If you're going to convert your garage into a bedroom, you'll need to figure out how to control the climate in the space. A ductless heat pump could be the best solution. It is easy to install, and it eliminates the need to put a strain on your current central heating system. Here is some more information on how a ductless heat pump works.
Provides Complete Climate Control
When you install a heat pump in your new room, you'll be able to control the climate in the room regardless of the temperature in the rest of the house. This ensures you'll stay warm when sleeping at night, which is important if the new room will be used as a kids' bedroom. The blower is mounted high on the wall, so it is out of the way and out of reach of kids. You operate the fan and temperature settings with a remote control, so you stay comfortable as the temperature outdoors changes. You can buy a heating-only system or one that includes refrigerant for air conditioning in the summer.
A ductless heat pump works in a similar way as a window air conditioner that blows heated air as well as chilled air. The difference is a ductless system is more efficient and safer because a window doesn't have to be open in order to use it. The fan is mounted directly on the wall, and the only access to the outside is a small hole that's large enough for cables to pass through.
One of the reasons a heat-pump system is so efficient is because there are no ducts that allow heat loss. Instead, the power unit that sits outside the house is connected directly to the fan that is inside. Cables connect the two units through a hole in an exterior wall of your home. This saves on the need to install duct work to integrate the new room into the heating system of your home. Ducts are eliminated, and even more importantly, the temperature will be better controlled with a dedicated heat pump. The garage is typically set off the kitchen, so heat from the house will have a hard time circulating through it.
The only options for keeping the space warm is to add ducts to your current system—and this may strain the system to the point where no room in your home is completely comfortable—or adding an independent heating system. Space heaters are not safe, especially for kids' rooms. Installing a ductless heat pump is the ideal solution, and an added bonus is the savings on your power bill due to the energy efficiency of these systems. Just be sure to buy one that is Energy-Star rated so you know what you're buying when it comes to energy consumption and operating expenses.