Higher efficiency window unit?
 

I am looking for a big 18,000btu 220v powered window unit that has a SEER rating greater than 12.
Are there any window units out there higher than 12?

I'm finding big window A/C units that have dreadfully low SEER ratings of like 9, 10 and barely over 11.

Even the cheapest non inverter split unit I can find has a SEER of around 15.

I may have to do a creative through the garage split install with condensation pump if I can't find a decent window unit.

Window units are not rated in SEER. They are rated in EER.

Central air conditioners are rated in both. There is a difference.

EER is a rating determined by a single standard condition, which SEER ratings are determined with multiple conditions, including conditions where it is cooler and the units operate more efficiently.

As a very rough figure, 13 SEER is roughly 11.5(+/- 5 depending on the system) EER in the standard split-system central air setups.
Usually the window AC units that are energy star that you can find on Craigslist are around 10.7 EER, this is around the 12-12.5 SEER range. The Energy Star standards changed about 2 or 3 years ago, but before that, the standards on the smaller units was around 10.7 EER.

Compared to the window air conditioners from the 70's and 80's that most older apartments still have installed today, the new energy star units are a significant improvement.

I think that the newest units out today that are roughly a 13 SEER or close to it are pretty good for a unit the size of a large luggage carry-on. These things have small coils in relation to their output and have their outlets in close proximity to their inlets.

I was actually disappointed when I saw non-inverter mini-splits with only 13 SEER, it seems with a ductless system that 15+ SEER should be close to automatic with large coils and no ductwork.

So it's still low efficiency compared to a good split inverter unit.

For a rough estimation, add 3 to the EER rating to get the SEER rating for window units. EER is measured at static conditions (95 degF outdoor / 75 degF indoor or close to it) and is directly equivalent to COP. SEER is not directly related to COP at many moments in time, it's just an average value that is calculated to yield higher numbers out of units that don't perform as well when it gets above 95 degF outside.

The industry does this to confuse the general population. For example, a 9000 btu window unit will generally have an EER that is 3 less than the SEER of a mini-split that has the same performance. Believe it or not, that 3 points sells lots of people into a mini-split that costs twice or three times as much. To be fair, there are more aspects to consider than raw performance. Apples versus oranges and such.

Window units without capacity control aren't going to have heavenly efficiency numbers. Manufacturers aren't highly interested in cramming inverter compressors and electronic expansion valves into window units. They are more interested in reducing the size and weight of window units to reduce handling difficulty and raw production cost. The energy star standard of 10.2 to 11 (depending on capacity) is good enough for 99 percent of everyone, so the cheaper and quieter and lighter that units can be designed, the more they will be competitive in this low-cost sector. In other words, they are not cost effective to improve much.

A new number, CEER, is the new EER for digital control board having room a/c units. It includes the standby power loss (5115 hrs x 1.4W vs. 750 hrs active load W) in the rating. I don't imagine it would be significantly different from EER, but it is a new number to further confuse the innocent.

Yes that's what it looks like, with the window units it's like who can make the cheapest one in compliance with government energy standards.

Wife doesn't mind spending the $ on a 2 ton inverter split.
We're looking at ones on ebay with 20 and 21 SEER rating. Since it will be quieter and use less energy than a window unit.
20 to 21 SEER seems to be the normal rating for the larger 2 ton and up inverter units.

I have never heard of or seen a window unit that does something more advanced than just turn on and off.

A 2 ton window unit at home Depot has a CEER of 9.8, that seems kind of low.

Packing 24000 BTUhr of capacity into a window unit is asking for a pile of heat exchange to occur in a very small package with small condensing and evaporator coils. I really don't see needing that kind of capacity at a single point source unless that is in an area with a significant amount of glass, cooking loads, or some other high load environment. I think most people who probably buy one of these huge window units either thought 'bigger is better', or 'hey, this fits the measurement of the window, I don't need to build or buy a spacer'. There are some niche applications for a single point air conditioner of a 2 ton capacity but I don't think many people buying these are buying the proper size.

