Wall Heaters or Hot Air Curtains are a great cheap alternative to an air source heat pump.  The electric element inside the unit heats up and a fan inside the unit blows down into the room, circulating the warm air across the room.  They all will have a COP of ~1, meaning a 2Kw wall heater will use 2Kw of electric an hour, however there is no outdoor unit, no pipe runs, no refrigerant, just a simple heater element and a fan.  Making these wall heaters ideal for shops with no outside walls, terrace houses in conservation areas and high rise flats.

Air Curtain

Have you ever wondered why, when you walk into a shop you get a blast of hot air on top of your head?  This wall mounted heater is called an Air Curtain.  These air curtains are designed to blow air down around the sides of the doorway and infront of it, stopping any cold air from getting into the shop and keeping all of the warm air inside.  They will also stop any draughts inside the shop, help reduce the amount of insects and bugs that get into the shop and generally provide a nicer atmosphere inside the store.  They can also be used in homes as well, for example if you have a dog running in and out of the house all day long and are fed up of opening and closing the back door, an air curtaain placed above the back door will stop all of your heat escaping, saving you money on your energy bills.