On Fri, 7 Apr 2017 08:44:25 -0700 (PDT), TimR
wrote:

On Friday, April 7, 2017 at 8:55:23 AM UTC-4, TimR wrote:
On Wednesday, April 5, 2017 at 5:11:07 PM UTC-4, wrote:
I just ran a basic whole house manual J on my 2 story house with
finished basement in Waterloo. I was conservative - going for the low


Ding ding ding! We have a winner. Without a manual J you are just guessing. Install companies always estimate too high, and deliver oversized equipment, which is the worst thing in a humid climate.

If you've done a manual J, and you have a number for what your load is supposed to be, theoretically you could test it.

You could keep track of the run time of your equipment and the degree days, and see if you got it right.

I have never seen this done, in either residential or commercial. That is strange in commercial where you have DDC control and can track actual flows and heat transfer - maybe design engineers don't want to know.
I can monitor my run-time - and do on occaision as a sanity check.
My conclusion is my 35000BTU furnace (on low fire) is slightly
oversized 90% of the winter, and my AC is at least 50% oversized -
just about what the Manual J predicts. I had not run the manual J
untill the other day - and I knew both were oversized when I installed
them.

The furnace, as I noted previosly, was the smallest residential
furnace readilly available when I had it installed, and the AC was a
free unit I installed to replace a 35+ year old unit that was still
working. The free unit was only a couple years old when a neighbour
changed out both furnace and AC for some unknown reason.. I scrapped
mine instead of his. Mine was getting "a bit long in the tooth" and I
figured it would need replacing soon anyway.