Best Room Air Conditioners: Reviews by Spec

Window vs Portable Air Conditioners

Window units sit in a window opening and vent heat directly outside. Portable units roll on wheels and use an exhaust hose to a window kit. They are easier to move but often have lower seasonally adjusted cooling capacity than their BTU listing suggests. Choose a window unit for permanent cooling in one room, and a portable for flexibility or when a window unit cannot be installed. See our portable vs window comparison.

Cooling Capacity and Room Size

Cooling capacity is stated in BTU for window units and in SACC for portables. SACC is the seasonally adjusted figure from the Department of Energy procedure for portables. Match the unit to your room size: the 14,000 BTU window picks list 700 and 800 sq ft, while the 10,000 BTU window picks list 450 sq ft. For portables, use the maker's own room figure: the Midea Inverter Duo lists 550 sq ft with a 12,000 SACC, and the Tosot lists 400 sq ft with a 6,200 SACC. Oversizing leads to short cycles and poor humidity removal. Learn more about BTU and SACC ratings and choosing the right BTU.

Energy Efficiency and ENERGY STAR

ENERGY STAR certified room air conditioners meet strict efficiency criteria set by the EPA. They often include variable speed compressors and better sealing materials. Among our picks, the LG Dual Inverter and Midea 12,000 BTU window units carry the ENERGY STAR label. Efficiency also depends on proper sizing and installation. Check the ENERGY STAR criteria for details.

Noise and Features to Consider

Noise matters in bedrooms and offices. The Dreo 740S portable lists a 42 dB noise level, the only noise figure among our picks. Window units with U-shaped designs, like the Midea U-shaped inverter, place the compressor outside the window, which can reduce indoor noise. Look for modes like sleep, dry, and fan-only, plus timers and remote controls. See window AC noise and 3-in-1 modes.

Installation and Maintenance

Window units require a standard single-hung or double-hung window and proper support brackets. Portable units need a window kit and an exhaust hose that stays short and straight. Both types need regular filter cleaning on the schedule in the maker's manual. Always follow the maker's installation instructions. For checklists, see window AC buying checklist and portable AC buying checklist.

How we picked

We ranked these room air conditioners using only the specifications that makers publish. For window units, we compared BTU ratings and room size figures. For portable units, we compared seasonally adjusted cooling capacity, or SACC, because that is the U.S. Department of Energy figure for portables. We also considered ENERGY STAR certification and noise levels where listed. No unit was handled or measured.

How BTU cooling capacity is stated

Cooling capacity for a room air conditioner is stated in British thermal units per hour, usually written as BTU. A window unit's BTU figure is the cooling capacity the maker lists for that model, and it appears on the unit's energy label. Federal rules set the procedure behind that figure, so window units from different brands are rated the same way. For a quick match, ENERGY STAR publishes a room area table that pairs square footage with a recommended BTU range. The table assumes an 8-foot ceiling. If the ceiling is higher, the same floor area may need more capacity (ENERGY STAR room air conditioners).

BTU stands for British Thermal Unit, a measure of heat energy. One BTU is the amount of heat needed to change the temperature of one pound of water by one degree Fahrenheit. In air conditioning, the BTU figure tells how much heat the unit can remove from a room in an hour. The table below shows the capacity needed for common room sizes. These are starting points, not exact requirements. A heavily shaded room or a very sunny room will shift the number, and those adjustments are covered in the next section. It is not the same as the seasonally adjusted figure used for portables, which is explained later. Use the table to find the base BTU, then apply the adjustments that match your room.

Adjusting capacity for sun, shade, kitchens and people

The base table is only a starting point. ENERGY STAR gives four adjustments that change the capacity you should look for. A room that is heavily shaded can use 10 percent less capacity than the table suggests. A very sunny room needs 10 percent more. For rooms regularly occupied by more than two people, increase the capacity by 600 BTUs for each extra person beyond the second. If the unit will run in a kitchen, increase capacity by 4,000 BTUs (ENERGY STAR room air conditioners). These adjustments reflect extra heat from sunlight, bodies, and cooking appliances. They are meant to be applied after you find the base BTU from the table.

• Heavily shaded room: reduce capacity by 10 percent.
• Very sunny room: increase capacity by 10 percent.
• More than two people: add 600 BTUs per additional person.
• Kitchen use: increase capacity by 4,000 BTUs.

