Новая люстра делает комнату светлее и уютнее.

Because новая has to agree with люстра.

• люстра is a feminine singular noun
• the phrase новая люстра is in the nominative singular because it is the subject of the sentence

So the adjective takes the feminine nominative singular ending:

• masculine: новый
• feminine: новая
• neuter: новое

That is why you get новая люстра.

In Russian, nouns have grammatical gender. A noun ending in -а is very often feminine, and люстра follows that pattern.

So Russian treats люстра as feminine, which affects:

• adjective agreement: новая люстра
• verb agreement in the past tense: for example, люстра висела
• pronouns used with it: она

Gender in Russian is mostly a grammatical category, so it is something you usually learn together with the noun.

Because комнату is the direct object of the verb делает.

The sentence structure is:

• Новая люстра = subject
• делает = verb
• комнату = direct object

In Russian, a feminine noun ending in -а changes to -у in the accusative singular:

• nominative: комната
• accusative: комнату

This is one of the most common case changes in Russian.

Here делает means makes in the sense of causes to become.

So:

• делать комнату светлее = to make the room brighter
• делать комнату уютнее = to make the room cozier

Grammatically, делает is:

• 3rd person singular
• present tense
• from the verb делать

Because the subject is singular (люстра), the verb is singular too: делает.

They are comparative forms:

• светлый / светло → светлее = brighter
• уютный / уютно → уютнее = cozier

After a verb like делать meaning make, Russian often uses this comparative form:

• делать что-то лучше = make something better
• делать комнату светлее = make the room brighter

This works very much like English:

• The new chandelier makes the room brighter and cozier.

Because Russian often forms the comparative in one word instead of using a separate word like more.

So instead of something like more bright or more cozy, Russian uses:

• светлее
• уютнее

This is called the simple comparative.

Russian can also use более for comparison, but that usually sounds more formal or bookish here:

• более светлой
• более уютной

In this sentence, светлее и уютнее is the most natural everyday choice.

Because comparative forms like светлее and уютнее are generally invariable in this kind of construction.

Unlike full adjectives, they do not change for:

• gender
• number
• case

So Russian says:

• делает комнату светлее
• делает дом светлее
• делает окна чище

The direct object changes as needed, but the comparative form stays the same.

Yes, the comparison is implicit.

The sentence means that the new chandelier makes the room:

• brighter than before
• cozier than before

Russian often leaves the comparison unstated when it is obvious from context. English does the same:

• This paint makes the room lighter.
• These curtains make it warmer.

If you wanted to say the comparison explicitly in Russian, you could add something like:

• чем раньше = than before

But it is not necessary here.

Because Russian has no articles.

English distinguishes between:

• a new chandelier
• the new chandelier

Russian does not use separate words for that. Instead, definiteness is understood from:

• context
• word order
• the situation being discussed

So Новая люстра could mean:

• a new chandelier
• the new chandelier

depending on the context.

Yes. Russian word order is more flexible than English word order because case endings show grammatical roles.

The sentence as given,

• Новая люстра делает комнату светлее и уютнее.

is a very neutral, natural order:

• subject
• verb
• object
• result

But other orders are possible for emphasis, for example:

• Комнату новая люстра делает светлее и уютнее.

This could emphasize the room.

Even so, the original version is the most straightforward and natural for a basic statement.

Historically and grammatically, it is related to both the adjective idea bright/light and the adverb/state idea brightly/light, and in sentences like this learners usually just treat светлее as the comparative meaning brighter/lighter.

What matters most is how it functions here:

• комната светлее = the room is brighter
• делает комнату светлее = makes the room brighter

The same pattern works with many other words:

• тёплый / тепло → теплее
• чистый / чисто → чище
• тихий / тихо → тише

So for practical learning, it is best to recognize светлее as the comparative form used after verbs like делать and in statements about how something becomes.

уютнее is the comparative of уютный.

It is spelled with -ее, which is a very common comparative ending in Russian:

• уютный → уютнее
• сильный → сильнее
• умный → умнее

For pronunciation, learners often find the sequence of vowels tricky. The important thing is to say it smoothly, roughly as oo-YOOT-nee-ye.

A good strategy is to break it into parts:

• у-ют-не-е

You do not need to pronounce every letter in a heavy separate way, but you should keep the н sound clearly:

• уютнее

It becomes easier with repetition.