Зимой старый обогреватель стоит у окна, потому что оттуда тянет холодом.

Зимой is the instrumental singular of зима.

In Russian, names of seasons are very often used in the instrumental case to mean in/during that season:

• зимой = in winter
• весной = in spring
• летом = in summer
• осенью = in autumn

So Зимой here means In winter or During the winter.

You can also say в зиме in some very specific contexts, but not for the normal meaning in winter. For time expressions like this, зимой is the standard form.

Here стоит means stands or more naturally is standing / is placed / is located.

It comes from стоять = to stand.

Russian стоить with an extra -и- means to cost:

• Сколько это стоит? = How much does this cost?

But here the verb is стоять:

• Обогреватель стоит у окна = The heater stands / is by the window

For objects, Russian often uses стоять, лежать, and висеть depending on position:

• стоять = to stand
• лежать = to lie
• висеть = to hang

So a heater can naturally стоять near a window.

After the preposition у, Russian normally uses the genitive case.

So:

• окно = window
• у окна = by the window / near the window

This is why окна is in the genitive singular.

У often means:

• by / near
• sometimes at the home/place of
• sometimes in someone’s possession

Examples:

• у двери = by the door
• у дома = near the house
• у меня есть книга = I have a book

In your sentence, у окна means by the window.

Putting Зимой first sets the time frame right away: In winter...

This is very natural in Russian. The first position often contains known information, background, or what the speaker wants to frame the sentence around.

So:

• Зимой старый обогреватель стоит у окна...
  feels like: As for winter / In winter, the old heater is by the window...

You could move it:

• Старый обогреватель зимой стоит у окна...

That is also grammatical, but the original sounds very natural and smooth.

Потому что means because.

It introduces a subordinate clause:

• ..., потому что оттуда тянет холодом.
• ..., because cold air comes from there / because there is a cold draft from there.

In Russian, a comma is normally placed before потому что when it links two clauses.

So the structure is:

• main clause: Зимой старый обогреватель стоит у окна
• subordinate clause: потому что оттуда тянет холодом

That is why the comma is required.

Because оттуда means from there, while там means simply there.

The sentence is talking about cold coming from the window area, so Russian uses оттуда:

• там = there
• оттуда = from there

Compare:

• Он там. = He is there.
• Он пришёл оттуда. = He came from there.

In your sentence:

• оттуда тянет холодом = cold comes from there / it’s drafty from there

So оттуда is exactly the right choice.

It is partly literal, but in this sentence it is a very natural idiomatic expression.

Тянуть literally means to pull, but in weather/room situations тянет often means:

• there is a draft
• cold air is coming
• you can feel cold air pulling/blowing from somewhere

So:

• оттуда тянет холодом

means something like:

• cold air is coming from there
• there’s a cold draft coming from there
• it feels cold from there

This is a common Russian way to talk about drafts from windows, doors, cracks, etc.

Холодом is the instrumental case of холод.

In expressions like тянуть холодом, the instrumental is used to indicate the thing by which something is characterized or what is perceptible:

• пахнет дымом = it smells of smoke
• веет прохладой = it gives off coolness
• тянет холодом = it draws with cold / there’s a cold draft

So холодом does not mean a direct object here. It is more like:

• with cold
• coldly
• in the form of cold air

This construction is very natural in Russian.

This is an impersonal construction.

Russian often uses verbs in 3rd person singular neuter-like form without a real subject when describing weather, sensations, and environmental effects.

So in:

• оттуда тянет холодом

there is no explicit subject like wind or air. English often needs one, but Russian does not.

It works a bit like:

• Мне холодно. = I am cold.
• Темнеет. = It is getting dark.
• Из окна дует. = It’s blowing from the window.

So тянет here is just the normal impersonal form: there is a draft / cold air is coming.

Yes, very possibly.

For example:

• оттуда дует = it’s blowing from there
• из окна дует = it’s blowing from the window

But тянет холодом has a slightly different feel. It often suggests a draft you can feel, especially indoors, near a window or door. It is very natural for a room with poor insulation.

So:

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

Both can fit similar situations, but тянет холодом sounds especially good for this sentence.

Старый simply means old, but depending on context it can suggest:

• old in age
• old-fashioned
• worn-out
• long-used

In this sentence, старый обогреватель most naturally means an old heater, probably not a new modern one.

It does not automatically mean broken. It just describes the heater as old.

Not exactly.

Обогреватель usually means a heater, especially a device used to heat a room, often portable or electric.

A building’s fixed heating radiator is more often:

• радиатор
• or informally батарея

So:

• обогреватель = heater
• радиатор / батарея = radiator

In your sentence, обогреватель sounds like a heater that has been placed by the window in winter to deal with the draft.

Yes. Russian word order is flexible, though different orders can sound more or less natural depending on emphasis.

The original is neutral and natural:

• Зимой старый обогреватель стоит у окна, потому что оттуда тянет холодом.

Possible variations:

• Старый обогреватель зимой стоит у окна...
• У окна зимой стоит старый обогреватель...

These are grammatical, but they shift focus a little.

The original order is good because it first sets the time (Зимой), then introduces the thing (старый обогреватель), then says where it is (у окна), and finally gives the reason (потому что...). It flows very naturally.