For example, a 300 to 350 square foot room normally calls for 8,000 BTU. In a very sunny location, the same room would need more than 8,000 BTU, often the next step up. A kitchen of that size would need 12,000 BTU. The adjustments are additive, so a sunny kitchen with several people can move you up more than one capacity step. After applying all adjustments, round down to the nearest thousand to get the final BTU figure to look for (ENERGY STAR how to choose the right sized window AC). For a step-by-step walkthrough that includes these adjustments, see the BTU sizing walkthrough. For rooms in the 8,000 BTU range, the best 8000 BTU air conditioners page lists current options.

SACC versus the larger BTU figure on portables

Portable air conditioners carry two capacity figures in many listings. The first is the BTU figure the maker states, often a round number like 10,000 or 14,000. The second is the seasonally adjusted cooling capacity, shortened to SACC. Whynter's ARC-102CS manual describes SACC as a representative value in Btu/h worked out under the federal DOE procedure for portables, and federal efficiency rules use the same definition. On a given portable, the SACC figure is usually the lower of the two.

Whynter's manual also explains the gap: models built before 2017 were rated under a different procedure, so a newer unit can show a smaller number while its actual cooling has not changed. When ChillPane ranks portable units, SACC is the only figure used. A portable's BTU figure is not directly comparable with a window unit's BTU, and it is never set against another portable's SACC. Some portables in the catalog list both figures, while others list no SACC at all; for those, the maker does not list one, and it cannot be estimated from the BTU figure. See how SACC and BTU differ for more. For portables in the 12,000 BTU range, check the best 12000 BTU portable air conditioners page, and for 14,000 BTU models, the best 14000 BTU portable air conditioners page.

Why an oversized unit cools poorly at removing moisture

An air conditioner removes both heat and humidity. ENERGY STAR explains that a unit that is too large cools the room before it has had time to take out the humidity, leaving cool, moist air that feels damp and clammy (ENERGY STAR room air conditioners). The Department of Energy's Federal Energy Management Program adds that oversizing leads to poor humidity removal because of excessive on-off cycling (DOE FEMP purchasing guide).

This is why a bigger BTU number is not always better. A unit that short-cycles may cool the air temperature while the room still feels sticky. A properly sized unit runs longer cooling cycles, which allows the coil to stay cold long enough to condense moisture from the air. The most energy efficient choice is a unit sized to the square footage of the space. ENERGY STAR adds that an oversized unit wastes energy and does not cool any better. For a deeper look at the consequences, see problems with an oversized AC. That guide explains the short-cycling pattern and how it affects comfort and efficiency. It also covers signs that a unit is too large for the room.

How to read the room size a maker lists

Many window and portable units include a coverage area in square feet in the maker's listing. This is a general guideline, not a guarantee. Frigidaire notes that its sizing guidelines do not account for vaulted ceilings or a properly insulated room, and recommends contacting a professional for more specific advice (Frigidaire room air conditioner size guide). A room with high ceilings, large windows, or poor insulation may need more capacity than the listed square footage suggests. Treat the listed square footage as a starting point; the ENERGY STAR table itself assumes an 8-foot ceiling.

To measure your room accurately, measure the length and width in feet and multiply them for square footage. Always measure in feet, converting inches to fractions of a foot before multiplying. For triangular rooms, multiply length by width and divide by two. For irregular rooms, break the floor into rectangles and triangles, calculate each area, and add them together (ENERGY STAR sizing guide). When a maker lists a room size, compare it with the ENERGY STAR table and the adjustments above. If the room has a lot of heat gain from windows or poor insulation, the maker's figure may be optimistic. For more on why some rooms are harder to cool, see why rooms are harder. For units rated for 10,000 BTU, the best 10000 BTU air conditioners page shows models with typical coverage figures. For smaller rooms, the small room air conditioner picks cover units rated for the lower end of the ENERGY STAR table.

How window and portable units move heat outdoors

A window air conditioner splits its components across the window sill. The evaporator coil and blower sit on the indoor side, while the compressor, condenser coil and condenser fan sit on the outdoor side. During cooling, indoor air passes over the cold indoor coil, which draws heat from it, and the outdoor fan blows outside air over the hot coil to carry that heat away (ENERGY STAR key product criteria). Because the warm parts are outside the room, a window unit does not need a hose to remove hot air.

A portable air conditioner keeps every component inside a single cabinet that sits on the floor. It cools room air the same way, but the hot condenser air must leave through an exhaust hose. The hose connects to a window kit or sliding door panel, which directs warm air outdoors. The unit draws room air across the evaporator to cool it, then pushes the heated condenser air out through the hose. This design makes portables easier to move between rooms, but the hose and window kit are required for cooling mode. ChillPane lists 74 window units and 64 portable units, each with a stated BTU cooling capacity.

