You will get the right amount of ventilation in your bathroom if you choose the right size of the fan. You should search for CFMs, or cubic feet per minute, as it indicates the ability of a fan to move air. Small heaters can't generate a lot of CFMs and are perfect for small bathrooms. Respectively, larger fans that generate higher CFMs are better for larger bathrooms. The Home Ventilating Institute has published recommendations and guidelines that everyone can check in order to pick the right size. However, there is a simple rule that you should follow.

•  One square foot in the bathroom should have at least 1 CFM:  For example, if your bathroom is 50 square feet, get a heater with 50 CFMs to achieve the optimal ventilation. Bathrooms larger than 100 square feet should follow these recommendations: •  Add 50 CFMs for a toilet •  Add 50 CFMs for every shower plus bath combination

Portable fan heaters: Portable heaters are the lightest and can quickly heat up or cool down the room. They are also easy to operate - you just take it out of the box, plug in and this is it. However, cheap models can be noisy.

Convector portable fan heaters: These are very tall but also light and thin - it's easy to move them around. Like the previous type, they heat up quickly but they are less noisy. Convector portable fan heaters are wall-mountable, which means you can put them out of the way. Of course, you will find instructions in a box with a heater but you should be prepared to drill holes in the walls.

Oil-filled portable fan heaters: Oil-filled portable fan heaters are pretty slow to heat up but they are cheap to run. However, almost all models are heavy so look for those that have wheels as it makes easier to move them around.

Electric Wall Fan Heaters: Energy efficient, easy-to-install and safe, these heaters can be mounted into a wall. They are often located far from sinks and bathtubs and there is no risk of electrocution. Besides, they are also fairly cheap. If you have a small bathroom, this could be one of the best choices.

Infrared Fan Heaters: These heaters use infrared radiation, thus they are pretty cheap. They also help people who suffer Seasonal Affective Disorder during cold winter months. Bear in mind that you should keep these fan heaters away from the water.

Ceiling-mounted Fan Heaters: Ceiling-mounted Fan Heaters are perfect for homeowners who want a permanent fan heater - these heaters don't clutter the room. This type of fan heaters is pretty safe as it is mounted on the ceiling.

Floor Fan Heaters: Floor Fan Heaters are placed between special mesh mats under bathroom tiles. They prevent home owners from freezing off their toes on the bath floor again. They consume the same amount of electricity as a 300W light bulb, thus they don't add up to the electric bill. However, they are more expensive than others. People who want to renovate the bathroom and have a budget for it should consider this option.

Some fan heaters have advanced features such as the remote control for turning the device on and off from anywhere in the room or an LCD display that shows temperature. The most expensive models can also have a fan heater timer that is used to turn the heater on before you wake up or get back home so you don't have to wait for the heater to warm up. Many models also feature frost protection, which means that these heaters can work even when the temperature is below five degrees.

Climate control: With this feature, a fan heater will heat up or cool down the room and when the comfortable temperature is reached, the heater will remain this temperature in the room.

Noise Level: Some cheap models can sound like jet engines; these models will retract you from enjoying a relaxing escape that is your bathroom. As you search for a bath fan heater, you will always want to consider noise level and choose quiet models.  Bath fan heater sound is measured in sones.

A sone refers to a measure of sound as it related to how the sound is sensed by an average person. For example, one sone is like a quiet hum of a fridge in the kitchen at night. If you search for a quiet bath fan heater, choose a sone rating of two or one. Fans rated at four sones are noisier, while fans rate at five sones is not suitable for a bathroom.

Efficiency: Before you buy the heater, make sure that it meets qualifications for low wattage consumption, low sound emission, and have an efficient performance under static pressure. You can also get a model that has a motion sensor to help you make sure it works only when needed.

Unsurprisingly, bath fan heaters can get hot. However, if you read the instructions and use the heater accordingly, they are safe devices. Many models have a carry handle for moving them around, and they also have a safety cut out feature - you can switch off the heater if it gets hot. Never cover the heater up, never place anything on it, because it will increase the risk of fire. More expensive models also have a tilt protection feature - if the heater falls down it automatically switches off. This feature is necessary if you have a large dog or kids.

The design of bath fan heaters:  The cheapest heaters aren't the most fashionable devices, but some of the advanced models have a lot of colors and designs to choose from. Some of them have futuristic looks, others look modern or minimalistic to suit your bathroom.

How to position the bath fan heater:  In order to heat or cool down the bathroom, bath fan heaters need an inflow of air. Sometimes, more expensive models have inflow vents on the top or bottom. But if the model has a vent on the back (like the vast majority of the models), don't place it against the wall. Besides, oil-filled heaters should be placed in the middle of the room - when the room has a comfortable temperature, you can move it out of the way. Convector bath fan heaters can be placed anywhere.

Bath fan heaters can cost you as little as $15 for the cheapest model all the way up to $500 for more advanced models with many features. However, many manufacturers produce cheaper heaters - you will easily find a lot of models in the $15-$100 price range. More expensive models often have better designs and feature advanced safety. But you don't have to spend several hundreds to get a model that works efficiently and quietly. According to bath fan heater tests, there are models that cost $60 that can beat more expensive models.

Before choosing a bath fan heater, you should make sure you will get the one that is adequate for the size of the room. You will also want to consider your needs and wants with regard to features and noise level so that you will get the most for your budget.