For heating efficiency nothing quite warms you as quickly as a gas space heater or central heater. You have a choice to use either convection type heat which provides warm surrounding air similar to a whole house heat where insulated walls and spaces are available, or Infrared Heat which primarily heats objects similar to the sun. Three (3) types of heaters are used: Vent free heaters which are 99% efficient do not require a vent and are normally mounted on a wall or set on the floor / Vented models use room air for combustion and vent typically through the roof, and finally Direct Vent heaters which use combustion air from the outside and vent the gas through the same vent system to the exterior. They are typically about 80% efficient and can heat an entire house with no loss of inside air to the flue system. Differences between gas heat and electric Heat Pump models can be felt by both the temperature being emitted from the heater and to the area being served. Gas heaters are much quicker to heat an area than electric units. You can even use gas models outdoors to heat an non-insulated patio area or garage.