I can't find anything locally short of buying an entire                carton - we only need approx 12'. Amazon has this - but                I'm not sure if ⅜" thickness is enough.  And/or, we had                planned to wrap it with the heat tape like the pipes in                the barn are, but again — how much is enough - too much?                 If we have to give $100+ for a box of insulation, we                might as well hire a plumber to do it.  Open to any                suggestions.  Christmas day is supposed to be 65, and                raining — go figure, only in MO.  But it will turn cold                again and we want to be prepared.
              
              
              Thanks guys.  DH not up to planning this and                I'm flying blind.  We can pull off the siding, reach in                and wrap the pipes, then wrap with the heat tape and plug                it in under the sink.  At least that seems to be                reasonable.
                                                                                          
2-1/8" x                          6 ft. Polyethylene Pipe Insulation, 3/8" Wall
                                                                                                                                                      
                                                                                                                                          | Price: | $7.07 & FREE                                      Shipping | 
                                              
                                                                              Note: Not                      eligible for Amazon Prime.
                                                                                                                                           Get it as soon as Dec. 30 - Jan. 5 when                          you choose Standard at                          checkout.
                                                                                                                       Eligible for 

 donation.
                                                                                     - Price For: Each Insulation Type:                            Pre-Slit Item: Pipe Insulation Length: 6 ft.                            Material: Polyethylene Green Certification or                            Other Recognition: GREENGUARD Certified Green                            Environmental Attribute: Product Contributes                            to Reducing Energy Consumption Color: Black                            Standards: ASTM C 1427 Temp. Range: -160                            Degrees to 200 Degrees F Wall Thickness: 3/8"                            Approx. R Value: 1.7
- Country of Origin (subject to change):                            United States