What temperature should your house be to prevent mold?

Author: Hayden Kris  |  Last update: Friday, February 27, 2026

Keeping the air conditioner set at 78 degrees or lower prevents mold buildup in the summer. Even when leaving for a few days or vacation, don't set it above 80. A higher setting won't provide enough dehumidification from the cooling process to prevent spores from growing.

Does a warm house stop mold?

Heat actually does help a lot, cold walls will cause moisture in the air to condense on the walls and the mould needs that moisture to grow and spread. The best thing for combatting mould long term is keeping the house warm and humidity down, a dehumidifier will work wonders in the long term.

What temperature kills house mold?

Boiling water can kill mold outright (more on this in the next section), but you can't exactly boil your walls or carpet. However, you may be able to kill mold by heating it enough to dry it out. Most molds can be killed at temperatures of 140 to 160 degrees Fahrenheit, but the effect isn't immediate.

At what indoor temperature does mold grow?

Many fungi grow well at temperatures between 60 and 80 degrees Fahrenheit, which are also ideal temperatures for human comfort. In addition, as mentioned above, temperature gradients often produce the moisture needed for mold growth.

What temperature should I AC be to prevent mold?

The optimal temperature to discourage mold growth is around 77-78 degrees Fahrenheit. At this temperature, your AC will effectively remove moisture from the air, which is a key factor in mold prevention.

What is the ideal temperature for your home? The Answer Might Surprise You!

Does leaving AC on prevent mold?

Your AC can control the temperature and humidity in your home, which can prevent mold growth. During the hot, humid summers, set your air conditioner between 68 and 72 degrees Fahrenheit. The relative humidity in your house should not exceed 50%.

Is 72 a good AC temperature?

This is more of a personal question, as different people feel comfortable at different temperatures. Since 72 degrees is generally agreed upon to be an ideal indoor temperature, most people would probably still feel comfortable setting their AC units slightly higher than this, perhaps at around 75.

What is the best room temperature to prevent mold?

Keeping the air conditioner set at 78 degrees or lower prevents mold buildup in the summer. Even when leaving for a few days or vacation, don't set it above 80. A higher setting won't provide enough dehumidification from the cooling process to prevent spores from growing.

Is 33 humidity too low?

If the humidity is over 60 percent, then the air is considered to have a high relative humidity level. If the humidity is under 40 percent, then the air is considered to have a low relative humidity level.

How to stop mold in a house?

How to reduce condensation
  1. pull wardrobes and furniture away from walls, and keep tops of wardrobes clear, to allow air to circulate.
  2. close doors and open windows when cooking.
  3. keep lids on saucepans when cooking.
  4. keep bathroom doors closed when bathing, and open windows slightly afterwards.

Does a cold house make mold worse?

Cold rooms especially are often rarely visited by homeowners, but contain a damp, dark and cold environment that allow mold to flourish. Many people only consider mold growth following a water leak or flooding, but mold can grow anywhere, anytime in areas of your home that are damp and cold.

What dissolves mold?

Chemical or Natural Mold Cleaners
  • Use undiluted white vinegar on hard surfaces in kitchens and baths. Apply it directly to the mold.
  • Make a bleach solution to kill mold. Mix one cup of bleach in a gallon of water. ...
  • Mix a 50/50 solution of ammonia and water. Spray on the surface.

What temperature wash kills mold?

Choose the hottest setting on your washing machine. Most mold spores will die at temperatures above 140 degrees Fahrenheit (60 degrees Celsius), so cold and warm water cycles won't work. Add laundry detergent (regular detergent is fine). Add any other disinfectants, like vinegar, bleach or baking soda.

What are the 10 warning signs of mold toxicity?

Although symptoms can vary, the most common symptoms seen in people exposed to mold indoors include:
  • Nasal and sinus congestion.
  • Eye irritation, such as itchy, red, watery eyes.
  • Wheezing and difficulty breathing.
  • Cough.
  • Throat irritation.
  • Skin irritation, such as a rash.
  • Headache.

What is the lowest safe temperature for a house?

While away on long periods of time, such as vacation, we don't recommend setting the temperature any lower than 50 degrees (F). One of the last things you want is to come back home and find busted pipes and water damage throughout your home. This can be the outcome if the pipes freeze and burst.

What does mold hate?

Mold hates light. Other than moisture there's nothing mold loves more than dark places. An easy prevention against mold growth is opening your blinds and shades. If it's warm enough out, open the windows.

What humidity is best for sleeping?

Best Humidity for Sleeping

The best relative humidity for sleeping and other indoor activities has been debated. According to the Environmental Protection Agency, the best indoor relative humidity falls between 30% and 50%, and it should never exceed 60%. Other studies suggest 40% to 60% is a better range.

Can mold grow in 30% humidity?

Mold needs 55% or higher humidity in order to grow. Also, remember that reducing humidity below 30% isn't a good idea, either. This can cause health problems, making your eyes nose and skin dry, and exasperate lung and skin conditions.

How to dehumidify a room?

How to Dehumidify A Room
  1. Open your windows and doors. One of the simplest and most effective ways to reduce indoor humidity is by opening your doors and windows to improve air circulation. ...
  2. Turn on your fans. ...
  3. Run a dehumidifier. ...
  4. Use your air conditioner. ...
  5. Create a DIY dehumidifier. ...
  6. Combine the above methods.

What temperature kills mold on walls?

Now that we understand what mold is and the conditions in which it thrives, let's delve into the question: Does heat kill mold? The simple answer is yes. High temperatures (around 140 to 160° Fahrenheit) can deactivate mold spores and prevent them from spreading.

Does running a fan help prevent mold?

Ventilation fans are the best way to prevent mold build up inside a home. Think about it: what happens when a home has a flood? Typically, a water damage expert will be called in and the first thing they do is bring in ventilation fans to dry out the moisture and wetness inside the home.

Does leaving AC off cause mold?

How does keeping my AC running prevent mold and pests? Air conditioners help reduce indoor humidity levels, which can create ideal conditions for mold growth and pest infestations. Running your AC at a slightly higher temperature while you're away can maintain lower humidity and prevent these issues.

What temperature to set a thermostat to prevent mold?

If your home is susceptible to mold growth, set the thermostat at 72 degrees. While the best AC temperature to prevent mold growth is between 68 and 72 degrees, keeping it at the upper end of the range will give you mold-inhibiting results without the high price tag.

How cool should my house be if it's 110 outside?

For many of us, 70 degrees is the ideal indoor temperature, but when it is close to 100 degrees outside, your AC unit will be working quite hard to meet these expectations. Consider setting your thermostat at 75 degrees to 80 degrees in your home if the outside temperature is approaching triple digits.

Is 78 too hot to sleep?

For most people, 75 degrees is too hot to sleep, per the National Sleep Foundation. But the new study found that in people 65 and up, sleep efficiency only started to decrease when temperatures were above 77 degrees.

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