It is best to avoid placing a piano next to a heating source or in the sun. Inside walls without baseboard heaters are best. Don't have a wood stove or an active fireplace in the same room with the piano if you can help it.
Dry finished basements with dehumidification in the summer are OK for a piano. Damp basements will destroy a piano. The strings will rust and the veneer will come off. Also the glue around the soundboard may break loose.
Try to maintain a constant humidity in the piano room. A cold room won't hurt a piano in the winter. It is better than an overheated room where the relative humidity may get in the single digits, particularly with a wood stove.
Cleaning a piano should usually be limited to dusting and vacuuming. The finish can be waxed with a good quality cream furniture polish. The one I prefer is Oz polish. Do not spray aerosol sprays directly on a piano. Some contain alcohols or other solvents that may spot the finish.
Do not spray the tuning pins on a grand piano with any cleaners or waxes. They may get down into the pin block and loosen the tuning pins.
Never use any kind of cleaner or polish on the bass strings. It will get between the windings and prevent them from vibrating, resulting in dull sounding strings.
To clean keys, you can use dilute rubbing alcohol that is 50% alcohol. You can also use a cream furniture polish and elbow grease. Some spray cleaners can be used- but don't spray the keys directly. Put a little on a cloth and wipe the keys with the cloth. If black paint comes off on your cloth from the black keys-stop. The cleaner is too strong.
Soundboards on grands can be vacuumed with a shop vac if you can loosen the dust first with a long bristle brush. A 4 inch wide nylon painter's brush with long bristles can be worked through the strings to stir up the dust on the soundboard so the vacuum can pick it up. You can do the same between the tuning pins. The brush won't be much good for painting after that. The bristles will get bent.
Moving and placing a piano
To protect hardwood floors when moving a piano even a little bit, put down thin plywood or masonite to roll the piano on. Otherwise, you may make grooves in your floor because of the piano's weight on the iron casters. Pine floors are even worse.
Place caster cups under the casters to protect your floor and carpets. Many casters are iron and will rust and leave spots. Use hard rubber, wood, or metal caster cups with felt or carpet on the bottom.
Wheels on piano legs are mostly decorative.- not for moving a piano. Spinet and console legs are too thin and easily broken and should be removed from the piano when it is moved.
Baby grand legs can withstand a little moving but care should be taken if the floor is uneven or carpeted. It is best to have several people lift a baby grand slightly when moving it, or the legs may break. If moved more than 10 feet, have a piano mover put it on edge on a skid and dolly to move it. Call me before risking damage to the legs on your piano.
If you live near the salt water, keep your piano away from open doors and windows. The salt air will corrode the strings and shorten the life of the dampers. I recommend putting a rust inhibitor inside the piano if you are near the water or have a damp environment. That includes any house on Long Island without central air conditioning. I have small blocks that will prevent further rusting for up to two years in a closed piano. Call me for one.
NEVER, EVER put a potted plant, vase of flowers with water or container of ice or water on a piano. The moisture can ruin the finish. I can fix it but it is better to avoid the problem.
Don't use a piano as a bar. Drinks get spilled and it is very hard to clean them out of a baby grand. Call me soon if it happens. I have been successful at removing these spots.
Smoking around a piano will eventually leave a coating of tar and nicotine on the entire piano. This is particularly bad for the bass strings which will get very dull sounding.
Don't install a fire sprinkler system over a piano. They sometimes leak or go off spontaneously. The water will ruin the piano. I would rather rebuild a piano that has been in a fire than one that has been drenched.