Higher efficiency can be gained in a gas furnace with an alternative to the traditional pilot light such as an intermittent direct spark or hot surface ignition.
Ducted attic gas furnace make more efficient.
So a 95 furnace is more efficient than an 80.
High efficiency furnaces aren t usually recommended for an attic.
Assuming that the alternative to mini splits would be an 95 gas furnace with r 8 ducts in the attic and gas is 1 25 per btu it looks to me like i would need at least an 11 hspf heat pump if electricity rates are going to be 20 per kwh.
A furnace can suffer from a drop in energy efficiency if it s in an unconditioned space such as an attic.
In it the authors argue that attic ducts kill home efficiency they say that studies show a 20 percent energy use increase for homes with attic ducted units.
A standard efficiency furnace provides 80 annual fuel utilization efficiency afue.
That air is replaced by cold outside air that will then need to be heated.
Check replace your furnace filter.
If turning on your furnace makes you cringe in anticipation of high energy bills use these five steps to help you save money and increase your furnace efficiency.
It is much more efficient to use outside air for combustion air.
Hvac system problems can go undetected.
This process is the only way that you can create a thermal envelope that can provide a comfortable indoor environment throughout the year.
High efficiency furnaces offer 90 or more afue.
The trick to the installation of a gas furnace in an attic space is routing the condensate drain from the attic down through the core of the house to the basement.
If your furnace draws combustion air from inside the house you are using air that you have already heated.
Leaky seals in unconditioned vented attics can effectively turn an efficient 15 seer unit into a 12 meaning it s much less efficient.
These days 95 afue is a common rating among new gas powered furnaces.
5 steps to improving your furnace efficiency.
There is a common misconception that this is not possible for high efficiency furnaces.
As we get deeper into winter the cold weather means an increased use of your furnace.
There are rarely instances when we will advise against an attic installation.
Most of the issues that furnace might experience in an attic are due to extremely cold weather in this poorly insulated space.
90 of the attic would get the insulation benefits of the spray foam and then there s other options to help with the new furnace closet in the attic.
In this type of furnace 20 of the energy produced by natural gas is expelled as exhaust.
Ideally i would want higher because i know that hspf usually drops as temperature drops.