The key difference is where the heat goes. A window unit releases heat directly from the back of the cabinet, which hangs outside. A portable unit releases heat through a hose that must be routed to a window or door. For a closer look at how the two designs compare, see the portable and window comparison or the ranked window air conditioners and portable air conditioners guides.

Single hose versus dual hose portables

A single hose portable has one exhaust hose and no separate intake hose. The condenser needs air to release heat, and that air comes from the room itself. The unit pulls room air across the condenser, then pushes the heated air out through the single hose. A dual hose portable adds a second hose that brings outdoor air directly to the condenser. The condenser uses outdoor air instead of conditioned room air, and the heated air still exits through the first hose.

The difference matters most in humid weather. Whynter's troubleshooting page ties frequent draining to humid air, and for its dual hose models it suggests taking off the intake hose when it rains or when outdoor humidity runs high. For rooms where a two-hose layout makes sense, see the dual hose portable air conditioners guide.

The exhaust hose on any portable has to reach a window kit or sliding door panel to carry hot air outside. Whynter's troubleshooting page asks for a hose run that is as short and direct as the room allows, free of sharp bends, and no longer than 9 feet if it must be extended. A long or kinked hose reduces airflow and makes the unit work harder. For a deeper explanation of the two hose designs, read single vs dual hose designs.

U-shaped and inverter window units

Some window units use a U-shaped or saddle design that brackets the window sill instead of sitting on top of it. ENERGY STAR notes that this design lets you open and close the window where the unit sits, and in most cases the control panel and vent stay inside while the noise-producing compressor sits outside. That can mean less indoor noise and an unobstructed view. See the guide to standard and U-shaped designs for more detail.

Inverter window units use a variable speed compressor instead of a fixed speed compressor that turns fully on or off. ENERGY STAR explains that a conventional compressor works like an on/off switch, while a variable speed compressor can vary its motor speed to continuously control temperature. This allows the unit to run at lower output for longer periods, which can reduce temperature swings and lower noise. Inverter models are often quieter and more efficient. For a ranked list, see the inverter window air conditioners guide.

Some portables use the same idea: Whynter's manual for its NEX inverter dual hose models lists reaching the set temperature sooner and no temperature fluctuations among the inverter's advantages. For how the compressor type works, read inverter versus fixed speed compressors.

Which rooms suit each type

Window units need a standard single-hung or double-hung window with an opening wide enough for the cabinet. LG's installation manual states that the unit is designed for standard double hung windows, and non-window installations such as sleeves or wall openings are not supported. A casement window that cranks open falls outside that design; ENERGY STAR's criteria list casement-only and casement-slider room units as separate types, so check that a model is sold for that window. Renters who cannot modify a window frame may prefer a portable unit, which sits on the floor and only needs a window kit that closes into the sash without permanent changes. See which windows accept a window unit for more.

Portable units are more flexible for rooms with sliding windows or doors, because the window kit can be installed vertically in a slider. Whynter's manual shows installation in a sliding window or door, with the foam seals and window slider adjusted to fit the opening. A portable unit can also be moved between rooms, as long as each room has a suitable window or door for the exhaust hose. However, a room with no window or exterior door cannot be cooled by a portable unit, because the hot air must go somewhere. For a room with a sliding door, see venting through a sliding door.

The choice often comes down to the window type and whether you can mount a unit. A window unit keeps its compressor outside, so it is often quieter indoors, but it blocks part of the window and requires a compatible opening. A portable unit takes up floor space and needs a hose, but it works with more window types and can be stored away when not in use. Renters and people with casement or slider windows often find portables the only practical option.

• Renters: portable units avoid permanent window mounting, but still need a window kit.
• Casement windows: a standard window unit does not fit; look for a model sold as casement-only or casement-slider, or a portable whose window kit can seal the opening, and check the maker's instructions.
• Sliding windows or doors: portable units with a vertical window kit are often the only option.
• Rooms with no window access: neither window nor portable units work, because both need to exhaust heat outdoors.

Window and portable at a glance

This table summarizes the main practical differences. Window units keep the noisy parts outside and free up floor space, but they demand a compatible window and block part of the view. Portable units are easier to set up and move, but they use floor space and require an exhaust hose that must stay connected during cooling. The right choice depends on your window type, whether you can mount a unit, and how much floor space you can give up.

What this site does not cover

ChillPane's catalog covers window and portable room air conditioners with a stated BTU cooling capacity. Through-the-wall units and ductless mini split systems are not included, because they require different installation methods and are not room air conditioners in the same sense. If you need a unit that mounts through a wall sleeve, you will need to look outside this site's listings. The ranked guides here focus on the two main types that sit in a window or on the floor with an exhaust hose.

