My home full house airconditioner has been straining to turn on outside. It appears to be struggling and starts slower. After returning home from summer vacation we turned the unit on and the furnace plugged up with ice within an hour. Repairman told me that this happened because of a low freon situation. He put 4 lbs into the unit outdoors. Any expert info would be appreciated. We live in Michigan and the weather at the time of the ice block was in the high 1990s with very high humidity.

Yes, low freon will cause freeze up. So will lack of airflow at inside evap coil. Did he find a leak? If the unit needs charging again, its time to start looking for the source of the leak.

As for the unit struggling to start up. Sounds like you may need a hard start kit (capacitor) to help the compressor start up.

I will agree, freezing up is a good sign of low freon. Did he find any leaks ? How long since you had it serviced and filled with freon

My unit is approximately 15 yrs old. No evidence of any leaks were detected. The furnace filter is changed frequently. The build up of ice ontop of the furnace only happens after a duration or downtime of 3-4 weeks, when I return home it is usually very hot and humid in the house. The air conditioner runs for several hours, working well, blowing very cold air. Then the furnace starts sweating and leaking down the furnace as the cold air turns warmer. One year I had to turn the furnace on just to melt the glacier that formed. The pump evacuated water like a garden hose, for an hour. Then after starting all over again the system worked great the rest of the hot summer, with no lagging upon start. Since the freon was put in it didn't seem any colder, just the straining to start. I did notice that the outside condenser fan turns on before the pump is up and running. That never happen before (that I recall). This is the first time that freon had to be added, but, the ice build up has been happening for the last 5-years. This year I decided to lower the temp from 95 (inside temp) to 76 in steps, to avoid too much to fast. Seemed not to ice up at all. Not to mention my electric bill (normal) went from $160. To $255.00 last month. The lights (all lights) draw down considerably when the air turn on and surges. Worse than my large 220 Air Compressor when it turns on. I know absolutely nothing about electricity, other than it's a lot faster than I. Would it be worth it to have another professional check the freon? Would too much freon cause a problem in the pump? Sorry for the enormous answer. (My unit is a Comfort Maker. 2 ton unit.) Thanks for your responses.

Hi wy. Yes indeed, an extreme overcharge will cause hard starting of the compressor. You say he added four pounds, and you have a two ton unit? Sounds like either you were almost completely out of refrigerant, or the system is now extremely overcharged. May want to have another tech out to check things out, or if the unit is 15 years old, just wait till it dies completely (compressor failure), and update the system to a R410a system. The newer units are more efficient, but a bit spendy in purchase and install. Your call. Good luck, take care.

Thanks all for the information. I will have another person check it over. I would love to get as much out of this unit before having to go broke with the newer version. Although it will save on the electricity. Thanks.