# Efficiency of my new HVAC system?

#### dhar2112

##### New member
Hello and thanks for taking the time to read.

Just installed a new furnace and A/C and Feb. was our first full month of it being in use. What I'm trying to figure out is how much less electricity we used over last Feb. considering this Feb. was colder:

This Feb. we used 23% less electricity than last Feb.

This Feb. was 29% colder than less Feb.

So I guess I'm wanting to know if this Feb. and last Feb. had the exact same avg. temp., then the "23% less electricity used" would really be?

#### dhar2112

##### New member
Thanks

and yes, I just wanted an idea of what my TRUE efficiency is, so perfect answer.

#### stapel

##### Super Moderator
Staff member
Just installed a new furnace and A/C and Feb. was our first full month of it being in use. What I'm trying to figure out is how much less electricity we used over last Feb. considering this Feb. was colder:

This Feb. we used 23% less electricity than last Feb.

This Feb. was 29% colder than less Feb.
How are you counting the "29% colder"?

So I guess I'm wanting to know if this Feb. and last Feb. had the exact same avg. temp., then the "23% less electricity used" would really be?
..."would really be" what? Also, in which hemisphere is this measuring going on?

Note: If the new A/C used exactly the same amount of electricity under the same circumstances, then the new A/C would arguably not be "more efficient" (assuming efficiency is measured in terms only of power usage). What equation were you given for the "efficiency" computations? Thank you!