The answer to 'heat pump blowing hot air' is that your heat pump is likely in cooling mode instead of heating mode. This can happen if the thermostat is set incorrectly or if there is a problem with the heat pump's reversing valve that controls the direction of refrigerant flow.
Some common causes include a faulty thermostat, a stuck or malfunctioning reversing valve, low refrigerant levels, or issues with the compressor or other internal components. Symptoms may include the heat pump blowing warm or hot air when you expect it to be heating your home.