The field of energy efficient heating systems is advancing rapidly and constantly and I cannot evaluate all the new products here. Remember that it usually takes a company a couple of years to work the bugs out of new products. And some companies try so hard just for novelty that... for example in the early 80's someone in Regina was selling a thing called the Friction Furnace. It was a device that that heats up a barrel of oil by spinning another barrel inside it driven by an electric motor: the friction heat given off heats the house. It struck me as using a lot of moving parts to accomplish no more than a resistance heater could do easier embedded inside that same barrel of oil. But moving parts do impresses some people.
Here are some better alternatives:
-- A new addition to this list in 2013 -- the Tri-Energy system where Dual Energy hydro rate systems are improved with a staged plenum heater and a full system controller to produce results that match that of a geothermal system, without the up front costs.
-- Extremely efficient gas furnaces have come onto the market -- some so efficient that they require only a small plastic pipe for a chimney and a drain for the flue condensation, as there is almost no heat wasted. These devices have come fully of age and are now quite reliable. Expensive up front, but worth it in an era or rising gas costs. Starting in 2010 in Canada all gas furnaces will be required to rate 90% or higher in efficiency, essentially making condensing furnaces a requirement.
-- Air-tight wood furnaces are efficient, but you have to be prepared to haul wood and tend the fore. Some operate on automatically-fed wood pellets. The efficiency of solid fuel burning appliances at the turn of the year 2000 are remarkable compared to what we had 10 years ago.
-- Efficient gas fireplaces are rapidly replacing wood fireplaces, even efficient wood stoves. They are cleaner and easier to use, very efficient and look quite classy.
-- Electrical heaters convert almost 100 per cent of the electrical input into heat. But, where the electricity is generated by oil they are in fact less efficient than oil furnaces -- if you are looking at the question from a point of view of national resources, or projected electrical rate hikes. Hydroelectric supply can be the cheapest fuel available, such as in Quebec.
-- Electrical plenum heaters can be used in combination with air-to-air heat exchangers as a complete heating system, providing the house is well enough insulated to have a January design-load requirement of not more than 20 kW.
-- Ground source or water source heat pumps can operate without a furnace back-up because of the reliability of the underground water heat source. You can find information on Solar systems and heat pumps through the keyword search.
-- Gas, Oil and Electrical furnace and boilers are now commonly made in the much smaller sizes that small energy efficient houses need. In the early 80's we were using heaters designed for mobile homes because we couldn't find anything else small enough.
-- Combo systems are around the corner in the near future -- single units that take care of household ventilation, heat recuperation, space heating and sometimes even domestic hot water heating. The concept is to bring all these things together into one unit that can accomplish all of that more efficiently than having separate operations for each function.