Can I paint the plastic shell over my Daiken heat pump?

I wouldn't see why you couldn't. Just be sure and not get any paint on the inside workings. If the case is metal, use paint made for metal. If it's plastic you could use most any kind of exterior paint. Paint it a fun color!

I would check with the dealer who installed it for you. Depending on the unit, I would be concerned to do this without checking. If it is a newer unit, it may void any warranty you have on it. When I googled to find info to try to answer your question it showed a unit that had vents surrounding the inside workings. I believe it would be hard to paint it without overspray or paint running into the unit if you painted it with a brush. Personally, I would not take the chance with such an expensive piece of required equipment. Ask a professional who installs them--and rely on their experience.

Underneath the cover are very delicate fins typically made of aluminum. If you need to paint the cover, remove it from the unit and paint in an area far removed from the unit. If the fins get damaged, your heat pump won't be able to properly dissipate heat.

I would chesk with the supplier before doing anything!