By Krist Matthew, Energy Advisor
Meier, A. (2019, October). The energy costs of moisture. Home Energy, 02.
Fall 2019 Issue
This tech talk is inspired by an article written by Alan Meier in the fall 2019 issue of the Home Energy magazine. I’ll try to summarize the main points, but I highly encourage reading the article in its entirety.
The energy impacts of moisture—such as vapor in the air, or liquid and vapor within building materials and condensed on surfaces—can be subtle, but they add up to big costs.
“More often people don’t talk about a moisture bill like they do for heating and cooling bills, but it does exist and can be potentially large,” notes Meier, who is founder of Home Energy magazine. A moisture energy bill can be complex, since the moisture is dispersed among many devices. However, some of its contributors are easy to spot: inefficient dehumidifiers, and air conditioners that do a poor job of dehumidifying.
Operating patterns for dehumidifiers vary widely, but in mid-Atlantic states, these machines can easily run 2,000 hours/year and consume 1,000 kWh/year. This translates into almost 10% of an average home’s electricity bill. And most dehumidifiers in basements are coupled with a sump pump, which can add to electricity consumption.
Moisture reduces the effectiveness of insulation. Wet insulation can translate to higher heating and cooling bills. Excessive moisture in homes leads to mildew and mold, increases in dust mites and other issues that cause odor and health problems. Additionally, high moisture levels can damage building materials by causing wood to rot and paint to peel. When these costs are put together, the “moisture bill” can approach the heating and cooling bills for many homes. Moreover, this doesn’t include the costs of material damage (or health complaints) from moisture-induced mold, mildew and dry-rot.
Each home’s situation is different, some options to addressing moisture issues include:
- Installing a more efficient dehumidifier
- Installing more efficient ventilation fans and controls, and making sure they vent to the outside
- Encapsulating crawlspaces
- Considering installing a variable-speed air conditioner unit
Meier concludes the article by stating that “Providing thermal comfort and maintaining material integrity in a home is more complicated than just heating and cooling. As a side note, I personally had to address high moisture levels in my home due to location and the building type of my home. My home consists of a walk-in basement connected to a dirt floor crawlspace. I chose to encapsulate the crawlspace and bring it into the thermal envelope of the rest of the house. I can attest to not having to smell moisture from the crawlspace anymore, with the added benefit of not worrying about losing the heat in my basement to the exterior through the crawlspace.”
