heat could be warmer!
check out your coolant-- how nasty is it-- could be the heater core is clogged with bar's leak-- could be a "t" stat that is too cold-- many issues.
how hot does your heater hoses get?
an after market gauge will assist, will give you temp of coolant circulating.
start simple, check coolant cleanliness, T stat temp, radiator cap, is collant circulating-- then go from there.
Lawrence