Butane and gas heaters: avoiding damp and mould in winter
Portable butane heaters are common in Spanish homes but add moisture and need ventilation. How to heat safely, limit condensation and keep walls mould-free.
· 2 min read
Why a butane heater makes a room damper
Burning butane or propane produces heat, but also water vapour and carbon dioxide. A portable gas heater can release a noticeable amount of moisture into the room, and in a cool, closed space that moisture settles on the coldest surfaces: windows, outside walls, wardrobe backs and corners.
That is why many homes on the coast feel clammy in winter even when the heating is on. The damp is not always coming through the wall; sometimes we are adding it ourselves.
Heat safely first
Any appliance that burns gas needs fresh air. Follow the manufacturer's instructions, never use one in a sealed bedroom or bathroom, never sleep with it on, and keep curtains, clothes and bedding well away from it. Check the hose and regulator for cracks and the expiry date, and never leave a cylinder in a spot that gets very hot.
A carbon monoxide detector is inexpensive and worth having in any home that uses gas or a fireplace. If you are unsure about a heater's condition, have it checked by a qualified installer rather than guessing.
Limit the condensation
Open a window slightly for a few minutes on both sides of the home once or twice a day, even when it is cold outside. Fresh air exchanges the humid air for drier air, which is then easier and cheaper to warm. Keep furniture a hand's width from outside walls so air can move behind it.
If you can, consider an electric alternative such as an oil-filled radiator, an inverter air conditioner in heating mode or a heat pump, which do not release moisture in the room. A dehumidifier helps further, and wiping window condensation each morning stops it running down into frames and sills.
Cleaning mould that has already appeared
Small patches of surface mould on painted walls, window seals or silicone can be cleaned with a mould-specific product or diluted white vinegar, following the label, with the window open and gloves on. Never mix products, and dry the area afterwards. If mould returns quickly or covers a large area, the cause needs fixing, not just cleaning.
If you look after a second home or a rental, our regular visits include checking for early signs of damp and airing the property. We will tell you what we see so you can decide what to do next.
