I'm going to replace my water heater soon. its a 40 gallon gas, its 30
years old and doing great but getting worried about it because of the
age. its a hotpoint.

I would like to install a whole house water filter on the inlet side
of this new water heater. is this recommended or not for the water
pressure? I've recently upgraded all the appliances to whirlpool but
not sure if whirlpool is good or crap for a water heater.

the house is 2400sq ft L shape with 3 family members 2 full bathrooms
and dishwasher on a slab.