# Why caulking/sealing holes is a top-tier hack:

1. Heat loss prevention - Small gaps around pipes, outlets, baseboards, and wall penetrations can account for 10–20% of heat loss in a home. Sealing them is cheap and has immediate impact on heating efficiency.

2. Noise reduction - Sound travels through gaps, especially in shared walls or floors. Sealing holes between units drastically cuts down on neighbor noise. Noise can travel up a pipe if there is air around it. This can reduce massive amounts of nighbour noise. 

4. Odor control - Cooking smells, smoke, or bathroom odors from adjacent units can seep through pipe penetrations. Fireproof caulk blocks these pathways.

5. Pest prevention - Silverfish, roaches, spiders, insects, mice, and even small rats can squeeze through surprisingly tiny gaps. Sealing entry points is one of the most effective (and non-toxic) pest control methods.

6. Fire safety - Fireproof caulk or foam helps slow the spread of fire between units by sealing penetrations in fire-rated walls.
   
8. Dangerous gases - Any gas from another unit/house cannot enter, which might save your life. Some gases cannot be smelled.
   
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### Caution

> Always use fireproof caulking agents or foams. If in doubt, use cement-type caulks. (harder to remove though)

> Be extra careful around central heaters. Only use a special caulk for this, because not every caulk can be used, even if it is fireproof! If in doubt, use glasswool instead.

### Where to caulk/seal:
- Around pipes entering/exiting walls (especially under sinks, behind radiators, or where plumbing passes between units)
- Electrical outlets and switch plates on exterior walls
- Gaps around baseboards, door frames, window frames
- Cracks where walls meet ceilings or floors
- Vent and exhaust fan openings
- Cable/internet entry points

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### Materials to use:
- Fireproof/intumescent caulk or foam for pipe penetrations in shared walls (expands and hardens in heat to block fire spread)
- Silicone caulk for kitchens/bathrooms (water-resistant)
- Acrylic/latex caulk for interior gaps (paintable, easy to work with)
- Weatherstripping for doors and windows

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### Impact:
This is a high-impact, low-cost upgrade. For the price of a few tubes of caulk (~€10–20) and an hour of work, you get:
- Lower heating bills
- Better comfort (less drafts, noise, smells)
- Fewer pests
- Improved safety

It's one of those rare hacks that solves multiple problems at once with minimal effort.