Everyone should get a professional home inspection when buying a home in Hawaii. But the inspector won't catch everything. Here are a few things that I've found can be missed.
1 - Sprinkler system. I don't know about other states, but in Hawaii the inspectors don't want to touch the sprinkler systems. They say they don't want to mess up the timing and kill the landscaping. But if they don't check it, who will?
2 - Slow plumbing leaks. This is really hard because they are slow by definition. Just last month a client of mine bought a condo at the Colony in the Peninsula at Hawaii Kai, and after she moved in she found that the leak the seller had repaired in the kitchen plumbing was still there, it was just slower. The only way to really check this is the run a lot of water for a long time, like 20 minutes, and put a paper towel under the sink. I realize this wastes water. Bummer.
3 - Non working outlets. I have seen an inspector check every single outlet in a house. Some of the bigger houses, like in Portlock, have hundreds of outlets. How can you check them all? You can get a little tester and stick it in the holes, but I doubt you'll do it.
4 - Old dying breakers. In older houses, the breakers tend to wear out and get to the point of needing replacement. I bought a home in Aina Haina and after we moved in we found that some of the breakers kept tripping once a day or so. As soon as we replaced them, it was no problem, but they cost about $50 each.
5 - Roof leaks, cracks, etc. Unless you are looking at your house in heavy rain, there isn't a way to be 100% sure about leaks. One thing you should do is look carefully at the ceilng everywhere. Do you see stains? Oahu gets a lot of rain, so if there is a leak you should see some stains. You can get a moisture meter to check and see if there is current activity. Sometimes there will be old stains from a leak that has already been repaired.
6 - Pool problems. The pool is always a mystery. Is it cleaning adequately? Is there a leak anywhere? Does the pump work ok? Is the heater functioning? I think the only thing you can do is talk to the owner and the pool guy. Ask the owner for their pool man's number and find our how the system is doing, what it's costing for maintenance, and if there are any upcoming repairs needed.
7 - Rain Gutter flow. If it's not raining, you can stick a hose in the gutters and see how they work. I had a buyer do this once. It was kind of annoying, but once he started doing it, I could see the point. The gutters were backed up in the places you couldn't see into.
8 - Problem neighbors (especially in a condo). You should meet the neighbors where you want to live. No matter how nice your new home in Mauna Lani heights is, if you have bad neighbors, you're going to hate it there. Even in a nice neighborhood like Kahala, you could have neighbors that turn out to be a problem for you. What if you have a problem with a dog or a fence on your boundary? Before you move in, meet the neighbors and ask them how they like it.
9 - AC unit condition. Even if the AC blows cold, you don't know how the system is. Are there any leaks? Is it low on freon? Maybe it's working well now but not in a month. Try running it full blast for an hour or more while you check the other things on this list. If it drips water into the house, you're in trouble.
10 - Insulation. Recently a buyer of mine purchased a home in Mililani Mauka and we found the insulation had been installed upside down. So it wasn't doing anything! No wonder the house was feeling so warm! You should ask the seller which walls are insulated and how hot the house gets. Feel the ceiling, is it hot to the touch? It should be cool. If not, it's not insulated!