How AC and Heat can affect your wooden furniture

Posted on 17 October 2025
By Michael Fournier
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This post details how humidity, heat and home air conditioning systems can affect wooden furniture and gives suggestions on how to care for furniture to prevent damage.

Home air conditioning and heating can damage wood furniture by causing it to expand and contract due to fluctuations in temperature and humidity, which can lead to cracking and splitting. Air conditioning and forced-air heating systems, in particular, can dry out the air, causing wood to lose moisture and shrink, while high heat can also cause fading and drying. To protect your furniture, maintain a consistent environment between 68 and 72 degrees Fahrenheit and a relative humidity of 35 to 40%.

How heating and cooling affect wood

Seasonal expansion and contraction:

As temperatures rise and fall, wood naturally absorbs and releases moisture, causing it to swell and shrink. This cycle can lead to cracks and splits over time.
Forced-air heating:

Winter heating systems are especially damaging because they dry out the air, which pulls moisture from the wood and can cause it to shrink and crack.
Air conditioning:

While air conditioning also reduces humidity, the damage is typically less severe than with heating systems, though prolonged exposure can still affect finishes.
Fading and drying:

Direct sunlight and heat from vents can cause wood finishes to fade, dry out, and crack.

How to protect your furniture

Maintain consistent conditions:

Aim for a stable indoor climate, ideally with a temperature between 68 and 72°F and a relative humidity between 35 and40%.
Use a humidifier in dry winter months and a dehumidifier during humid summer months.
Avoid direct heat sources:

Place furniture away from heating vents, radiators, and direct sunlight to prevent drying and fading.

Position furniture carefully:

Keep furniture a few inches away from walls and air vents to allow for proper air circulation around the pieces. Avoid placing furniture directly on floor vents.
Use protective measures:

Use curtains, blinds, or UV-protective film on windows to block direct sun. Consider using an air vent extender to redirect airflow away from furniture on the floor.
Regular maintenance:

Dust furniture regularly and apply wood polish or conditioner as recommended by the manufacturer to help maintain moisture levels in the wood.

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