O medidor de energia fica fora da casa.

It means energy meter, and in everyday context it usually refers to the electric meter for the house.

In Brazil, people might also say:

• medidor de luz
• relógio de luz (very common in casual speech)

So O medidor de energia fica fora da casa is talking about where the meter is located.

O means the, while um means a/an.

So:

• O medidor = the meter
• Um medidor = a meter

Here, o is used because it refers to a specific meter, probably the one belonging to that house.

Yes, ficar often means to stay, but it also commonly means to be located.

In this sentence:

• fica fora da casa = is located outside the house

This is very natural Portuguese. Some examples:

• O banheiro fica no fim do corredor. = The bathroom is at the end of the hallway.
• A padaria fica perto daqui. = The bakery is near here.

So here fica is about location, not about “staying” in the sense of remaining somewhere temporarily.

Because Portuguese often uses ficar to talk about where something is situated.

Compare:

• A escola fica perto da praça. = The school is near the square.
• A escola é grande. = The school is big.

So:

• é describes an identity or characteristic
• fica often describes location

Using é fora da casa would sound wrong here.

Both exist, but they mean different things.

fora da casa

This means outside the house — physically on the exterior of that specific house.

fora de casa

This usually means away from home / out of the house, often in a more general sense.

So in this sentence, fora da casa is correct because we are talking about the meter’s physical location relative to the house.

Da is a contraction of:

• de + a = da

So:

• fora da casa literally = outside of the house

This kind of contraction is very common in Portuguese:

• de + o = do
• de + a = da
• em + o = no
• em + a = na

Portuguese uses definite articles very often, more often than English in many situations.

Here, da casa refers to a specific house, so the article a is used and contracts with de:

• de + a casa → da casa

This is very natural Portuguese.

It is understandable and correct, but many Brazilians would more naturally say:

• O medidor de energia fica do lado de fora da casa.

That sounds a little more explicit and idiomatic.

Still, fica fora da casa is perfectly clear and acceptable.

You could, but it changes the feel a bit.

• fica fora da casa = it is located outside the house / that’s where it is
• está fora da casa = it is outside the house (more temporary-sounding in some contexts)

For permanent or usual location, fica often sounds more natural.

Both are possible, but energia is very common in Brazil when talking about household electrical service.

So:

• medidor de energia = very natural
• medidor de eletricidade = understandable, but less common in everyday speech

In daily Brazilian Portuguese, people often shorten this kind of thing.

Yes, if the context is clear.

For example, if you are already talking about the house’s utilities, a Brazilian might simply say:

• O medidor fica fora da casa.

But if you want to be specific, o medidor de energia is clearer.

The structure is:

• O medidor de energia = subject
• fica = verb
• fora da casa = location phrase

So literally:

• The energy meter is-located outside the house.

This is normal Portuguese word order and matches English fairly closely.

Some very natural alternatives are:

• O medidor de energia fica do lado de fora da casa.
• O relógio de luz fica do lado de fora da casa.
• O medidor fica fora da casa.

The best choice depends on how formal or casual you want to sound. Relógio de luz is especially common in everyday speech in many parts of Brazil.