Best practice for AC?

[Philliefan33]

Are there any HVAC experts here?

Our vacation home has central AC. I don't know why the original owners built the house with it, but we wouldn't miss it. We've owned the house for almost six years and have run the AC maybe four times.

Last year I ran the AC one night when it was extremely humid. I figured it was a good idea to run the unit at least once a year. If I'm correct, that it is a good idea to run the unit and get things moving, tonight might be the night we run the AC for this year. It's kind of sticky and only cooling down to 69 tonight.

So what would an expert tell me? Is it better to let the unit sit unused for perhaps years on end, or should we crank it up at least once a year?

 

[RobbieB]

All mechanical stuff needs to be run from time to time.

 

[samclem]

I'm not an expert, but I would think running the unit occasionally (probably more than once per year, too), is good for the unit. It likely helps keep the seals in the compressor from "taking a set," it may help keep the thermal expansion valve (TXV) that is on newer units operational, etc. If the refrigerant has an anticorrosion component (I don't now that it does), then circulating it would help put "fresh" anticorrosion chemicals in contact with the pats that need it (this is a good reason to turn on your car's heater a few times in the summer--to run fresh coolant through the heater coil to help it keep from rusting out).

 

[CRLLS]

I agree that running it occasionally is good for the mechanical things. Besides, if you run it when you really don't need it, and you find it needing service, you can have it done before you really do need it. Maybe not necessary for the OP who ran it 4x in 6 years, but more for the rest of us.

 

[Winemaker]

All mechanical stuff needs to be run from time to time.

+10

 

[Walt34]

Agree with the others that in general anything mechanical should be run at least a few times a year. With the older refrigerants like R-22 (not used anymore) the oil in the system and the refrigerant could separate out over time (normally they were mixed well together) and this could cause bad things to happen. It's been 40+ years since I worked on A/C stuff and I forget what the bad things are.

I have no idea if that applies to current refrigerants.

 

[Sunset]

All mechanical stuff needs to be run from time to time.

+++++1

Not an HVAC expert, but lots of experience with stuff.

Might as well run it even when you barely need it, and when it breaks down, decide if you really want to spend the money or not to fix it.

Since you don't need it, when it does become broken, you can just leave it there until you replace the furnace.

 

[Music Lover]

All mechanical stuff needs to be run from time to time.

Yup.

I only need the AC in my car and the house for a couple months in the summer but I don't like letting them sit unused for 10 months at a time, so I always use them a couple times a month from spring through fall.

 

[Koolau]

Agree with the others that in general anything mechanical should be run at least a few times a year. With the older refrigerants like R-22 (not used anymore) the oil in the system and the refrigerant could separate out over time (normally they were mixed well together) and this could cause bad things to happen. It's been 40+ years since I worked on A/C stuff and I forget what the bad things are.

I have no idea if that applies to current refrigerants.

Yeah, back in the day, many car ACs came on whenever you started the car - for a minute or so IIRC. I try to use all ACs at least once a month (car or home.) YMMV

 

[DrRoy]

I have seen that you should run the AC on a car once a month to keep the refrigerant seals lubricated. That may apply to home AC also.

 

[John Galt III]

Interesting. I have a heat pump in my house, which I also use for ac in the summer. This summer, however, I have been toughing it out with just open windows, to save some bucks, and have not had the ac on at all yet! I was wondering about the seals and all that, too. Maybe I'll put the ac on for a few days just during this heat wave in Pa. Win, Win, as they say ! I get cool dry air during the few days of the heat wave AND I save money by making my heat pump last longer.

 

[jimbee]

Many cars also run air conditioning when the windshield defrost mode is on.

 

[Philliefan33]

Thanks all. I'm running the AC today.

 

[Bamaman]

I too am not a HVAC expert, but I do use a lot of it in the Mid South on these very hot Summer days.

If you seldom use the a/c unit, I would suggest you purchase a dehumidifier. You can run an overflow hose into a drain where you don't have to be there to empty the pan. It'll keep the air fresh and keep things from rusting in the house.

I have a 2200 square ft. finished basement with 10' ceilings, 2 bedrooms and 2 bathrooms. Even on these hot days, I just run a dehumidifier and keep my medium sized heat pump shut off. While it's 96 degrees outside, it's still 76 degrees inside and the 50% humidity (treated) is comfortable.

 

[Blue Collar Guy]

Interesting. I have a heat pump in my house, which I also use for ac in the summer. This summer, however, I have been toughing it out with just open windows, to save some bucks, and have not had the ac on at all yet! I was wondering about the seals and all that, too. Maybe I'll put the ac on for a few days just during this heat wave in Pa. Win, Win, as they say ! I get cool dry air during the few days of the heat wave AND I save money by making my heat pump last longer.

