Lg 8000 a/c

techntrek

As mentioned on the Feders thread, I recently bought a LG 8000 BTU window shaker. Finally hooked it up to my Kill-A-Watt this evening. Outside temps around 80-82 F, inside temp set to 71 but my wall thermometer says 74. Room size is about 450 sq. ft.

Running wattage is almost 700 with the compressor running and fan on low; PF is .95. When the compressor is off, fan on low, it uses about 100 watts and the PF drops a little to .92. Average useage per hour over the last 6 hours has been 525 watts.

This unit has an Energy Saver mode which will cycle the fan with the compressor. I'll try that tomorrow evening and post back with the numbers. The outside temps will be about the same so it will be a good comparison. Looking at the numbers above it may shave off 1/5.

waynefromnscanada

Re: Lg 8000 a/c

Well one thing I'm learning after having personal experience with both, is how efficient Mini Splits are compared to "window shakers". Seriously had no idea the mini splits could be that much more efficient - - AND QUIET! They sip at the power supply, while window shakers gulp it like starving pigs. On the other hand, window shakers are cheap to purchase and easy to install.

techntrek

Re: Lg 8000 a/c

That's the only reason I have one right now - cost and installation. A stop-gap until I get a mini-split in that one room. While not as efficient as the mini-splits, it is still cheaper to run than the whole-house unit that fed my entire downstairs (now broken), which I've discovered was extremely over-sized for the job. Even in the recent heat wave, and even waiting until that room gets too warm mid-day before firing it up, the air flowing down the stairs from the upstairs whole-house unit plus that one window unit keeps the entire downstairs comfortable.

Basically 24,000 BTUs (2 tons) has been replaced with 8,000 BTUs with little noticeable difference. Good to know since I wasn't sure if I should go with the 9,000 or 12,000 BTU Mitsubishi... then again my heat load in the winter at temps near the low-end operating range is a bigger issue so the 12k may still be the answer. I'll get my electric bill in the next day or two so I can see if there is any overall kw savings from the change. Most of this heat wave occured after the meter reading date so that shouldn't affect a year-to-year comparison much.

Ralph Day

Re: Lg 8000 a/c

I think you'll be pleased with the 12000btu Mitsubishi unit. Mine's not running today, it's cooled off considerably.

The old central air system in this house sat unused during my off-grid stint (6yrs), and was seldom used before that (too cheap!) It was 1.5ton I think. That was too big for the house with the result that it didn't run long enough to dehumidify sufficiently...hence the house was cool and uncomfortably clammy, not cool and dry (plus we wouldn't run until the house was hot and humid inside).

Ralph

techntrek

Re: Lg 8000 a/c

I just passed the 3 hour mark using the Energy Saver setting. Operating parameters are nearly the same, a degree lower outside. Looks like I was wrong, a drop of 1/5 was incorrect.

Instead, its a 2/5 drop. It is averaging 320 watt-hr, far below what I expected. That is maybe 50 watts more than a 9k Mitsubishi on low, I believe?

The only difference is the room feels slightly warmer, my wall thermometer reads 75 instead of 74. Ironically I'll need to wait for another heat wave so I can see what this uses when it is 95 outside and not 80.

techntrek

Re: Lg 8000 a/c

Found something very interesting, I've been watching the Kill-a-Watt's display as it starts up the compressor when it is in Energy Saver mode, and it appears to be doing a partial soft start. The first wattage measurement is in the mid-400s, around 450, when the compressor first kicks on. Then over about 10-15 seconds it slowly ramps up to its max wattage in the mid-600's to just below 700.

TheBackRoads

Re: Lg 8000 a/c

My portable a/c does this, I thought it may take a bit for the refrigerant to build pressure therefore increasing wattage slowly? I'm just guessing however....

LucMan

Re: Lg 8000 a/c

Great guess! But that is the reason.

techntrek

Re: Lg 8000 a/c

But I don't remember seeing this ramp-up when its in the normal cooling mode. I'll have to check again next time its warm enough to turn it on.

techntrek

Re: Lg 8000 a/c

I forgot to check out the normal cooling mode, but its hot again and I have more data. Yesterday I measured it over 6 hours, outside temp started out at 92 and slowly fell. I forget the bottom temp but most of the time was in the upper 80's. Highest running wattage I saw was nearly 750 watts. Average watt-hr over the 6 hours was 456 watts.