6.3.1 Identify the various types of space heating equipment and range of efficiencies
- Gas and oil fired forced-air furnaces SS 60-86%,
Gas furnace - natural draft. Note the large exhaust pipe 
oil furnace with flame retention head - Induced draft gas SS up to 85%
induced draft can also be direct vent, you need to look inside to see where the fan is, on top is induced draft. - Condensing (gas) AFUE 90-98%,
condensing furnace has a condensate drain and direct venting for both in and out take. - Gas and oil fired radiant or hydronic boiler systems AFUE 82%-95%
boilers are connected to pipes and pumps for distribution - Electric forced air, radiant and convector 100%,
no venting with an electric furnace 
- Air source heat pumps HSPF 6-13
ductless mini-split systems have an external and internal delivery system 
ASHP can be connected directly to the furnace as an air handler for distribution - Ground Source Heat pumps COP 3-5 closed loop, can be much higher with open loop
GSHPs are connected to loops in the ground for heat exchange - Combi hot water/heating systems (condensing) AFUE 90-98%
combi systems can be heated at the boiler side with an air handler or at the furnace side with a heat exchanger distributing heat through a water medium to the second application - Wood or pellet: 45-80%
pellet stove with hopper built in - Gas space heaters, integrated mechanical systems variable efficiencies, oil fired combination systems…etc