CEER and EER: what the numbers mean

CEER, or combined energy efficiency ratio, is the efficiency figure shown on federal labels for room and portable air conditioners. EER is the energy efficiency ratio at a single cooling condition. The two are not interchangeable. A Whynter ARC-102CS manual lists a CEER of 6.9 and an EER of 9.55 for the same unit, so a lower CEER does not mean the unit is less efficient than its EER suggests. Compare CEER to CEER, not CEER to EER.

A federal purchasing example shows why CEER matters. A unit with a CEER of 15.4 used 584 kilowatt-hours per year, while a less efficient unit with a CEER of 10.9 used 826 kilowatt-hours per year. Higher CEER means less electricity for the same cooling. For window units, check the CEER on the label. How CEER is rated and federal efficiency standards give more detail.

The federal labeling rule requires CEER as the energy efficiency rating for both room and portable air conditioners. When comparing models, use the CEER figure from the label or the maker's published specifications. A higher CEER indicates a more efficient unit under the DOE rating method. Do not compare a window unit's CEER with a portable unit's CEER directly if the portable has a seasonally adjusted cooling capacity, because the rating conditions differ.

What ENERGY STAR certification requires

ENERGY STAR certified room air conditioners must meet a minimum CEER that depends on capacity and whether the unit has louvered sides. The program also requires better sealing materials and clearer instructions to reduce air leaks. ENERGY STAR room AC criteria explains the specifics.

Certified units often include variable speed compressors, which adjust output instead of cycling fully on and off. This can save energy and run more quietly. Many also offer connected features for scheduling temperature changes. Best ENERGY STAR window air conditioners lists window units with this certification.

ENERGY STAR states that certified room ACs use 9 percent less energy than standard models. Proper sizing matters for efficiency too, as the section on oversized units explains.

Settings that reduce energy use

Energy Saver or Eco mode turns off the compressor and fan when the set temperature is reached. On LG window units, the fan then wakes about every 3 minutes to sample the room. Eco and Energy Saver mode explains the differences.

Sleep mode raises the set temperature in small steps during the night, and the quiet running section below lists the LG and Midea steps. What sleep mode does has more.

Timers let you delay start or stop. LG window units offer 1 to 24 hour delay on and off. Whynter portables have a 24 hour programmable timer. Set the unit to turn on before you arrive home, or off after you leave. Auto mode on Whynter portables selects cooling or fan-only operation based on the set temperature and room temperature, and you cannot adjust the fan speed in that mode.

Thermostat habits: set the temperature only as low as needed. Whynter's troubleshooting page describes a 5°F temperature cushion, so a portable keeps cooling until the room is within 5°F of the set point.

Sealing gaps and window kits

According to ENERGY STAR, a poorly installed unit can allow air leakage equivalent to a 6-square-inch opening. Use the foam and insulation materials included with the unit. For window units, the side panels and sash seal must be tight. Sealing window AC side panels covers this.

Portable units use a window kit with foam seals. Whynter manuals describe adhesive foam seals A and B for the window frame, and non-adhesive foam seal C between the window sashes. Midea window units include foam strips to block the gap between upper and lower sash. Sealing the window kit gives step-by-step guidance.

LG manuals note that heatproof foam between the sashes improves cooling capability. A small gap lets warm outside air enter and forces the unit to work harder. Check the seal each season. Rooms harder to cool explains why gaps matter.

Shading windows and placing the unit

Direct sunlight adds heat to the room, which is why ENERGY STAR's sizing adjustments include a step up for very sunny rooms. Closing curtains or blinds reduces the load, and Whynter's troubleshooting page gives the same advice to limit direct sun. Sunlight and heat gain explains the role of windows and insulation.

LG window unit manuals say to install the unit out of direct sunlight. For portables, the hose advice in the hose design section above applies here as well. Venting a portable AC has more.

Keep the area around the unit clear. LG manuals say not to block side and top louvers, and to keep 20 inches clear behind the unit. Whynter portable manuals say to keep at least 12 inches from the nearest wall. This allows heat to leave the condenser. Window AC checklist includes installation tips.

Keeping the unit efficient over time

A dirty air filter blocks airflow and reduces cooling capacity, so filter care comes first. The filter care section further down lists each maker's schedule, from LG's twice-monthly checks to Midea's monthly ones, along with the reminder lights some models use.

