I’m getting vastly different results when trying to calculate BTU requirements for a single-room mini-split AC.
The AHM calculator is coming up with numbers around 15-16k. The This Old House calculator is coming up with approx 9600. Both of these calculators seem to be cloned across the internet. Meaning, I can tell that the calculator is either one or the other of these 2. Example, Consumer Union uses the same calculator as AHM.
What worries me is that I am reminded everywhere that too big is bad, and too small is bad. Also, from the reality perspective, my only choices are 9k, 12k, 18k.
Should I not worry and go with bigger, or split between the 2, or go with smaller, or ???
Thanks,
Martin
Replies
Or caclulate it yourself. Get a 'Manual J' from the library? A couple of potential problems w/ your calculators ... do they SPECIFICALLY account for your windows, orientation, and shading? Do they account for your wall construction and the age of your house? Did they also account for your specific location/climate. If they don't, they are generalizing. If you want to do it right to maximize comfort and efficiency, then you should do it long hand (i.e. detailed calcs accounting for all relevant aspects).
If you don't feel like doing the details, you might pick the 12K. The 9K MIGHT be too small based on your calculators. The 12 may cover many conditions ... except possibly extreme conditions ... which may occur only a handful of hours each year.
Also ... is this a space occupied all day? What is the orientation? Where are you located? This is all important information to properly choose your system if you want to do a good job. Pay your money and take your choice. Easy may not be the best choice comfort and efficiency wise.