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Dehumidification is really under-explored. If you live in Florida or the Gulf Coast (or similar areas around the world), your home can be at risk of mold and hu

Dehumidification is really under-explored. If you live in Florida or the Gulf Coast (or similar areas around the world), your home can be at risk of mold and humidity damage during shoulder seasons when the AC is not frequently running (not to mention thermal discomfort [1]). And, dehumidification is key to reducing indoor allergens in these climates, particularly dust mites and mold. What I couldn't figure out is if there are any circumstances where running a traditional condenser dehumidifier (whole-house, in the attic) would save you energy/money for the same thermal comfort range. A DoE simulation study I can't find says no, but some HVAC forum posters say that it can, and based on experience I'm inclined to think it could in some circumstances. The desiccant wheel dehumidifiers seem to get a lot more water out per kWh [2], making it a win as seen in this new integrated technology. However, running a floor dehumidifier dumps 800+ watts of waste heat into the space you're dehumidifying, making it impractical for thermal comfort with condensers and maybe even desiccants. I would pay good money for a window-unit dehumidifier that could be used either in apartments or without having to pay for installation and ductwork of a whole-house dehumidifier. [1] https://en.wikipedia.org/wiki/Thermal_comfort#PMV/PPD_method https://en.wikipedia.org/wiki/Thermal_comfort#PMV/PPD_method [2] https://www1.eere.energy.gov/buildings/publications/pdfs/building_america/ns/eemtg082011_a6_laboratory_evaluation_erv.pdf https://www1.eere.energy.gov/buildings/publications/pdfs/bui...

MostlyStable 3y ago
Had a new Heat pump HVAC system installed last year and had them put in a whole house dehumidifier at the same time, since my winter indoor humidity was frequently topping 70%. It keeps the indoor humidity between 40-50% which has noticeably improved the mild-to-moderate mold issues that I had previously and it doesn't seem to consume much power (I haven't been able to obviously note it in my power use graphs the way I can the regular HVAC)
- sokoloff 3y ago
  I also installed a whole house dehumidifier (in New England). It gives a noticeable improvement in indoor air quality, but I can definitely see it on my electric usage. (I wish I could un-see it. It removes a little over 2L/kWh per the spec sheet, but that also means it's using about $2-3/day in a lot of the summer.)
wolverine876 3y ago
> I would pay good money for a window-unit dehumidifier that could be used either in apartments or without having to pay for installation and ductwork of a whole-house dehumidifier. All/most window AC units I've seen have a mode labeled something like 'dry only', which I take to mean 'dehumidify only'.
rainbowzootsuit 3y ago
In the humidity vs thermostat question the literature you are probably looking for is ASHRAE Standard 55.(1) The short answer is that you can feel comfortable at lower humidity and higher temperature. I found a tool to let you play with the parameters.(2) For example the air speed from a fan causes some cooling sensation so the temperature can be higher for the same comfort. The energy use to get there would need to be modeled by measure of the change in cooling degree days vs energy consumption and that is not universal answer across all scenarios because of climate, construction, and ventilation. (1)https://www.ashrae.org/technical-resources/bookstore/standard-55-thermal-environmental-conditions-for-human-occupancy https://www.ashrae.org/technical-resources/bookstore/standar... (2) https://comfort.cbe.berkeley.edu/ https://comfort.cbe.berkeley.edu/

MostlyStable 3y ago

Had a new Heat pump HVAC system installed last year and had them put in a whole house dehumidifier at the same time, since my winter indoor humidity was frequently topping 70%. It keeps the indoor humidity between 40-50% which has noticeably improved the mild-to-moderate mold issues that I had previously and it doesn't seem to consume much power (I haven't been able to obviously note it in my power use graphs the way I can the regular HVAC)

sokoloff 3y ago
I also installed a whole house dehumidifier (in New England). It gives a noticeable improvement in indoor air quality, but I can definitely see it on my electric usage. (I wish I could un-see it. It removes a little over 2L/kWh per the spec sheet, but that also means it's using about $2-3/day in a lot of the summer.)

wolverine876 3y ago

> I would pay good money for a window-unit dehumidifier that could be used either in apartments or without having to pay for installation and ductwork of a whole-house dehumidifier. All/most window AC units I've seen have a mode labeled something like 'dry only', which I take to mean 'dehumidify only'.

rainbowzootsuit 3y ago

In the humidity vs thermostat question the literature you are probably looking for is ASHRAE Standard 55.(1) The short answer is that you can feel comfortable at lower humidity and higher temperature. I found a tool to let you play with the parameters.(2) For example the air speed from a fan causes some cooling sensation so the temperature can be higher for the same comfort. The energy use to get there would need to be modeled by measure of the change in cooling degree days vs energy consumption and that is not universal answer across all scenarios because of climate, construction, and ventilation. (1)https://www.ashrae.org/technical-resources/bookstore/standard-55-thermal-environmental-conditions-for-human-occupancy https://www.ashrae.org/technical-resources/bookstore/standar... (2) https://comfort.cbe.berkeley.edu/ https://comfort.cbe.berkeley.edu/