It uses the surrounding air that is the air inside your attic or crawlspace for combustion.
High efficiency furnace makeup air.
According to the u s.
However the overall efficiency of the house is.
In high efficiency furnaces the combustion air is generally piped in directly from the outside straight into the combustion chamber.
If your furnace lives inside a sealed attic or crawlspace high efficiency furnaces use a design that s well suited for those kinds of spaces.
This creates a dedicated source of oxygen and also a cleaner install as no other provisions need to be make for combustion air.
Very few people realize that a certain volume of air is required for proper combustion of the furnace and gas water heater for that matter and not many contractors pay attention to this simple code requirement.
Due to high efficiency furnaceshaving their own fresh air intake no air is drawn from inside your home.
The efficiency of a 90 afue condensing furnace is not affected by obtaining the combustion air needed from the outside of the house.
Different classes of filters are available depending on your needs.
A standard efficiency furnace provides 80 annual fuel utilization efficiency afue.
These days 95 afue is a common rating among new gas powered furnaces.
To get a sense of what this design entails first consider an 80 furnace.
Most condensing furnaces and some conventional furnaces use high efficiency air filtration media to improve indoor air quality.
72 000 btu 95 afue natural liquid propane gas mobile home forced hot air down flow furnace today you ll find our high efficiency gas today you ll find our high efficiency gas furnaces in more manufactured homes than ever before.
Bringing in fresh air for the entire house through the return air ducting on the furnace may help prevent a common problem when people upgrade their old heating appliances to high efficiency units.
High efficiency furnaces offer 90 or more afue.
In this type of furnace 20 of the energy produced by natural gas is expelled as exhaust.
These filters need to be changed regularly in order to work effectively.