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AC condensate drainage: the detail that causes most disputes
A cooling AC produces litres of condensate per day, and where that water goes is the most common source of AC conflicts in Latvian apartment buildings. The three acceptable solutions are a gravity drain line with continuous slope to a suitable discharge point, a condensate pump where gravity is impossible, or (in heating mode) managed drip that cannot ice a walkway. Dripping onto the facade or a neighbour's window is how installations end up in dispute.
Key takeaways
- A split unit in Latvian summer humidity produces roughly 1–3 litres of condensate per hour of active cooling — this is a plumbing question, not a drip.
- Gravity drainage needs continuous slope along the whole line — a single sag creates a water trap, then overflow from the indoor unit onto your wall.
- Water onto the facade, a walkway or a neighbour's window/balcony is the #1 trigger for complaints to the building manager — managers' own AC rules address condensate explicitly.
- Where gravity is impossible (unit far from any discharge point, line must run upward), a condensate pump solves it — small, built into the line, a standard priced extra.
- In winter heating mode the OUTDOOR unit drips during defrost — plan for that water too, especially above entrances and walkways where it becomes ice.
Why a few litres of water matter so much
Cooling works by condensing moisture out of room air — in a humid Latvian July, 1–3 litres per hour of active cooling. Over a hot week that is a bathtub of water leaving your indoor unit, and it all goes wherever the drain line points.
That is why condensate appears explicitly in building managers’ AC rules (RNP’s guidance among them), in every serious installer’s quoted scope, and in what a proper quote contains. It is also the most common way an otherwise legal installation turns into a neighbour dispute.
The three acceptable solutions
| Solution | When | Watch out for |
|---|---|---|
| Gravity drain line | Discharge point reachable with continuous downward slope | Sags and rising sections = water trap = overflow indoors |
| Condensate pump | No gravity path (unit far from discharge, line must climb) | Slight tick noise; needs power; add to quote explicitly |
| Managed outdoor drip | Only where water harms nothing — greenery below, no facade contact, nobody passes | Almost never OK on street-facing walls or above walkways |
Discharge points used in Latvian buildings, in order of preference: a sewerage connection with a trap (kitchen/bathroom nearby), a rainwater downpipe where the building permits it, or open ground/greenery. Your manager’s AC procedure usually names which of these your building accepts.
Getting the line right
- Slope: continuous fall the whole way — installers work to roughly 1–2 cm per metre minimum. “Mostly downhill” is not downhill.
- Insulate the drain line where it runs through cold zones; condensate in a freezing service shaft becomes an ice plug.
- Trap at a sewerage connection, or summer sewer smells arrive through the AC.
- Route through the same wall penetration as the refrigerant line where possible — one hole, properly sealed and sloped outward.
- Test on commissioning: pouring a cup of water into the drain pan and seeing it emerge at the discharge point takes a minute — ask for it.
Winter: the other condensate
In heating mode the water appears at the outdoor unit: defrost cycles melt ice off the coil several times a day in freezing weather. Under a unit mounted above an entrance or walkway, that water is an ice patch by evening. If the outdoor unit serves heating, mount it where defrost water can drip harmlessly or fit a heated drip tray — and check what your building’s placement rules say either way.
Frequently asked questions
Can the condensate just drip outside like I see on many buildings?
Common doesn't mean acceptable: water streaking the facade damages the finish over years, and dripping onto windows, balconies or walkways below is exactly what neighbours complain to the manager about. Manager and HOA AC rules typically require routed drainage — and a visible hose dribbling down the wall can put your whole installation in question.
Where is condensate allowed to go?
Typical compliant options: a dedicated drain line to the sewerage (with a trap), to a rainwater downpipe where the building's rules allow it, or to ground/greenery where it harms nothing and no one passes below. Your building manager's AC procedure usually names the accepted options for your house.
What slope does a gravity drain line need?
Continuous fall along the entire run — the rule of thumb installers use is at least 1–2 cm per metre, with no sags or rising sections. If the geometry can't give continuous fall, that's the signal to use a condensate pump instead of hoping.
My indoor unit drips into the room. What went wrong?
Almost always the drain: a sagging or blocked line, a lost slope after furniture moved the hose, or a clogged drain pan. It's the most frequent AC service call and usually cheap to fix — but if the line was laid without proper slope on day one, the fix is relaying it, which is why the detail belongs in the quote.
Does winter heating mode also produce water?
Yes — outdoors. In freezing weather the outdoor unit periodically defrosts, melting ice off its coil; that water drips under the unit and freezes on cold surfaces. Above a walkway or entrance this is a real hazard: use a drip tray or drainage, and never mount directly above where people walk.