Learn Hardcore Portuguese (Portugal): Se fizer frio, queimamos lenha na lareira para aquecer a casa. - If it is cold, we burn firewood in the fireplace to heat the house.

Fizer is the future subjunctive of fazer. In Portuguese, when you introduce a condition with se referring to something that may happen in the future, you use the future subjunctive. Here, Se fizer frio literally means “If it gets cold.” You form it by taking the third‑person plural of the preterite (fizeram), dropping ‑am (→ fizer).

Could we say Se faz frio or Se está frio instead of Se fizer frio?

Both Se faz frio and Se está frio are grammatically correct but carry different nuances:

Se faz frio uses the present indicative of fazer for a general or habitual condition: “If it’s cold (whenever that happens)…”
Se está frio (present indicative of estar) talks about a current state: “If it’s cold (right now)…”
Se fizer frio (future subjunctive) points to a possible future event: “If it gets cold (later)…”

What does queimamos mean? Could it be past tense?

In this sentence, queimamos is the first‑person plural present indicative of queimar: “we burn” or “we use.” Although in Brazilian Portuguese the past tense (pretérito perfeito) of nós is also spelled queimamos, in European Portuguese the past form is spelled queimámos (with an acute accent). Here there’s no accent, so it must be present: “we burn firewood to heat the house.”

Why is the word lenha used instead of madeira?

Lenha specifically means “firewood,” i.e. wood cut and seasoned for burning. Madeira is “wood” in general (timber, lumber). Since you want wood that you can burn in the fireplace, lenha is the correct term.

What is a lareira, and is there another word for it?

A lareira is a “fireplace,” the built‑in hearth or structure where you make a fire indoors. You might also hear fogão a lenha for a wood‑burning stove, but lareira is the standard term for an open indoor hearth.

What is the function of para + infinitive in para aquecer a casa?

Para + infinitive expresses purpose or in order to. So para aquecer a casa means “in order to heat the house.”

Why is the article a used before casa but not before lenha?

A casa is a definite noun (“the house”), so it takes the article a. Lenha, however, is mentioned in an indefinite or uncountable sense (“(some) firewood”), so no article is required.

Is the comma after Se fizer frio necessary?

Putting a comma after an initial subordinate clause (like Se fizer frio) is recommended in Portuguese to separate it from the main clause. It isn’t strictly mandatory—especially if the clause is very short—but it greatly improves clarity.