Compact, portable dehumidifiers use a lot of energy, and now some are connected with house fires. But there are greener options.
Before we talk about alternatives to energy-sucking dehumidifiers, here's a video sample of some of the controversy surrounding these machines.
The fact is that dehumidifiers, like window air conditioners, tend to be brute-force machines that require a lot of energy to accomplish the task of extracting moisture from ambient indoor air. Better options exist.
The Cost of Stealing
Most people end up with dehumidifiers in their basement, especially when thy trying to "steal" living space for extra rooms in an existing home. In my opinion, below-grade living spaces are almost never worth the trouble. Unless you live in an arid climate with a perfectly waterproofed and designed foundation, on top of a hill--moisture will almost inevitably find its way in. That means you will have to mechanically remove the moisture, down to a level of about 55% relative humidity, for as long as you own the home. In energy costs that could amount to up to $30 a month to run the noisy unit.
I've personally had a run-in with a near-fire caused by dehumidifier. I ran a 14-gauge extension cord to the unit, and the plug on the extension melted and caught flame. That gauge of wire couldn't handle the power drain. That was my user error—but if I made this simple mistake, how many other less informed buyers will do the same?
Here are five ideas to help you get rid of your dehumidifier, or build your space so you never need one. If you MUST refinish your basement (an area better suited for keeping mechanicals from freezing in cold climates, or storing root vegetables...), here are your options.
1. Building new. New construction offers your best chance to create a dry basement that won't need much dehumidification. Apply a vapor barrier beneath the slab. Add drainage planes to all exterior walls, along with drainage pipes to carry water away. Go "above and beyond" with every detail of waterproofing, and don't cut any corners.
2. Remodeling: frame and insulate with water-resistant (non-organic) materials. Specify rigid foam insulation. Avoid drywall, wood flooring, paneling, or untreated 2x4s. I would also avoid metal studs. They won't mold but they can rust very quickly and stain everything they touch. Look into plastic lumber for both framing and wall sheathing, but make sure it's made from recycled HDPE or something other than PVC, with no organic fillers.
3. Avoid carpets, especially organic ones. I say that reluctantly, because I like organic materials. But not below grade. If you're dead set on carpet, you'll want synthetics. However, many plastic or nylon-based carpets create offgassing problems, or tend to burn very rapidly in a house fire. Carpets a really a no-win scenario in high-humidity areas.
4. Switch to a hybrid hot water heater. This is my favorite option. Some new water heaters are designed to extract heat from ambient air. As a side effect, they also remove a lot of moisture. The upside is that if you locate one in the basement, the power you use to heat your household hot water will do double-duty removing moisture at the same time. Most models are very quiet and will help you save significantly on energy use for hot water.
5. Elevate and aerate the floor. There are many products and systems out there to help you do this. The goal is to create an airspace beneath the flooring, so that if and when the concrete wicks moisture into the home, it has someplace to go.
If you must continue to use a dehumidifier in the bottomless pit of moisture that is your basement, look for a model that is Energy Star certified. Install a dedicated circuit and 20-amp outlet so you need no extension cord. Elevate the unit and attach a gravity fed-hose that runs to a cellar drain or sump. And hope the weather cooperates.
Image: Novaceram elevated flooring