Whole house dehumidifiers

“Whole house dehumidifier” is used for two things that share almost nothing except the words.

The ducted kind is a sealed box that lives in a mechanical room or hangs from the joists, is plumbed into the ductwork of your forced-air system or into its own short duct run, drains to a floor drain or a condensate pump, and is controlled by a humidistat on a wall. You do not see it, you do not empty it, and you do not carry it up the stairs in October. The Aprilaire AprilAire E130 Pro 130-Pint Whole-House Dehumidifier with Model 76 Control in our corpus is this kind, at $2412.94 for the appliance on its own.

The standalone kind is a high-capacity box on castors that plugs into a normal outlet, drains through a hose, and moves its own air within whatever space it is standing in. Several of these are sold as “whole house” and some of them can be ducted, but nothing about them requires a contractor. The 160-pint unit in our corpus sits here, at $1049.97.

The distinction matters because it decides what you are actually buying. Capacity is not the difference between these classes — as the table below shows, the most expensive machine here is not the most capable one. What the ducted unit sells you is distribution and control: dry air delivered to every room through ducts you already own, at one setpoint, with nothing visible and nothing to empty.

A ducted dehumidifier is not a purchase, it is a job. It has to be hung or set with clearance for service, connected to supply and return ductwork with the right collar sizes, balanced so that it neither starves the furnace nor short-circuits its own air, given a condensate path that runs downhill to a drain or through a pump, wired to a dedicated circuit, and tied to a humidistat that is placed somewhere representative rather than next to a bathroom door.

We are not going to publish an installation figure, because we do not have one. That work is priced locally, varies with whether ductwork already exists and what your mechanical room looks like, and every number we could put here would be invented. What we can say is that the appliance price is a floor rather than a price, and that the decision therefore turns on a cost this site cannot produce for you. Get two quotes before you get attached to the idea.

There is one piece of evidence in our own data worth reading, though, and it points in a consistent direction. The ducted units in this corpus move roughly 50 units a month on Amazon between them, and the Aprilaire AprilAire E130 Pro 130-Pint Whole-House Dehumidifier with Model 76 Control carries 26 ratings in total. The portables sit at around 3,000 a month each and 22,300 ratings. These are not really retail products; they are contractor-channel equipment with a retail listing attached. That has a practical consequence for you as a buyer: the crowd-sourced evidence base you would normally lean on barely exists here, which is a reason for caution rather than a reason to assume the worst.

Portables are sold on one number. Ducted units are sold on two, and the second one is where sizing goes wrong.

Moisture removal is the pints-per-day figure, tested the same way for both classes since the DOE moved the test condition from 80°F to 65°F in 2019. That change is worth knowing about here more than anywhere else, because whole-house sizing charts skew old and contractor rules of thumb skew older still. A 130-pint ducted unit today would have been labelled roughly 183 pints before 2019. One listing in our corpus writes DOE 65PPD directly into its own product title, which is the correct thing to do and is also the only one of these units that bothers.

Airflow is the number portables do not have. A ducted unit only delivers its rated removal if it is moving its rated volume of air, and that depends on duct diameter, run length and how it is tied into an existing system. It is a design decision, not a shopping decision, and it belongs to whoever is doing the install. If a contractor quotes you a machine without discussing where the air is coming from and going to, that is a signal.

The third thing that changes: you size per zone, not per house. Capacity does not spread across a floor plan the way a single number implies. A machine in the basement dries the basement, plus whatever share of upstairs air actually circulates down to it. Two portables in two zones are not “one 160-pint machine” — they are two machines each of which has to clear its own zone. The ducted unit is the one case where a single number genuinely applies to the whole floor plan, and only because the ducts are what carry it there.

There is a real case for these machines, and it is not the case the marketing makes. It is worth the money when several of the following are true at once:

If that is your house, the Aprilaire AprilAire E130 Pro 130-Pint Whole-House Dehumidifier with Model 76 Control is the unit in our corpus with the highest tested capacity in the ducted class, at 130 pints a day (183 old scale) — enough margin that a badly judged dampness band will not come back to bite you. Be clear-eyed about the evidence, though: it carries 26 Amazon ratings in total. That is a thin base to lean on, we have never run one, and the number that actually decides whether this is a good purchase — the installed price — is one we cannot give you.

If your moisture problem is one crawl space, you do not need a whole-house dehumidifier and you should not buy one. A crawl space is a sealed, unconditioned zone with its own temperature and its own continuous moisture source in the ground. Ducting a house unit into it fights the house’s conditioning rather than working with it, and it is the most expensive possible way to solve a problem that a single dedicated unit and a sheet of polythene solve better.

If your problem is one basement, the same applies. That is a single-zone job, and a single unit sized to that zone finishes it. The reason people end up on this page anyway is usually that the basement smell reaches the rest of the house, which reads like a whole-house problem and is not one — dry the source and the smell goes with it.

If you have not measured anything yet, buy a hygrometer before you buy a dehumidifier. Fifteen dollars and a week of readings in the worst corner will tell you whether you have a whole-house problem or one damp room, and that answer changes the budget by a factor of ten. There is no version of this decision that gets better by being made faster.

The honest ranking here is that most people who search for a whole-house dehumidifier are describing a symptom, not a system. Work out the number for the space that is actually wet — the size calculator does it on both rating scales — and see whether the answer is still a whole house.

We have never installed or run any dehumidifier on this page, and we are not going to write that we have. What that costs us is the claim every competing page makes. What it buys is that everything asserted here is checkable: the capacities are the manufacturers’ own tested figures, the prices are a dated snapshot, and the sizing arithmetic is published in full.

The gaps are real and worth stating. We have no installation quotes, and on a ducted unit that is the largest unknown in the decision. We have no long-term reliability data on equipment that is meant to last fifteen years and has been on sale for a fraction of that. We cannot compare running costs across these classes, because efficiency figures are published inconsistently on retail listings and comparing a ducted unit’s consumption against a portable’s ignores that they are moving different volumes of air to different places.

For the questions this method cannot reach — how a contractor-installed unit behaves in year five, whether a particular install was worth it — the HVAC trade forums and the owner threads on Reddit hold more useful material than any buying guide, this one included, and we earn nothing when you go and read them.