Moves to warm a swimming pool with heat generated by an adjacent crematorium have sparked outrage.
Conservative-run Redditch Borough Council believes it would be an environmentally good use of energy and could save £14,000 a year at the Abbey Stadium pool.
The local authority maintains it would help reduce carbon emissions from energy which would otherwise be exhausted into the atmosphere.
But officials from the union Unison have called the plans "sick and an insult to local residents".
Roger McKenzie, Unison's West Midlands regional secretary, said: "It goes to show yet again that the Conservatives know the price of everything and the value of nothing.
"Unfortunately, local authorities are increasingly pursuing desperate policies in a reaction to the unprecedented spending cuts imposed from Whitehall."
He wants the council to apologise to people in the area for the "insulting and insensitive" proposals.
But the local authority wants to press ahead with consultations over the plan.
A series of briefings will be held later this week, with religious groups, funeral directors and members of the public.

