At the time the furnace was purchased, Attic was only 2 inches loose
insulation,
full basement non-insulated. No heatload calc was done. they had this
table they
use. I figured should be similar to
http://www.saskenergy.com/residentia...naceSizing.pdf
Previous 'dinosaur furnace was 100KBTU'.

The NEW furnace installed is Rheem 80% 2 stage: model RGPK-O7EAMER

As per sticker on the furnace:
rated 1st stage: 52500BTU
2nd stage : 75000 BTU
House is typical box with roof (barn type?)
1140 sqft area.

After a year, I had added insulation to the attic
(added R12 bats 3 layers). Also insulated the basement walls to R14
Roxul,
sealed the sills tried to eliminate air drafts. I havent touched the
old windows
yet. Just used clear plastic to minimize draft.

This winter found out that running the furnace in 1st stage only, the
furnace is able
to maintain temperature. It appears like I don't need the
2nd stage. The temperature does not dip even at coldest outside.
The 1st stage do run much longer before it stops when temperature
is met.

I guess my question is, do I have an oversized furnace?

Thanks,

Gerry