От окна тянет холодом, поэтому я закрою окно.

Because от is the natural preposition here for the source of a draft, cold, smell, or some physical sensation coming from the direction of something.

• от окна тянет = there’s a draft coming from the window / from the area of the window
• из окна more literally means out of the window or from inside the window opening

So in this sentence, от окна does not mean something is coming from inside the window; it means the cold is coming from that side / from near the window.

Also, от requires the genitive case, which is why окно becomes окна.

Yes, the basic meaning of тянуть is to pull, but in this sentence it is used in a very common impersonal way.

Here, тянет means something like:

• there is a draft
• cold air is coming
• it’s blowing cold

So От окна тянет холодом means roughly:

• A cold draft is coming from the window
• It’s blowing cold from the window

This is one of those cases where Russian uses a verb more broadly than English does. You can think of it as an idiomatic weather/sensation expression.

This is an impersonal sentence. Russian often uses verbs without an explicit subject when talking about:

• weather
• physical sensations
• smells
• drafts
• general states

So тянет here does not have a stated subject like ветер or воздух.

It works like:

• Пахнет дымом. = It smells like smoke.
• Дует из окна. = There’s a breeze coming from the window.
• Тянет холодом. = It’s blowing cold / there’s a cold draft.

The verb stays in 3rd person singular form by default in this kind of construction.

Because after verbs like тянуть, пахнуть, веять, Russian often uses the instrumental case to show what kind of sensation, smell, or quality is coming from something.

So:

• холод = nominative
• холодом = instrumental

In this sentence:

• тянет холодом = it blows with cold / there’s a cold draft

Compare:

• Пахнет дымом. = It smells of smoke.
• Веет прохладой. = It gives off coolness.
• От двери тянет сыростью. = There’s a damp draft coming from the door.

So холодом is not random—it is the normal case in this pattern.

Yes, you can say поэтому я его закрою, but repeating окно is often perfectly natural in Russian.

So both are possible:

• От окна тянет холодом, поэтому я закрою окно.
• От окна тянет холодом, поэтому я его закрою.

Why repeat the noun?

1. Russian often repeats nouns more freely than English does.
2. It can sound clearer and less ambiguous.
3. In a short sentence like this, repetition does not sound awkward.

English prefers pronouns more strongly, but Russian is often comfortable repeating the noun.

Because закрою is the perfective future of закрыть, and it means a single completed action:

• I will close the window

That fits the situation well: the speaker decides to do one concrete thing.

Aspect here

• закрывать = imperfective
• закрыть = perfective

Future forms

• буду закрывать = imperfective future, meaning something like I will be closing / I will close repeatedly / in process
• закрою = perfective future, meaning I will close it (and the action will be completed)

So поэтому я закрою окно is the natural choice.

Because they are in different cases.

After от

The preposition от requires the genitive case:

• от окна = from the window

After закрою

The word окно is the direct object, so it goes in the accusative case:

• закрою окно = I will close the window

For an inanimate neuter noun like окно, the accusative singular looks the same as the nominative singular:

• nominative: окно
• accusative: окно
• genitive: окна

So the difference is grammatical, even if one form looks unchanged.

Поэтому means therefore, that’s why, or so.

In this sentence, it connects two clauses:

1. От окна тянет холодом
2. поэтому я закрою окно

The comma is there because these are two separate clauses, and поэтому introduces the result of the first one.

So the logic is:

• Cold is coming from the window, therefore I’ll close the window.

This punctuation is normal.

Yes. Russian word order is flexible, although some versions sound more neutral than others.

The given sentence is very natural and neutral:

• От окна тянет холодом, поэтому я закрою окно.

Possible variations:

• Холодом тянет от окна, поэтому я закрою окно.
• Поэтому я закрою окно: от окна тянет холодом.
• Я закрою окно, потому что от окна тянет холодом.

Changing the word order changes the focus or style, not the basic meaning.

The original version is a very good standard way to say it.

You might hear similar expressions with дуть, but тянуть холодом is a very common and idiomatic way to describe a cold draft.

Compare:

• От окна тянет холодом. = very natural for there’s a cold draft from the window
• Из окна дует. = it’s blowing from the window
• От окна дует холодом. = understandable, but the phrasing with тянет is especially common in this type of situation

So your version may be understood, but the original sentence sounds very natural and idiomatic.

People really say this. It sounds natural in everyday speech.

It is:

• not especially formal
• not slangy
• very normal conversational Russian

A native speaker might use it when sitting near a badly sealed window in winter.

So this is a useful real-life pattern:

• От двери тянет.
• От окна тянет холодом.
• От балкона тянет.

These are all practical everyday expressions.

Grammatically, that reflects the Russian words a bit, but it is not natural English.

A better English translation would be:

• There’s a cold draft coming from the window.
• It’s blowing cold from the window.
• Cold air is coming from the window.

So this is a good example where a literal word-for-word translation is less helpful than learning the whole Russian pattern as an expression:

• От X тянет Y-ом = There’s a Y draft/sensation coming from X