At the end of the cooling season, window units come out of the window and portables are drained and dried before they go into storage. The seasonal storage section below gives the Frigidaire, Midea and Whynter steps.

Keep the condenser coils and side louvers clear of debris. LG's manuals warn that restricted outside air greatly reduces cooling efficiency, and they suggest cleaning the cabinet with mild soap and lukewarm water.

Bedrooms: capacity range and rated noise

For a bedroom of 100 to 350 square feet, the ENERGY STAR table above calls for 5,000 to 8,000 BTU per hour, depending on the exact size. 24 units in the catalog sit in the 5,000 to 6,000 BTU band, which covers many smaller bedrooms. For a dedicated bedroom guide, see bedroom window units.

Noise matters more in a bedroom than in a living room. The U-shaped cabinets and variable speed compressors described earlier are the two design points ENERGY STAR links to quieter running. For a closer look at these designs, see quieter window designs. Where a window unit is not an option, a few portables in the catalog list a noise figure of 42 dBA.

A window unit in the 5,000 to 8,000 BTU range stays out of the way and sends heat straight outside. A portable can serve a bedroom without a suitable window, but its hose and compressor sit indoors, so its listed noise figure deserves a close look. The portable picks for bedrooms are ranked by SACC.

For sleep, the sleep mode and fan settings in the quiet running section below matter as much as the cabinet design.

Small rooms and home offices

For a small room or home office of up to 250 square feet, the ENERGY STAR table points to 5,000 or 6,000 BTU per hour. 24 catalog units fall in that band. See small room picks for a focused list.

In a small room, the oversizing problem described earlier is easy to run into, so move up a size only when one of the ENERGY STAR adjustments calls for it. A portable unit with a listed SACC figure can also work, but check that its seasonally adjusted capacity fits the room rather than relying on the larger listed BTU number.

Placement matters in a small room. A window unit should sit out of direct sunlight, with nothing blocking its side louvers, as LG's manuals describe, and Midea's FAQ lists curtains around the unit among the things that restrict airflow. For a home office, a unit with a timer or sleep mode can help reduce energy use during work hours.

A portable unit can be moved between a small office and another room, but each room needs a window kit for the exhaust hose, routed with the same care described in the hose design section. For a small room, a single hose portable unit may be enough.

Large rooms and open living spaces

For a large room or open living space of 450 to 700 square feet, the ENERGY STAR table calls for 12,000 to 14,000 BTU per hour, with larger steps above that. 56 catalog units are listed at 12,000 BTU or more. See large room picks for a ranked list. For window units only, see window units for large rooms.

Open living spaces can pick up heat from sunny windows, cooking and extra people, so the ENERGY STAR adjustments listed near the top of this page matter most here. Applying them helps avoid an undersized unit that runs constantly without reaching the set temperature.

A large room may need air pushed to the far side. LG's manuals describe adjusting the horizontal airflow direction, which helps aim cool air across an open space, and Frigidaire's louver advice in the fan settings section applies too. A portable can circulate air as well, but its hose still has to reach a window.

For a living room, a window unit rated at 12,000 BTU or 14,000 BTU is often the most direct solution because it exhausts heat outside without taking up floor space. Portables remain an option, with SACC as the figure to compare. Some portable units listed at 14,000 BTU have a seasonally adjusted figure of 10,000 BTU, which changes how they fit a large room. See portable units for large rooms for details.

Portable units for large rooms and their SACC figures

Portable units for large rooms often carry a high BTU figure on the box, but SACC is the number to use. Federal efficiency rules define it as the seasonally adjusted cooling capacity in Btu/h, worked out under the DOE procedure. The catalog shows both figures where the maker lists them. 64 portable units are listed in the catalog, and not all of them include a SACC figure.

A portable listed at 14,000 BTU may carry a SACC of 10,000 or 12,000. The Midea Inverter Duo 14,000 BTU Portable lists 12,000 SACC, for example, while the Dreo 516S 14,000 BTU lists 10,000. Where the maker gives no SACC, that unit's BTU figure is never set against another portable's SACC. See portable large room guide for a ranked list based on SACC.

Whether a portable uses one hose or two is a design detail the maker states, and the hose design section above explains how the two layouts differ. For more on hose designs, see single vs dual hose.

When comparing portables for a large room, line them up on SACC alone. Every SACC figure comes from the same DOE rating method, which is what makes one portable's figure comparable with another's.

Matching the room type to the unit type

Window units are usually the first choice for bedrooms, small rooms, and large rooms with a suitable double hung window. They exhaust heat directly outside and do not take up floor space. The catalog includes window units from 5,000 BTU to 24,500 BTU, covering rooms from 150 square feet to over 1,500 square feet. For a full list, see window units.

