"Bob" wrote in message
...
My house, built in 1956, needs a new heating system boiler. It's as old as
the house.

I've seen some models that have domestic hot water (DHW) capability - are
these worth getting? It seems to be a waste to turn on a boiler rated
50,000-250,000 BTU for hot water in the dishwasher.

A waste compared to what? How is you current DHW being produced? During cold
weather a domestic coil is probably more efficient than a separate DHW
system