  We obtain (i) lower and upper bounds for the heat content of an open set in
$\mathbb{R}^m$ with $R$-smooth boundary and finite Lebesgue measure, (ii) a
necessary and sufficient geometric condition for finiteness of the heat content
in $\mathbb{R}^m$, and corresponding lower and upper bounds, (iii) lower and
upper bounds for the heat loss of an open set in $\mathbb{R}^m$ with finite
Lebesgue measure.