Portable units are useful when a window unit cannot be installed, such as in a room with a sliding window or a window that cannot support the weight. They sit on the floor and use a hose to exhaust heat through a window kit. The catalog includes portable units with listed BTU figures from 7,500 to 16,000, but the SACC figure is the one to compare. For a full list, see portable units.

A living room or open space often suits a window unit because it needs no floor clearance. A portable can still serve a large room if a window sits close enough for a short hose run, since the hose run should stay short, as the hose design section explains.

For a bedroom, noise is a key factor, and the design points above apply. Among portables, the Hisense HAP0825TWD 8,000 BTU and the Dreo 740S 14,000 BTU both list 42 dBA, the figure to compare when a window unit will not fit.

Brands we list and what their units share

The site's brand guides collect the listed window and portable units from Midea, LG, Frigidaire, and BLACK+DECKER. Because every product on ChillPane comes from maker specifications, the guides let you compare capacities, room size figures, and features without leaving the catalog.

The catalog includes 27 Midea units, 21 LG units, 11 Frigidaire units, and 12 BLACK+DECKER units. Each guide groups the listed models from that brand so you can compare them side by side.

Each brand guide groups the listed models by type and capacity, so you can see at a glance which units are window and which are portable. The guides also note when a model carries ENERGY STAR certification or uses an inverter compressor, which helps when you are comparing features across a brand.

Midea's listed units include both window and portable designs. Several Midea window models are sold as inverter or U-shaped units, and some list ENERGY STAR certification. The portable models range from compact units to Duo inverter designs. See the Midea room air conditioners guide for the full set.

LG's listed units also span window and portable types. Some LG window models are sold as dual inverter units, and a few list ENERGY STAR certification. The portable models include smart and dual inverter options. The LG window and portable units guide groups them by capacity and feature.

Frigidaire's listed units include window and portable models, with inverter window units among them and ENERGY STAR certification listed for an inverter window model. The Frigidaire room air conditioners guide shows how the brand's models compare.

BLACK+DECKER's listed units include both portable and window models. The portable units cover a wide BTU range, and the catalog lists SACC figures for many of them. The BLACK+DECKER portable and window units guide covers the brand's lineup.

Window kits, mounting and drainage

Window unit mounting

Window units are designed for standard double-hung or single-hung windows. LG's manual for the LW1022FVSM states that a standard single-hung or double-hung window is required, and that non-window installations are not covered. The manual also says to install the unit with the bottom between 30 and 60 inches above the floor and tilted so the back is about 1/4 inch lower than the front. That tilt lets condensed water move toward the outside.

Midea's MAW06R1WWT-T manual asks for a pitch to the rear of about 5/16 inch, which it says is needed for proper condensate management and drainage.

As the sealing section notes, ENERGY STAR links poor installation to air leaks. The included foam strips and side panels are meant to close those gaps. Midea's window manual describes cutting the sash seal to fit between the upper and lower sashes, and LG's manual says to use the heatproof foam to fill the space between the sashes.

Portable window kits

Portable units use a window kit instead of sitting in the window. The parts list in Whynter's ARC-102CS manual includes a window slider kit, adhesive foam seals for the window frame, a non-adhesive seal for the gap between the sashes, and a security bracket. Whynter's troubleshooting page adds that the slider kit can be cut down for a narrow window, as long as the hose cut-outs are left intact.

The same troubleshooting page answers two common setup questions: an extended hose should stay within 9 feet, and the window screen can stay in place when the slider kit goes in.

Drainage

Drainage differs by type. Window units send most condensate to the outdoor section, as the water and condensate section below explains, while portables collect it in an internal pan.

On the ARC-102CS, Whynter notes that running dry mode without venting the hose to the outside can mean more frequent draining.

For portable units, the window kit's foam seals close the gaps around the slider, as the foam strips do between window sashes.

Filters and seasonal storage

Filter care

Filters need regular attention because trapped particles block airflow. LG's manual for the LW6024RSMX says to check the filter at least twice a month and wash it in lukewarm water below 104°F. Frigidaire's support page describes removing the filter from behind the front grille, washing it with warm soapy water, and letting it dry completely before reinstalling. Midea's window manual says to check the filter at least once a month.

Portable units need similar filter care. Whynter's ARC-147WF manual says a filter light comes on after 250 hours of operation as a reminder to clean the filter, and Whynter's troubleshooting page says to clean the washable pre-filter and change the carbon filter when the filters are dirty.

