Yes, but only in specific situations—and it may cost you more than it saves

A dehumidifier can reduce the workload on your air conditioner, but only if your AC is already struggling with moisture rather than temperature. If your home is already cool enough but feels sticky, a dehumidifier will help. If your home is too warm, running a dehumidifier alone will not cool it down—and adding one to your AC system uses more electricity overall, not less.

The key difference: air conditioners remove both heat and moisture as they cool. A dehumidifier removes only moisture and actually generates heat as it works. In most homes, your AC is already handling humidity fine. Adding a dehumidifier means running two machines instead of one, which raises your electric bill.

Key Takeaways

  • Air conditioners remove humidity as part of their cooling cycle, so a dehumidifier is redundant in most homes.
  • A dehumidifier makes sense only if your AC keeps the temperature right but the air still feels damp, or if you have a basement or bathroom where AC does not reach.
  • Running both an AC and a dehumidifier together uses more electricity than running the AC alone and will increase your monthly bill.
  • If your AC is not removing enough moisture, the problem is usually poor airflow, a clogged filter, or a refrigerant leak—not a missing dehumidifier.

How air conditioners already remove humidity

Your AC cools air by running it over cold evaporator coils. As warm, humid air passes over these coils, two things happen at once: the air cools down and moisture condenses out of it, the same way water beads on a cold glass. That moisture drains out of your home through a condensate line.

This is why a properly working air conditioner leaves your home feeling dry. You are not paying extra for dehumidification—it is a side effect of cooling. The colder the air gets, the more moisture it loses automatically.

When a dehumidifier actually helps

A dehumidifier becomes useful in three specific cases. First, if your AC keeps your home at the right temperature but the air still feels damp—usually because your AC is oversized and cycles on and off too quickly without running long enough to remove moisture. Second, if you have a basement, crawl space, or bathroom that your AC does not reach well. Third, if you live in a very humid climate and your AC runs constantly but still cannot keep up.

In these situations, a dehumidifier in the problem area can help without forcing your AC to work harder. A basement dehumidifier, for example, does not interfere with your whole-home cooling system.

But even then, you are paying to run two machines. A small dehumidifier uses 300 to 700 watts. Running it eight hours a day costs roughly $7 to $17 per month in electricity, depending on your local rates and the unit's size. That is money your AC was already spending to remove that moisture.

Why adding a dehumidifier to your AC system backfires

If you run a dehumidifier in the same room where your AC is cooling, you are working against yourself. The dehumidifier pulls moisture out of the air, but it also generates heat—typically 5 to 15 degrees warmer than the air it takes in. Your AC then has to cool that warmer air back down, using more energy to reach the same temperature.

The result: higher electric bills with no gain in comfort. You have straightforward added a second machine that your AC must now overcome.

Signs your AC is not removing humidity properly

If your home feels damp even though your AC is running and the temperature feels right, the problem is usually not that you need a dehumidifier. It is that your AC is not working as it should. Check these things first.

A clogged air filter blocks airflow and prevents the AC from running long enough to remove moisture. Replace your filter every one to three months depending on dust and pets. A refrigerant leak means your AC cannot cool the air enough to condense out the moisture—this requires a service call to a technician. Poor ductwork or closed vents can prevent cooled air from reaching certain rooms, leaving those areas humid while the rest of the house is dry.

If your AC is oversized for your home, it cools the air quickly but does not run long enough to remove all the moisture. This is a design problem that a dehumidifier cannot fix—it can only mask it temporarily while costing you more money.

Dehumidifier versus AC: the electricity cost

An air conditioner uses 3,000 to 5,000 watts while running. A dehumidifier uses 300 to 700 watts. Running both at the same time means your home is drawing 3,300 to 5,700 watts instead of just the AC alone. Over a month, that extra dehumidifier running eight hours a day adds roughly $7 to $17 to your electric bill—and that is before the AC has to work harder to cool the heat the dehumidifier generates.

If your AC is already handling temperature and humidity correctly, a dehumidifier is a pure cost with no benefit. If your AC is struggling with humidity, the fix is usually a service call, not a second machine.

When to use a dehumidifier instead of relying on AC alone

A dehumidifier makes financial sense in a few narrow cases. If you have a basement that stays cool but damp, a dehumidifier in that space alone will not force your whole-home AC to work harder. If you live in a climate where humidity is extreme and your AC runs constantly but still cannot keep up, a dehumidifier in the bedroom at night might let you sleep more comfortably without lowering your thermostat further.

The rule: use a dehumidifier only in spaces your AC does not reach well, or only during the hours when humidity is a problem but temperature is not. Do not run it in the same room as your AC thermostat, because it will trick your AC into running longer than necessary.

Frequently Asked Questions

Will a dehumidifier make my AC more efficient?

No. A dehumidifier generates heat as it works, which forces your AC to run longer to maintain the same temperature. You end up using more electricity overall, not less. Your AC is already removing humidity as part of its cooling cycle.

Can I run a dehumidifier and AC at the same time?

You can, but it will cost you more money with no comfort gain. The dehumidifier heats the air while removing moisture, so your AC must cool it back down. This is inefficient. Only run both if the dehumidifier is in a space your AC does not reach, like a basement.

What if my AC is not removing humidity?

Check your air filter first—a clogged filter blocks airflow and prevents moisture removal. If the filter is clean, you may have a refrigerant leak or poor ductwork. Call an HVAC technician to inspect. A dehumidifier will not fix the underlying problem.

Is a dehumidifier worth it for a basement?

Yes, if your basement stays damp despite your AC running. A basement dehumidifier does not interfere with your whole-home cooling system. Expect to pay $7 to $17 per month in electricity, depending on the unit size and how often it runs.

How do I know if my home is too humid?

Comfortable indoor humidity is between 30 and 50 percent. Above 60 percent, you may notice dampness, musty smells, or condensation on windows. A cheap humidity meter from any hardware store will tell you the actual level. If your AC is running and humidity is still high, have it serviced before buying a dehumidifier.