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Is It Possible for Indoor Humidity to Affect Energy Bills?


"It's not the heat -- it's the humidity." While we may not hear that refrain as much as they do in the hot, humid Southern states, homes in our area can be subject to excessive indoor humidity. When that happens, not only do occupants feel uncomfortable, but energy bills may also go up.


Warmer air holds more moisture than cool air. If the relative humidity in your home tends to be more than 50 percent in the summer, you'll start feeling uncomfortably warm and sticky. Perspiration on our skin that normally evaporates and cools us off can't do so effectively in warm, moist air. Thus, we head for the thermostat to turn the air conditioner down. When our homes are less humid, we don't need to run the A/C so low.


It's a good idea to keep an eye on the relative humidity of your home. You can do so by buying an inexpensive hygrometer from a home store. If your hygrometer reads consistently high for humidity, you may have a problem, such as one of these conditions:

  • leaking plumbing
  • leak in the roof
  • clogged condensate drain
  • moisture buildup in unventilated spaces, such as bathroom or kitchen


First, you should fix whatever conditions are resulting in higher humidity, by repairing leaks, having the condensate drain cleaned out and by installing exhaust ventilation to the outdoors in the bathroom or kitchen.

Also, if you're not already doing so, change your HVAC air filter regularly. A dirty filter can prevent your air conditioner from doing its job of removing moisture from the air as condensation. Another potential problem is dirty evaporator coils, which may prevent the proper removal of indoor moisture from the air.

A whole house dehumidifier, installed in the HVAC system, can also help your A/C remove excess moisture from the air. Ask us about the right model for your home.

Visit the Valley Heating, Cooling, Electrical website for in-depth information on indoor humidity and HVAC topic or give us a call at (408) 868-5500.

Our goal is to help educate our customers in the South Bay Peninsula and Santa Cruz areas of California about energy and home comfort issues (specific to HVAC systems).

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