Lots of old ideas about how heat pumps work. Technology is so much more advanced these days. The heat pump constantly measures your environment inside and out to give you the best outcome by varying it’s compressor speed to suit the environment and maintain the set temp. At Napier Heat Pumps. Our advice is to run the heat pumps when you are home. Running constantly lessons the life span of the heat pump. Heat pumps should last about 25000 hrs or approx. 15 years. Using a timer to switch on before getting up in the morning and switching off before leaving for work will help save power and run time.