temperture

[flajoker]

What is the standard for temp. difference between supply and return air?
How good can it be?

[billva]

heating or cooling?

cooling 15-20 deg.

heating, whatever the data plate states for a heat rise, shoot for the middle of that range.

if a heat pump as opposed to fossil fuel, then, as a "rule of thumb" which doesn't mean much, in the heat mode without any aux heat running, at 32 deg o.a., the split should be around 20 deg. for every 3 deg. higher, add 1 deg of split temps.

i.e. 35*=21 split.
29*=19 split.

this is not a perfect example, but only a reference.

good luck

[gordondemarko]

a good temp. is 15 to 20. Why because if it goes to 25 to 30 the evap. coils will start to get frozen.

[beenthere]

Is your heat pump, in the heat or cool mode?
In heat it will vary by the ouotdoor temp.