Many units have a filter reminder light that turns on after a set number of operating hours. On the MAW06R1WWT-T, Midea's Check Filter light illuminates after 250 hours of operation, and you press the Filter button to reset it after cleaning. LG's manual for the LW6024RSMX describes a similar Clean Filter LED.

Seasonal storage

At the end of the season, storage protects the unit. Frigidaire's support page says to remove the window unit carefully, cover it with plastic or return it to the original carton, and store it in a dry location in its normal bottom-down position. Midea's portable FAQ says to drain the unit completely, clean any moisture, and cover it with non-reactive plastic to keep dust out.

Whynter's manual for the ARC-0850XP recommends draining the water tray, then running the unit in fan mode for half a day in a warm room to dry the interior, and cleaning the filter before putting the unit away. The manual also suggests storing the unit in a cool, dark place away from direct sunshine or extreme heat.

Window units are typically removed and stored indoors for winter, while portable units can be stored in a closet or basement after draining and drying. Frigidaire's support page says to keep the unit in its normal bottom-down position, not on its end, face, or rear, to protect against rust and damage to electrical connections. The EPA notes that drying damp areas quickly helps prevent mold growth, which is why draining and drying a portable unit before storage matters.

A checklist for choosing your next unit

Start with the room type because window and portable units have different installation requirements. A window unit needs a suitable double-hung or single-hung window, while a portable unit needs a window or sliding door for the exhaust hose. Once you know the type, the brand guides can narrow the list by features like inverter compressors or ENERGY STAR certification.

• Match the room type first. A window units guide covers models that sit in the window, while the portable units guide covers units with an exhaust hose.
• For a bedroom, the bedroom window guide focuses on window units in the bedroom capacity range.
• For a small room or home office, the small room guide lists units rated for smaller spaces.
• For a large room or open living space, the large room guide covers higher capacity window units, and the portable models for big rooms ranks portables by SACC.
• For a living room, the picks for large rooms start at 12,000 BTU.

After you have a shortlist, check the maker's room size figure and the unit's BTU or SACC rating against your room. The window unit buying steps and portable unit buying steps pages walk through the remaining details, such as window dimensions and hose length.

Getting a room air conditioner ready before the first hot week

Before the first hot stretch, the maker manuals describe a short set of checks that need no tools. Start with the air filter, cleaned the way the filter care section above describes. A clean filter lets air move freely, which the makers tie directly to cooling performance. start-of-season checklist walks through the full routine.

Next, check the installation against the sun and clearance points in the placement section above. Midea's window unit manual says the side louvers and the rear of the unit must have clear air space for heat removal. If the unit sat in storage, check that no debris is wedged in the fins and that the case is dry before plugging it in, as Midea's FAQ advises. Cleaning a room AC filter covers the filter step in more detail.

Window units also need the right tilt. LG manuals specify a slight tilt so the back is lower than the front, about 1/4 inch on some models and about 1/2 inch on others. Midea gives its own rear pitch figure, listed in the mounting section above. This tilt lets water move toward the outside instead of the room. tilt for drainage explains why that slope matters.

Quiet running and sleep settings

Noise level depends partly on the design and partly on the fan speed. The design side, U-shaped cabinets and variable speed compressors, is covered earlier on this page. LG's manuals say that if the unit sounds too loud, setting a lower fan speed is the first adjustment. Midea's FAQ says a window unit should be audible when running but not louder than speaking volume. noise from a window unit breaks down what you hear indoors and outdoors.

Sleep mode is designed to reduce noise and shift the temperature while you sleep. LG's manual describes sleep mode as keeping operating noise to a minimum and turning the air conditioner off after a set time. In that mode, the setting temperature increases by 2°F after 30 minutes and another 2°F after another 30 minutes, up to 4°F from the preset. Midea's manual describes the same two steps, then holds the new setting for 7 hours before returning to the original one. Whynter's portable manual says sleep mode gradually increases the set temperature, decreases the noise level, and conserves energy. sleep mode explained has the full sequence.

For a bedroom, a lower fan speed and sleep mode together reduce the most noticeable sound. Some window units also have a display dimming or light off function, which LG's manuals describe as turning off the control panel lights. If quiet is a priority, the U-shaped window designs page explains why those units can be quieter indoors.

What to expect from water and condensate

Window units collect moisture from the air and use it in the outdoor section. GE's support page says a window air conditioner has a slinger ring around the rear fan blade. The fan picks water up from the bottom pan and throws it against the condenser coils, which improves efficiency and removes some condensation and rain water. Water can collect in the base pan and may overflow and drip outside during high humidity or rainy days, which GE calls normal operation. drain plugs and water trays covers the parts involved.

