Old wall heaters are similar to space heaters, but are installed permanently in a wall and are often gas powered. Wall-mounted gas heaters require cleaning just as any other household appliance to operate safely and efficiently. A thorough cleaning is especially important if it has been a long time since you used the old wall heater; a thick accumulation of dust is probably present on the inner coils.
Turn off the wall heater. Wait at least one hour until the entire heater has cooled to room temperature.
Locate the main breaker panel for the home where the fuses are located. Turn off the breaker switch for the wall heater so no power is supplied. Locate the gas shut off valve, which is typically behind the wall in a panel or under the house. Turn the knob or lever to shut off the gas.
Remove the outer grill or grate on the wall-mounted heater, according to the manufacturer's instructions. You must typically remove four or more screws from the edges of the grill using a screwdriver. If necessary, pull the knob of the heat control dial off before detaching the grill.
Take the grill to a sink. Dampen a sponge with warm water and wipe the entire front and back of the grill to remove all dust from it. Dry the grill well with a lint-free cloth to remove all water droplets.
Go back to the wall heater and plug in a vacuum cleaner. Insert a brush attachment onto the end of the vacuum hose and turn the vacuum on. Gently vacuum all interior portions of the wall heater to remove the dust.
Place the grill back in place and re-insert the screws using a screwdriver. Turn the electricity and gas back on for the wall heater.