Where should a dehumidifier go in a garage?
Put the unit where air can move around it, keep the garage door and windows closed while it runs, and set it near a floor drain or sump if a hose is used. A top-mounted air discharge can sit closer to a wall. In a cool garage, check the lower temperature range and frost protection before settling on the spot.
Start with the garage moisture condition
A garage can be a closed room one hour and an open bay the next. Before choosing a corner, decide how damp the garage is without a dehumidifier. ENERGY STAR ties the capacity you need to two factors: the size of the space and how damp it is without dehumidification. The table below repeats the dampness part of that guidance. Use it as a starting point, then read how much capacity a garage dehumidifier needs and the garage dehumidifier listings that fit the space.
A pints-per-day figure is a capacity rating, not a bucket size. Ratings made under different procedures are not directly comparable: ENERGY STAR explains that a unit rated under the newer, cooler procedure will likely report a smaller capacity than under the older one. Size for the damp condition the garage actually reaches; ENERGY STAR notes it is better to oversize than undersize.
| Condition without dehumidification | Suggested capacity range (pints per day) |
|---|---|
| Slightly to moderately damp, 50% to 75% RH | 20 to 30 |
| Very damp, 75% to 90% RH | 25 to 40 |
| Wet, 90% to 100% RH | 30 to 50 |
Choose a spot that lets air move
Air has to reach the unit and leave it. ENERGY STAR notes that most portable dehumidifiers blow air out of the top and can stand against a wall. If the discharge is not top-mounted, keep the unit away from walls and furniture so air can circulate freely. In a garage, that usually means leaving a gap around the unit and not tucking it into a corner behind stored boxes or a workbench.
Check where the air leaves the cabinet in the maker's specifications before you pick the spot. For more detail, read airflow and clearance needs.
Keep the garage envelope closed while drying
A garage door is the largest opening in most garages. ENERGY STAR advises that doors and windows to the space be closed while the unit runs. If the garage door stays open, the unit is trying to dry air that keeps being replaced by outdoor air. Place the unit away from the door's direct path and make closing the door part of the drying routine.
This does not mean a garage must be airtight. It means the unit works with less wasted effort when the big opening stays shut during a drying session. If the door must stay open for a project, expect the humidity to rise and the unit to run longer.
Plan drainage before you set the unit down
Drainage decides where the unit can sit. If you plan to use a hose, ENERGY STAR suggests placing the unit near enough to a floor drain or sump so you do not need a long, unwieldy hose, and keeping the route out of walkways. A short, direct route is easier to check than a long hose that crosses a path.
If the garage has no drain, plan for bucket emptying before you choose the spot. A unit placed behind a car or under a shelf may be hard to reach when the bucket fills. Read continuous drain setup basics to match the drain plan to the garage layout.
Match the placement to garage temperature
Garages can run cooler than living space. ENERGY STAR notes that if the space is typically below 65°F, a product specified for use at lower temperatures may be worth considering. Frost can form on the condensing coils when the air temperature drops below 65°F, and that can affect performance by causing the compressor to cycle on and off without removing moisture. Some units have an anti-frost sensor that turns the unit off automatically below a set point.
In a cool garage, the temperature limit matters as much as the spot. Read low temperature operation basics before choosing a winter spot.
Set a humidity target and use the humidistat
ENERGY STAR describes the optimum relative humidity for a building as generally between 30% and 50%. A target in that band gives the unit a clear stopping point. Read picking a target humidity level for how to settle on a number.
All ENERGY STAR dehumidifiers include a built-in humidistat, which lets you set the desired relative humidity. Once the room reaches that level, the unit cycles on and off to maintain it. If the unit has no humidistat, or the display does not show relative humidity, a separate hygrometer hung near the unit can show when to switch it on and off.
Expect a little warmth and some noise
Do not be alarmed if the air directly around the unit feels warmer than the rest of the garage. ENERGY STAR notes that while a dehumidifier pulls moisture out of the air, it adds a little warmth to the space around it. That matters in a small garage where the unit sits close to a work area.
Placement also changes how noticeable the unit is. Put it where the sound bothers the fewest people. Read reading noise ratings before you place a unit if the garage shares a wall with a quiet room.
A placement checklist for the garage
Use this order when setting up. First, close the garage door and any windows. Second, pick a spot with free air movement and enough clearance for the discharge design. Third, check that the drain route is short and clear, or that the bucket is easy to reach. Fourth, confirm the unit's lower temperature range fits the garage in the season you plan to run it.
Keep the unit on a stable, level surface so it does not rock. If the garage floor slopes toward a drain, use that slope to keep the hose route short.
| Placement question | What to check |
|---|---|
| Is the door closed during drying? | Close the garage door and windows while the unit runs. |
| Can air move around the unit? | Follow the discharge design: top discharge may sit near a wall, other designs need open space. |
| Is the drainage route short and clear? | Place near a floor drain or sump, and keep the hose out of walkways. |
| Is the garage cool? | Check the lower temperature range and frost protection. |
| Is the unit easy to reach? | Leave room to empty the bucket or check the hose. |
Which to choose
| If you | Look for |
|---|---|
| If you park a car in the garage and need the floor clear | Place the unit along a wall with top-mounted discharge, and route the hose behind the parking line. |
| If the garage has a floor drain | Set the unit close enough for a short hose run, and check the drain before each wet season. |
| If the garage stays below 65°F for much of the year | Look for a unit specified for lower temperatures and with frost protection. |
| If the garage door opens often during the day | Place the unit away from the door's direct path and run it when the door can stay closed. |
| If the garage is only slightly damp | Start with the slightly to moderately damp range in the ENERGY STAR table, and keep in mind that ENERGY STAR calls oversizing better than undersizing. |
Questions people ask
Can a dehumidifier sit against a garage wall?
It can if the unit has top-mounted air discharge. ENERGY STAR notes that most portable dehumidifiers have top-mounted discharge and can be placed against walls. If the discharge is not top-mounted, leave space away from walls and furniture so air can circulate.
Should the garage door stay closed while the unit runs?
Yes. ENERGY STAR advises that doors and windows to the space be closed while the unit runs, so the space is dehumidified as efficiently as possible. An open garage door lets outdoor air back in and makes the unit work longer.
Where should the drain hose go?
Place the unit near a floor drain or sump so the hose can be short. ENERGY STAR warns against a long, unwieldy hose and against creating a tripping hazard. If no drain is nearby, plan for bucket emptying instead.
What if the garage is colder than 65°F?
ENERGY STAR notes that below 65°F, frost can form on the condensing coils and affect performance. A product specified for lower temperatures, or one with an anti-frost sensor, may suit a cool garage better.
What humidity should a garage target?
ENERGY STAR describes the optimum relative humidity for a building as generally between 30% and 50%. A built-in humidistat lets you set a level and the unit cycles on and off to maintain it.
Why does the air near the unit feel warmer?
ENERGY STAR notes that a dehumidifier gives off a little heat while it pulls moisture from the air, so the nearby space gets slightly warmer. That is normal. Keep the unit away from a workbench if the extra warmth is noticeable.