What is the difference between a furnace and a boiler?

Hi everyone,

On Monday night, at Roundtable in Ermont, we were speaking about the weather.
I must say that a member of ours worked at Météo France and weather is a common subject... never opened by him (he's a bit fed up with questions or complaints) LOL)

We were looking for a word in English for the device that heats a house.
A member said "boiler". I said "furnace".

I knew about "boiler" but I remembered an American friend who was saying "furnace".

When I have a look into my HO (Hachette-Oxford) dictionary: from the French side, they say "boiler"; from the English side, "boiler" is the general term, "furnace" is something huge (industrial) but I hardly trust this dictionary which is a bit too British so I sometimes go on with the Inernet looking for the words by Merriam-Webster or Urban.

What do you think?
What is the difference between a furnace and a boiler?
Is the Hachette-Oxford Dictionary totally right?

Hi Gérard
See what I have found

Many homeowners may confuse these terms, but, there is an easy way to remember: a boiler uses hot water (think of "boiling" water) to heat your home, and a furnace uses warm air (also referred to as forced air).

Hi Muriel,

Thanks for your words!
An EMT told me furnace was American and boiler was British but I suspected her to simply wish to please myself

Then I found the words you posted.

So, both furnace and boiler can be used depending on the technique water or air.