En invierno, la estufa del salón nos ayuda a estar más cómodos.

En invierno means in winter.

Spanish often uses en with seasons to mean during that season:

• en invierno = in winter
• en verano = in summer

You may also hear just invierno in some contexts, but en invierno is a very common and natural way to say it.

In this sentence, la estufa means the heater or the stove/heating appliance.

This is worth noticing because English stove usually makes learners think of a kitchen appliance. In Spain, estufa often refers to a heating device used to warm a room. So here it is not a cooking stove; it is something that helps keep the room warm.

Del is the contraction of de + el:

• de = of / from
• el = the
• de el becomes del

So:

• del salón = of the living room / in the living room, depending on context

Here, la estufa del salón means the living-room heater or more literally the heater of the living room.

In Spain, salón usually means living room, lounge, or main sitting room.

So:

• el salón = the living room

It is a very common word in Peninsular Spanish. Depending on the house, people might also say sala de estar, but salón is extremely natural in Spain.

Nos means us.

So nos ayuda means helps us.

The verb is ayudar = to help, and here it is conjugated as:

• ayuda = it helps

The subject is la estufa del salón, which is singular, so the verb is singular too:

• la estufa ... ayuda

Then nos is the indirect/object pronoun telling you who is helped:

• la estufa nos ayuda = the heater helps us

Because ayudar is commonly followed by a + infinitive when you say that something helps someone do something.

Pattern:

• ayudar a + infinitive = to help to do something

Examples:

• me ayuda a estudiar = it helps me study
• nos ayuda a descansar = it helps us rest
• nos ayuda a estar más cómodos = it helps us be more comfortable

So the a is required by this structure.

Because estar is used for states or conditions, and being comfortable is seen as a condition or feeling.

So:

• estar cómodo = to be comfortable
• ser cómodo = to be comfortable in the sense of being convenient or physically comfortable by nature

Here the idea is that in winter, the heater helps us feel / be more comfortable at that moment, so estar is the correct choice.

Cómodos agrees with the implied subject nosotros.

The sentence means that the heater helps us be more comfortable, and us here corresponds to we:

• nosotros → masculine plural or mixed group
• nosotras → feminine plural

So:

• más cómodos = if the group is masculine or mixed
• más cómodas = if the group is all female

Also, más means more, so:

• más cómodos = more comfortable

Spanish often uses más + adjective even when English would simply say comfortable in a natural translation.

Because Spanish usually leaves out subject pronouns when they are not needed.

Instead of saying:

• la estufa del salón nos ayuda a nosotros a estar más cómodos

Spanish normally just says:

• la estufa del salón nos ayuda a estar más cómodos

The pronoun nos already makes it clear that we/us are involved, so nosotros would usually be unnecessary unless you want extra emphasis.

Spanish often uses the definite article (el, la, los, las) where English might use a possessive like my, your, our.

So instead of:

• our living-room heater

Spanish can naturally say:

• la estufa del salón

If the context already makes it obvious whose house or heater it is, Spanish does not need to say nuestra.

You could say:

• la estufa de nuestro salón

but the original sentence sounds more natural and lighter if the ownership is already clear.

Yes, the word order is very natural.

The sentence is structured like this:

• En invierno = time expression
• la estufa del salón = subject
• nos ayuda = verb + object pronoun
• a estar más cómodos = infinitive phrase

Spanish often places time expressions at the beginning, especially to set the scene:

• En invierno, ...

You could also say:

• La estufa del salón nos ayuda a estar más cómodos en invierno.

That is also correct, but the original version emphasizes winter first.

Yes, but the meaning would be narrower.

• estar calientes = to be warm
• estar más cómodos = to be more comfortable

The original sentence is broader. A heater does not just make you warm; it can make the whole environment feel more pleasant and comfortable. So más cómodos is a more natural and flexible choice here.