Hello from B.C. Canada... westcoast... expecting Severe winter here?? My modular home 1 yr... to insulate my water pipes... approx cost to do so.. my square footage is 420SF.. appreciate knowing.thankx.tuliphour

Do your pipes pass through unheated spaces? The builder knew your climate and it should be built to code for your area. What makes you think you will have a problem?

Without knowing the condition of and access to the pipes its hard to estimate the cost. You might want to consider installing a Redytemp to do the job. It will intermittently circulate warm water throughout both your cold and hot water lines, preventing freezing from the inside of the pipes. It uses a lot less energy then heat tape, there's no maintenance and you'll have the convenience of not having to wait for hot water anymore.

It's almost impossible to estimate a job without being on site to make a material list and see any future problems that might come up. Get three estimates and go with the one you're most comfortable with. Good luck, Tom

Waiting to hear more from the OP. A new home built is a cold climate should be able to operate without further insulation, if built to code