simple service logic	Multiple outdoor units
Multi-split (one outdoor)	Fewer facade units	Complex lines, higher install
Ducted/cassette (rarer in flats)	Hidden indoor unit	Ceiling, service, noise

On the project mark:

• indoor units — not above bed head, filter access, manufacturer clearances;
• outdoor unit — platform, vibration, service access, management/facade rules;
• refrigerant lines — length, elevation, chase or box;
• drainage — slope, trap, discharge point;
• power — dedicated lines from panel per spec.

In short: AC “after renovation” usually means visible lines and questionable drainage.

Drainage: where and how

Condensate needs constant slope from indoor unit.

1. To sewer — trapped connection (no sewer smell in unit).
2. To facade — approved drain outlet (management/facade rules).
3. To technical zone — tank (rare, needs service).

Drain error	Consequence
No slope in hidden chase	Overflow, mold above ceiling
Sewer tie without trap	Odor in flat
Random discharge	Facade stains, neighbor complaints
No trap access	Service = ceiling opening

Fix lines and drain on drawing before plaster; include in concealed-work act with photos.

Timing vs finish stages

Renovation stage	Ventilation / AC
Project	Zoning, units, supply, electrical load
Rough, chases	Lines, ducts, rough-ins, drain
Electrical	AC lines, fans, panel
Plaster / screed	Close chases after pull
Ceilings	Ducted/cassette units; grilles
Finish	Grilles, valves, exhaust trim
Commissioning	Vacuum, charge, settings per installer

In new builds some rough-ins happen before developer acceptance if scheme changes — see new-build stages.

Outdoor unit mount and refrigerant work follow facade readiness and weather; indoor lines and drain go earlier.

Links to soundproofing and electrical

Penetrations through sound walls are bridges. Coordinate with soundproofing guide:

• avoid straight through-holes across entire system;
• seal flex penetrations;
• do not rigidly tie ducts to slab without damping.

Electrical:

• dedicated line per AC unit;
• protection per design;
• panel capacity for multiple indoor units;
• fan control for exhaust and supply.

Kitchen hood: ducted or recirculating

In open kitchen-living, hood choice affects odors and ceiling layout. Decide before backsplash and wall cabinets.

Type	How it works	When it fits
Ducted	Air to shaft or facade	Good draft, allowed duct, box acceptable
Recirculating	Charcoal filter, return to room	No shaft outlet, management limits
Telescopic + duct	Captures steam at cooktop	Open kitchen with higher demand

Plan in project:

• duct size and route to shaft;
• backdraft damper on shared shaft;
• dedicated electrical line;
• clearance under cabinet before kitchen order.

Weak hood with powerful cooktop overloads supply — stuffy kitchen-living pushes AC harder and condenses on windows. Treat kitchen with kitchen renovation cost and MEP block in estimate guide.

Supply units with recovery: when they make sense

With constant cooling and rare window airing, a supply unit with heat recovery pays off in comfort, not status. Evaluate:

• space in box, closet, or niche (often 15–25 cm depth plus filter access);
• how duct crosses sound-insulated walls;
• panel capacity for fan plus several AC indoor units.

If you simplify: supply is not a “wall vent” — it is a device with filter, noise, and service schedule. Budget it as a separate estimate line with commissioning and filter access.

Approvals and limits in Moscow and region

Clarify before install:

• outdoor unit placement (management, facade committee);
• drain drip restrictions;
• outdoor unit noise/vibration limits;
• supply valve rules in structural panels — engineering check.

Profmaster does not promise permits without site-specific clarification — boundaries are fixed after survey.

Estimate lines

Section	Examples	Check
Supply	Valve, unit, ducts	Brand, capacity, filters
Exhaust	Fan, box, grille	Shaft draft, backdraft damper
AC	Units, lines, drain, start-up	Line length, concealed routing
Electrical	Lines, breakers	Inside “AC” bundle?
Finish trades	Chases, patch, boxes	Often missing in cheap bids
Service	Not always in reno estimate	Filters, drain cleaning

Compare only identical scope — “AC 1 pc” without lines and drain is not comparable to full install.

Typical mistakes

Mistake	Consequence
AC at the end	Lines on wallpaper, no drain
No supply with tight windows	Stuffy air, condensation
Exhaust without draft test	Humidity, mold
Flat drain above ceiling	Leak, neighbor damage
Multiple outdoor units without approval	Management dispute
Chases after wallpaper	Finish redo

Checklist: ventilation and AC before finish

Project

• Zones defined: bedroom, living, kitchen, bath
• Exhaust shaft draft tested
• AC scheme chosen (split / multi)
• Supply and air transfer planned
• Outdoor unit locations agreed

Rough

• Chases and rough-ins before plaster
• Drain with slope and trap (if to sewer)
• Electrical lines from panel
• Photo of routes before cover

Finish and start-up

• Indoor units coordinated with ceilings and cabinetry
• Grilles and valves in finish
• Start-up and condensate check
• Filter and maintenance notes

Estimate

• Supply, exhaust, AC itemized
• Chases and electrical included
• Cross-check estimate guide

When to contact Profmaster

Contact us if:

• you plan capital renovation with tight windows and need supply air;
• you want concealed AC lines and drain before ceilings;
• you combine open kitchen-living with hood and cooling without rework;
• estimates omit comfort systems;
• you want turnkey renovation with one contractor for MEP.

Profmaster:

• plans ventilation and AC at project and survey;
• coordinates with electrical, plumbing, soundproofing;
• prepares estimate with lines, drain, commissioning;
• documents concealed work with photos and stage acceptance;
• has worked in Moscow and the region since 2006.

Services, projects, calculator, contacts — survey and consultation.

Summary

Ventilation and air conditioning are part of renovation engineering, not an afterthought. Supply, exhaust, lines, drain, and power belong before finish — so comfort stays invisible, not chases on wallpaper. Fix decisions in project and estimate — and renovation ends with good air, not another ceiling rebuild.