These pages were written to make things a little more convenient doing HVAC work.
Hopefully you can get some use out of these calculators.
1 - Whole house Manual-J load calculator
2 - HVAC Helper is a diagnostic aid to help with trouble shooting specific problems.
3 - Psychrometric calculator calculates properties of air and total system btu's.
4 - Superheat calculator gives design superheat from outdoor and indoor conditions
5 - Capacitor calculator explains and give results for capacitors in series. It also explains a little about multi-speed motors and estimates proper amp draw for each speed.
6 - CFM calculator shows CFM using temperature rise or velocity formulas
7- Defrost sensor shows the resistance for temperature ratings