My 2100sq ft house should have a 1.5 ton central air system, but has a 2 ton 8.5 SEER(yes, SEER) system built in 1986. If I didn't have roommates living in the house, I'd toss my 5350BTUhr(500 watt 10.7 EER) unit back into the bedroom window and keep the bedroom door shut and call it good. I don't mind using my bedroom as a living space when I'm the only one here, saves a pile of money. The air conditioner was either $20 or $40 on Craigslist, was an EER rating that was still Energy Star compliant at the time I bought it, and cools the bedroom with the door shut just fine. I've never actually seen it use 500 watts, it's usually under 450 watts and the capacity at lower than the 95 degree test conditions is probably higher. I'm getting a rough SEER of probably 12-12.5. At 450 watts and a worst case day where it runs for 18 hours, it's consuming about 8kwh. My central air burns that much power in about 3.4 hours and if I'm cooling the whole house, it will use way more than that on even an 80 degree sunny day.

For the price I bought it for and my niche single room use for air conditioning, a mini-split wouldn't pay off. If I open the bedroom door and let it cool the rest of the house off and use the existing 2 ton for a few hours to supplement on the hottest days, a 1 ton mini-split would be great and if I use it for heating with the door shut method, keeping the rest of the house cooler, it would save quite a bit on heating in the shoulder months. The natural gas in my area is dirt cheap (65 cents per therm) and electric heat is currently 4.5 times the cost. Getting a COP of 4.5 at temperatures that I actually need heat in Minnesota is not easy, even with a mini-split, so heating a smaller space while letting the rest of the space be colder would be the only real way to be cost positive.

Down from 10 EER on account of the digital control. Twisty knobs don't add any vampire load.

What is the intended purpose of the unit? Temporary, permanent, seasonal, year-round? What area will it serve? Why a window unit? It sounds like you're steering towards a mini-split or split system, so the cost and scope increases in that general direction. Better research is justified in this case.

If I installed a heat pump inverter split like I did in the bedroom I would use it year round.

The window unit is just a quick and dirty way to cool off the house.

I bought the 2 ton senville inverter split, 20 SEER.
No window unit.

did you get this model: SENA/24HF/Z ?

I'm curious about these units now. The Senville website has none of the usual charts and/or spreadsheets that depict performance. Without comprehensive performance data, how would a competent engineer, architect, or HVAC tech size the unit to the space and heat load? They wouldn't.

Looking straight at their website, the model cited quotes only 3 performance figures: SEER 20, EER 12.5, and HSPF5 8.4. The EER rating and maybe the HSPF5 I could possibly believe, in certain conditions, but I would have a hard time pulling the trigger on a not cheap (relative to window units) system that seems to beg to be mismatched to specific buildings. Yes, I know they are priced hundreds of dollars cheaper than established brands of similar rating.

I hope it serves you well. Please follow up on this unit if you can. Given the lack of real-world performance data, your information would help fill in the blanks for many inquiring minds. Not to mention the other unit of the same brand you already operate.

It is the mod SENA-24HF-Z.
When it gets here I will start a post on it.
I'm going to put it on a concrete pad as I did for my other split.

Last year we were using a very inefficient 10,000btu portable air conditioning unit. The kind that rejects heat through a dryer vent. The problem with this type of unit is it draws air from inside the structure to cool the condenser coils so any time it's cooling air is being drawn in from the outside.
That almost worked.
It's being replaced with a closed loop unit that has almost 2 and a half times more cooling capacity.

I'm thinking a 3/4 ton split, probably not big enough, would work most of the year.
I figured a 1 ton split will likely cool decently on all but the hottest days.
A 1.5 ton should work pretty good.
And a 2 ton removes all doubt.
A 2.5t would just be overkill.
3 ton is just showing off.

I have the SENA-12HF-Z in our 550 sq-ft upstairs master bedroom (west and south wall sun exposure). Here in Houston we have to push its turbo mode quite a bit if we forget to leave it running while we are out.