I was sweating just reading your post. I run the the A/C a lot. My utility bills reflect this. The heat gets a great work put too. I sometimes have to go outside in the summer, to warm up. I can probably melt the snow on my sidewalk in the winter by just opening my front door..

 

[Nightcap]

Interesting. I have a heat pump in my house, which I also use for ac in the summer. This summer, however, I have been toughing it out with just open windows, to save some bucks, and have not had the ac on at all yet! I was wondering about the seals and all that, too. Maybe I'll put the ac on for a few days just during this heat wave in Pa. Win, Win, as they say ! I get cool dry air during the few days of the heat wave AND I save money by making my heat pump last longer.

Our deck and rear shingling will be replaced this winter, so getting a ductless mini-split installed this summer would have been a waste. But I started keeping a list of all of the nights when I would have slept far better if I had AC. It's now midsummer, and I've stopped making entries. We won't live here for another summer without AC. Call me effete, call me a sybarite, but we're going to be the people who are cool in the summer and warm in the winter and dry in all seasons.

 

[samclem]

Interesting. I have a heat pump in my house, which I also use for ac in the summer. This summer, however, I have been toughing it out with just open windows, to save some bucks, and have not had the ac on at all yet! I was wondering about the seals and all that, too. Maybe I'll put the ac on for a few days just during this heat wave in Pa. Win, Win, as they say ! I get cool dry air during the few days of the heat wave AND I save money by making my heat pump last longer.

If you haven't already done it, it may be worth a couple of minutes to figure out how much running your AC actually costs. We could save money by not running ours, too, but at a 40% duty cycle, our cooling costs us about $4 per day. That's a bargain as far as I'm concerned.

 

[omni550]

I too am not a HVAC expert, but I do use a lot of it in the Mid South on these very hot Summer days.

If you seldom use the a/c unit, I would suggest you purchase a dehumidifier. You can run an overflow hose into a drain where you don't have to be there to empty the pan. It'll keep the air fresh and keep things from rusting in the house.

I'm in Michigan (with hot, humid summers) in an 1850 sq.ft. 2-story house with full basement.

Soon after moving into this house, about 20-25 years ago, I bought a dehumidfier which I used to run in the basement in the summer months. I would notice a large jump in my electric bill (I can't recall how much atm) when running the dehumidifier...but thought I was saving significant $$ over running the whole-house A/C. I'd run window fans on the 2nd floor to cool off the bedrooms at night. Still, there were plenty of days when it was definitely uncomfortably warm/hot inside.

About 10 years ago, I started running the whole-house A/C instead of the humidifer. I was pleasantly surprised when I found that my electric bill went up only about $1/day for the A/C. I got rid of the dehumidifier at that point, switched on the A/C going forward, and never looked back.

YMMV as so much is dependent on your geographic location (and the climate there), size, style, and insulation of your house and windows, efficiency of your A/C, etc.

omni

 

[Bamaman]

I'm in Michigan (with hot, humid summers) in an 1850 sq.ft. 2-story house with full basement.

Soon after moving into this house, about 20-25 years ago, I bought a dehumidfier which I used to run in the basement in the summer months. I would notice a large jump in my electric bill (I can't recall how much atm) when running the dehumidifier...but thought I was saving significant $$ over running the whole-house A/C. I'd run window fans on the 2nd floor to cool off the bedrooms at night. Still, there were plenty of days when it was definitely uncomfortably warm/hot inside.

About 10 years ago, I started running the whole-house A/C instead of the humidifer. I was pleasantly surprised when I found that my electric bill went up only about $1/day for the A/C. I got rid of the dehumidifier at that point, switched on the A/C going forward, and never looked back.

YMMV as so much is dependent on your geographic location (and the climate there), size, style, and insulation of your house and windows, efficiency of your A/C, etc.

You're right that some dehumidifiers can use quite a bit of electricity, however my brand new model is pretty efficient vs. my old unit. And keeping my basement humidity at 50%, I honestly don't hear it running very often.

If I ran my heat pump cooling 2200 square feet of basement all day/night, my total Summer electricity bill would probably increase $150 per month.

 

[Texas Proud]

Not sure about and AC unit...

But, I remember that when I was working that the backup generators were set to run at least a few hours every month.... I have also read that a home unit will also 'exercise' on a regular basis...


Down here there is no way you cannot run it all the time!!!