Frigidaire's support page says water dripping outside is a normal function, especially during periods of excessive humidity. If condensation needs to be directed, window units have a key hole drain in the bottom for a 1/2 inch drain hose. The page warns never to drill holes into the bottom of the unit to remove water. If water is dripping inside the room during cooling, Frigidaire says that points to improper installation. Midea's FAQ says the unit should be tilted properly so condensed water flows to the back, where the outdoor fan uses it to cool the condenser. The same slope mentioned earlier applies here.

Portable units handle water differently. Midea's portable FAQ says water accumulates in an internal drain pan, then evaporates and goes out the exhaust hose as water vapor. In humid environments, the unit occasionally needs to be drained by unscrewing the drain cap and catching the water. Whynter's portable manuals say that when the internal drain pan becomes full, the unit beeps eight times and shows a P1 code, the cooling or dehumidifying action stops, and the fan may continue. how portable ACs handle water explains the evaporation path, and portable AC full tank shutoff covers the full tank message.

For dry mode or high humidity, Whynter's manuals describe a continuous gravity drain option: attach the included drain hose and place the open end over a floor drain or bucket, keeping the hose straight and directed downward. The same manuals say the continuous drain relies on gravity only, so a hose with kinks or bends will not drain correctly.

Temperature settings and fan speeds for comfort and energy

The makers' energy saver modes change how the fan and compressor cycle. ENERGY STAR's key product criteria say that in energy saver mode, an air conditioner limits fan operation when the compressor turns off, and this is the default mode when the unit is turned on. Midea's FAQ says energy saver mode turns off the fan at the same time the compressor shuts off, then the fan turns on intermittently to check the room temperature. Energy saver settings has the details.

Fan speed affects both comfort and sound. Whynter's portable manual notes that the difference between fan speeds is not very noticeable when the compressor is on, and suggests setting the unit to fan only mode to hear the difference between high and low. Midea's FAQ says auto mode selects the fan speed based on the amount of cooling needed, varying from high to medium to low. A higher fan speed moves more air past the cooling coils, which can help when the room is warm, but it also makes more sound. fan-only operation explains when to run the fan without cooling.

For comfort, the makers also recommend using the louvers and closing the room. Frigidaire's not cooling page says to position the louvers for better air distribution and check for air deflecting back into the unit from a wall or ceiling. Whynter's troubleshooting guide says to close and insulate windows and doors, reduce heat-producing appliances, and turn the air conditioner on earlier instead of waiting until the hottest point of the day. Adding a fan to circulate air is another suggestion from Whynter and ENERGY STAR. These steps help the set temperature stay steady without setting it extremely low.

When a unit seems not to cool: no-tool checks

Start with the basics. Midea's FAQ says to check that the unit is in cool mode and the target temperature is below the room temperature, then listen for the compressor hum. Frigidaire's support page says the air conditioner drops the temperature of the air it pulls in by 17°F to 20°F before blowing it out, so if the unit is blowing cold air, it is working properly. Frigidaire's support page also says that if the room is too big for the unit, cooling may be inadequate, which is a sizing issue rather than a fault. why a room AC isn't cooling has a longer list of checks.

Airflow restrictions are the next common cause. Frigidaire says to make sure nothing is blocking the entire front or back of the unit, and that the side louvers are not covered. Midea's FAQ says to check for curtains around the unit, leaves blocking the vents, and a dirty filter. Whynter's troubleshooting guide asks for open space around the air intake and filter area, plus the short hose run covered earlier. A weak airflow from the vent or through the fins is a sign to clean the unit, as Midea's FAQ states. fan on without cooling covers the case where the fan spins but cooling does not happen.

Ice on the coils can also stop cooling. Frigidaire's icing page says a dirty filter can prevent the unit from pulling in air, which leads to icing. The page says to shut the unit off, clean the filter, and wait for all ice to dissipate before restarting. Midea's manual says that if the outdoor temperature is below 64°F, set the unit to fan only mode to defrost the coil. LG's manual says to set the mode control at high fan or high cool if the cooling coils are iced over. ice on the coils explains what to do when frost appears.

If these checks do not resolve the issue, the makers say to contact service. Frigidaire's pages say to contact support if the problem continues after the basic checks. Midea's FAQ says if a protection code repeats, call for service. Whynter's manuals say to contact customer support if a full tank message remains after draining. No tools are needed for the checks above, and the owner's manual gives the requirements for anything beyond them. Always follow the manual for your model.