kono heya ha hiatari ga ii kara, asa ha denki wo tukenakute mo akarui desu.

日当たり means exposure to sunlight or how much sunlight a place gets.
So 日当たりがいい means gets good sunlight or is sunny.

In this sentence, この部屋は日当たりがいい means:

• This room gets good sunlight
• or more naturally, This room is sunny

The reading is ひあたり.

This is a very common pattern in Japanese.

• この部屋は sets the overall topic: as for this room...
• 日当たりがいい says what quality the room has: its sunlight exposure is good

So the structure is roughly:

• この部屋は = As for this room
• 日当たりがいい = the sunlight exposure is good

Japanese often uses は for the main topic and が for the specific thing being described within that topic.

Both いい and よい mean good.

• よい is the dictionary/base form
• いい is the very common everyday form

So 日当たりがいい is the normal natural way to say it in conversation.

One thing to notice: in some conjugations, よい shows up again. For example:

• よくない = not good
• よかった = was good

So even though the plain positive form is often いい, other forms often come from よい.

から means because here.

So:

• 日当たりがいいから = because it gets good sunlight

The sentence is giving a reason:

• Because this room gets good sunlight, it is bright in the morning even without turning on the lights.

This から connects the cause and the result.

朝は marks morning as the topic or time frame: as for the morning / in the morning.

Here, は adds a slight sense of contrast or focus:

• At least in the morning, it’s bright...
• or simply In the morning, ...

You could think of 朝は as setting the scene:

• As for the morning, this room is bright even without turning on the lights.

Using に would focus more on a specific point in time, but 朝は sounds more natural here because the speaker is talking about mornings in general.

Literally, 電気 is electricity and つける is to turn on / switch on.

But in everyday Japanese, 電気をつける usually means:

• to turn on the light
• to switch on the lights

So even though the word is literally electricity, the natural English meaning here is turn on the lights.

つけなくても comes from the verb つける (to turn on).

Breakdown:

• つける = to turn on
• つけない = do not turn on
• つけなくて = not turning on
• つけなくても = even if you do not turn it on / without turning it on

In this sentence, 電気をつけなくても means:

• even if you don’t turn on the lights
• without turning on the lights

This pattern なくても is very common and often means even without doing X or you don’t have to do X for Y to be true.

The も adds the sense of even.

So:

• つけなくて by itself is just not turning it on
• つけなくても becomes even if you don’t turn it on / without turning it on

That is why the sentence has the nuance:

• It’s bright even without turning on the lights.

This will probably catch a learner’s eye: the standard modern spelling is 明るい.

So most learners would expect:

• 朝は電気をつけなくても明るいです。

明い is not the normal standard form in modern everyday Japanese. In learning materials, this is very likely:

• a typo, or
• a nonstandard/old-style variant

So if you are learning standard Japanese, you should use 明るい.

Japanese often leaves out things that are clear from context.

After この部屋は日当たりがいいから, it is already understood that the sentence is still talking about this room.

So 朝は電気をつけなくても明るいです naturally means:

• As for the morning, it is bright even without turning on the lights
• where it = this room

Japanese avoids repeating nouns when they are already understood.

No. Normal Japanese is usually written without spaces between words.

So this sentence would normally appear as:

この部屋は日当たりがいいから、朝は電気をつけなくても明るいです。

The spaces in your version are just there to help learners see the different parts more easily.

Yes, it could.

• から = because
• ので = because / since

Both work, but ので often sounds a little softer or more explanatory.

So this version would also be natural:

この部屋は日当たりがいいので、朝は電気をつけなくても明るいです。

The original with から is perfectly natural and common.

A useful way to break it down is:

• この部屋は = as for this room
• 日当たりがいいから = because it gets good sunlight
• 朝は = in the morning
• 電気をつけなくても = even without turning on the lights
• 明るいです = it is bright

So the whole logic is:

As for this room, because it gets good sunlight, it is bright in the morning even without turning on the lights.