One cubic foot of natural gas contains about _____ of energy:

In ________ the cooler air is drawn at the base of the furnace, and the warm air exits out the top of the furnace:

These older natural gas systems usually have seasonal efficiencies of about ______ :

The optimum excess air required for the complete combustion of natural gas fuel burners will be approximately:

For radiant floor heat, hot water temperature can be much higher than for space heating:

Boilers that meet or exceed an _______ efficiency rating are labelled as Energy Star compliant:

Efficiency of the boiler is inversely proportional to the number of passes:

Heat pumps with the highest SEERs and HSPFs invariably use variable or two-speed ______ compressors:

In heat pump, a _____ absorbs heat from the outdoor air and transfers it to indoor:

_______ is the measurement of the actual amount of available energy that transfers into the heating medium:

Convective heating should be used in draughty rooms, rooms with high ceilings or areas with open stairwells:

Replacing the conventional burner with a flame retention head burner will save _____ on the fuel:

Fire tube boilers, systems are simple and easy to construct and are generally used in low-pressure applications:

Antifreeze ______ solution is specially formulated for hot water heating systems

In Quartz lamp heating, the elements of this type of heater operate at about _______ and consist of a tungsten wire coil sealed within a quartz tube