Even down here in the Arizona desert they ice up pretty quickly. My guy said a heat strip takes care of that but I won't like the electric bill that comes with it. Heat pumps are pretty good air conditioners but not so much a heater in my opinion.

You sir are the only person that addressed the question on the ice build up across multiple forums including those on HVAC

When my brothers new unit was icing up it took several service calls to find out there was a loose wire in the unit. There's a difference between icing up and defrosting. Defrosting keeps it from icing up. If a unit is icing up somethings wrong or it's not rated for the cold temp it's trying to be run in.

Do you happen to know what the outside temps were? we were well into the minuses been 40's and high 50's lately. they are supposed to be out Tuesday Kinda feel a bit back burnered but it is a warranty job (pays less) and I do have heat so

Perhaps the HVAC industry should offer a $100,000 prize to an inventor to somehow reduce the defrost problem?

Summer time fins cleaning is also important.

My well intentioned sister replanted my mother’s garden and it looked great.

Then she hired a crew to mulch it.

This non-english speaking crew was throwing fine wispy black mulch with shovels, and decided to also “carpet bomb” the ground around the air conditioner by throwing in that general direction while the unit was drawing in air.

Any time we go below freezing(not very often) and we have a little humidity my 5 ton rooftop Trane will reverse to defrost almost as much as it heats so it will run pretty much all night until the sun hits it. Done it since new and had it checked by several techs. I keep the stat set at 69 degrees.

When the wire was loose it would have icing problems on and off even in mild weather as high as 40. No problems since problem was found.