HP lineset insulation

[ccryan2000]

Just went outside to remove snow from my HP and I noticed that only one line is insulated and when running in HP mode, the warm lineset is exposed to 25 degree air before it goes into the house and I was wondering if this reduces the temperature and efficiency by much. Should both lines be insulated or not? If it is insulated, would that have an impact on cooling?

[geodude]

you should have a small line, (3/8") typical, and a large line (5/8-7/8) typical. The small line is not usally insulated. It wouldn't hurt to insulate it but as a norm they usally are not. If it is a heat pump the small unisulated line should be "luke warm", if it is hot to the touch check your air flow and your air filter. In the heating mode the large line is sending the satuarated or "heated" vapor to the indoor coil to transfer heat to the indoor air. You won't do any harm by insulating the lines more.

[bertqc]

Don't insulate the liquid line...Should not be critical in heating mode but in cooling you want to be sure to have a good subcooling whick will help eliminate flash-gaz which will lead to a better efficiency of your hp in cool.