alt Hacker NewsPutting semiconductors in front of a 3+ ton heat pump when you live in a rural area is guaranteed bad times.
Not only can you not find many people who have parts or knowledge on hand, but you also have to deal with the fragility of the system. A single stage compressor is very robust to electrical transients. These units can take direct lightning strikes and continue to function normally. Worst case, you replace a contactor, capacitor and some wire. Every hvac tech on earth has these things in their truck right now.
Efficiency and gently ramping loads are nice, but these things don't matter so much if the system is going to have maintenance issues.
the factors that kill semiconductor switches are heat and voltage switching transients. This is why the 800 V electronic components in some EVs fail - the voltage.
The voltage in a heat pump is 240 V. The power is typically a couple of kilowatts. Reliability of silicon switches at that voltage is excellent. This is just not a widespread problem.