Documentation is pretty sparse and tech support is rather uninformed (are they really guessing?). That said, with a 24k you may find "auto" mode becoming your default setting. It is the quietest of all the modes and if you run the unit 24/7 it seems to do fairly well at holding temperature. My electric bill runs about $100 most months in my 2500 sq ft house running 5 mini splits totaling 7 ton max capacity. I never have seen max capacity with the inverters...... :)

Yeah Houston gets a lot more humid and a little hotter then where I am.

Yep, that is where my downstairs LG 30K is the superstar. It can remove over a gallon of moisture per hour! Puts my Grees and Senville to shame and they are decent.

Wow I get maybe a gallon a day out of my bedroom 9,000btu inverter split.

The Grees will pull out about half a gallon per hour and my Senville Aura 12k in the master bedroom pulls about a quart and a half an hour. Good old Houston area humidity. You can depend on that.

With dry air feeling cooler, maybe I should move to New Mexico, or maybe just downstairs. Grrrrrr...... :(

OK, I understand your line of reasoning here. Kinda sorta like the other thread about thermostat setback and heat pumps. Rather than do a load calculation or find a unit with well-documented performance specs, just buy an oversized unit. That way, if the unit is overrated by the manufacturer or an extreme day happens, the unit will not fall on its face trying to maintain comfort. During typical operation, the unit can be throttled back towards the efficient performance range, saving energy.

I guess this idea is cheaper than buying a unit that is barely rated to provide the required load 99 percent of the time. Most likely, a smaller unit (especially a value brand product) would be running in it's "not so efficient" range more often. More importantly, the smaller unit wouldn't​ be able to deliver the heat or cooling required on the 1 percent days (or more often if overrated).

Sounds eerily like a few of the HVAC installers in my locale: Oh, you have an R-22 unit? Those are no good anymore. Yes, we can possibly fix it, but what you really need is this new inverter unit that uses environmentally friendly R-1234567. Since the old one wasn't able to deliver the heat every day, we will upsize your unit for you. We have a special this month on a system that is perfect for your home. We can put it in today, all you need to do is sign this paper...

Also I want to be able to turn the unit completely off during the day then crank it up about 1700L and have it actually be able to cool down the house on a 100°F day.
I did the load calculations, I wrote it down on a strip of toilet paper and left it next to the toilet because I have found that's about all they are really good for, says I really only need a 1 ton to 1.5 ton. The price difference between a 1 ton and 2 ton is about 50% more and I consider the 1.5 and 2 ton price difference to be negligible over the long haul.

Based on my observations the traditional air conditioning sizing method appears to focus on picking the lowest cost unit that will keep the house cool when ran continuously even on most of the hottest days of the year.
Since system cost is not my primary concern why size it the old fashioned way?

Plus I'm doing it all. Pouring the concrete pad, running electrical, install the unit, vacuum down the system, charging and firing it up. The AC installer company wants to do an install because their labor charge half to 2/3 of the total price and the repair man likely gets a kickback for selling a unit they have in inventory.

Oil Pan 4,

After awhile when you see how efficient the mini splits are, you may find yourself doing as I do, letting them run 24/7 in auto mode and switch back to heat or cool mode for the bedroom for the night, though with the Senville Aura unit it will try to maintain plus or minus 2 degrees from set point in auto mode so if that works for your area, all the better than fiddling with it.

I have experimented with tuning them off and back on. I have found that I use more energy than just leaving them on all the time.
Now we sometimes turn it down a couple degrees the when the boys come back home the will change it a couple degrees this does save some energy.

The reason I went with a 9,000btu split in the bed room is my wife works night shift so that one runs all day.
The hottest days the room would warm up to about 85'F with a 6,000btu window unit.

We have three Gree 9,000 BTU 27 SEER Terra series. They are a great fit for a bedroom.
They will keep it as hot or cool as you want and do the job quietly enough to still sleep.
These all run 24 x 7.

I gave to agree with your points. They are excellent.