90% Furnace venting. Posted on August 22, 2012 by Andy. With these higher efficiency furnaces, came some other considerations. The 90% implies that 90% of the heat that is put into the furnace is transferred into the duct system and subsequently into the homes living space leaving only 10% going out the exhaust.
The definition of a direct primary election is when people vote for candidates of their political party by direct vote instead of by delegates at a convention.
Video: Primary Election Versus General Election: Definition & Differences. In the United States, we use two different types of presidential elections. Both primary and general elections are used to determine a winning candidate. This lesson explains primary and general elections, including the differences between the two.