The Hidden Flaw in Some High-Efficiency Furnaces

Prime: 
prime

Subtitle: 
Hint: Furnaces use two forms of energy

Images: 

You can tell how energy-efficient a furnace is by its official efficiency rating, the Annual Fuel Utilization Efficiency(AFUE) Widely-used measure of the fuel efficiency of a heating system that accounts for start-up, cool-down, and other operating losses that occur during real-life operation. AFUE is always lower than combustion efficiency. Furnaces sold in the United States must have a minimum AFUE of 78%. High ratings indicate more efficient equipment.
(AFUEAnnual Fuel Utilization Efficiency. Widely-used measure of the fuel efficiency of a heating system that accounts for start-up, cool-down, and other operating losses that occur during real-life operation. AFUE is always lower than combustion efficiency. Furnaces sold in the United States must have a minimum AFUE of 78%. High ratings indicate more efficient equipment.
). It’s a measure of how much of the heat originally in the fuel that’s being burned is available for delivery to the home. The more heat that gets lost up the flue or through the cabinet, the lower the AFUE.

But that rating doesn’t capture all the ways a furnace can lose efficiency. Some, like how well the heat gets distributed to the house, aren’t related to the furnace itself. But there’s one big one that is related to the furnace.

read more

The Hidden Flaw in Some High-Efficiency Furnaces

Prime: 
prime

Subtitle: 
Hint: Furnaces use two forms of energy

Images: 

You can tell how energy-efficient a furnace is by its official efficiency rating, the Annual Fuel Utilization Efficiency(AFUE) Widely-used measure of the fuel efficiency of a heating system that accounts for start-up, cool-down, and other operating losses that occur during real-life operation. AFUE is always lower than combustion efficiency. Furnaces sold in the United States must have a minimum AFUE of 78%. High ratings indicate more efficient equipment.
(AFUEAnnual Fuel Utilization Efficiency. Widely-used measure of the fuel efficiency of a heating system that accounts for start-up, cool-down, and other operating losses that occur during real-life operation. AFUE is always lower than combustion efficiency. Furnaces sold in the United States must have a minimum AFUE of 78%. High ratings indicate more efficient equipment.
). It’s a measure of how much of the heat originally in the fuel that’s being burned is available for delivery to the home. The more heat that gets lost up the flue or through the cabinet, the lower the AFUE.

But that rating doesn’t capture all the ways a furnace can lose efficiency. Some, like how well the heat gets distributed to the house, aren’t related to the furnace itself. But there’s one big one that is related to the furnace.

read more

Manual J Doesn’t Tell You Equipment Capacity

Prime: 
prime

Subtitle: 
The amount of heating and cooling your house needs isn’t the only factor in determining the size of your heating and cooling equipment

Images: 

Here’s a little conundrum for you. To get the right amount of heating and cooling to each room in your home, you need a load calculation. Rules of thumb don’t work. But if you do a load calculation, the result isn’t the size of air conditioner, heat pumpHeating and cooling system in which specialized refrigerant fluid in a sealed system is alternately evaporated and condensed, changing its state from liquid to vapor by altering its pressure; this phase change allows heat to be transferred into or out of the house. See air-source heat pump and ground-source heat pump., furnace, or boiler you need. It’s only the first step to sizing your system.

Do you know why? Let’s take a look.

read more

Manual J Doesn’t Tell You Equipment Capacity

Prime: 
prime

Subtitle: 
The amount of heating and cooling your house needs isn’t the only factor in determining the size of your heating and cooling equipment

Images: 

Here’s a little conundrum for you. To get the right amount of heating and cooling to each room in your home, you need a load calculation. Rules of thumb don’t work. But if you do a load calculation, the result isn’t the size of air conditioner, heat pumpHeating and cooling system in which specialized refrigerant fluid in a sealed system is alternately evaporated and condensed, changing its state from liquid to vapor by altering its pressure; this phase change allows heat to be transferred into or out of the house. See air-source heat pump and ground-source heat pump., furnace, or boiler you need. It’s only the first step to sizing your system.

Do you know why? Let’s take a look.

read more