There are both indoor and outdoor wood boilers and furnaces. Outdoor boilers are really big wood stoves with a tank of antifreeze solution or water surrounding them. The burning wood emits heat to the fluid, giving hot water and energy to warm the house. The boiler temperature is regulated by a home control system. Most include an alarm for re-stocking. Furnaces provide warm air; they come as indoor units only.

Once you have identified the air leakage points from an assessment of your home, you can proceed with the insulation process.  

Caulking

You should begin by sealing up small cracks, leakages and penetrations on the inside of the outside walls, floors and ceilings. The interior is usually warmer and applied sealant lasts longer as it is not exposed to harsh weather conditions.

The Energy Guide program was created to assist in the rating of "white goods", but what about smaller items and electronics which have no such label program?

There aren’t many people who would be content with a home that is not equipped with major electrical appliances, entertainment systems and computers. It isn’t wrong to have and enjoy a large-screen TV (unless you watch it the whole day!) or air conditioning. Using the energy to run the equipment is not the issue. The issue is purchasing inefficient models and, worse still, employing polluting and non-renewable resources to run them.