The phrase "a source of warmth" is correct and usable in written English.
It can be used to describe something that provides comfort, affection, or physical heat.
Example: "The fireplace became a source of warmth during the cold winter nights."
Alternatives: "a source of comfort" or "a source of heat".
Such a home can represent a source of warmth and strength.
For now, St. Bonaventure is left without men's basketball, previously a source of warmth here on brutally cold nights.
Rewards also occur outside the laboratory: the mother hen not only scratches up food for her young chicks, she also provides a source of warmth and comfort.
I could feel the people around me leaning in toward the stage, as if it were a source of warmth on a raw, damp day.
They are the bane of women in high heels; a place for flicking cigarette butts, for expectorating chewing gum or for dropping valuables; a source of warmth to ward off a stiff winter's wind; and a frightening opening to detour around.
Sumire was waiting expectantly, snow-white first page of her notebook open, for nourishing words that could have been a source of warmth and comforta pillar, an axis, to help prop up her uncertain life here on this third planet from the sun.
I loved always being a source of instant warmth and comfort for her.
Through his charming, avuncular nature, his wonderful sense of humour, his readiness to poke fun at his own persona, he has become a source of great warmth and delight in many of our lives.
Grappa was the Italian equivalent of Kentucky moonshine: a cheap source of warmth, a lightning path to drunkenness.
The parent-child relationship is a lifelong source of warmth and strength.
If you want your fire to be a continual source of warmth and light, you're going to need to take the next step up.
