There are 2 fundamental parts to having an efficient PoH:
1) The layout
and
2) The loading time
Layout
The optimal layout is 3×3 if you have the required construction level to build the Crystalline Portal Nexus (92 construction, but can be boosted from 84). If you cannot build the highest Nexus, you can either use a 3×3 layout with the Gilded Portal Nexus and sacrifice some potential teleports, or use a 4×4 layout and build some extra Portal Chambers.
Here is an example layout for a player with access to everything (feel free to adjust it to your own preferences, e.g. if you need a Gilded Altar):
2 Tick Loading
The optimal loading time is 2 ticks. Converting your PoH to load faster will save a lot of time in the long run, as well as make activites where you PoH regularly both faster and more forgiving, such as Corp/Abyssal Sire/Volcanic Mine etc. This can be done easily by following these steps:
1) Make sure your house only has one floor (delete your dungeon/upper floor). This is essential.
2) Your room layout should be 3×3 to accomodate all the useful rooms. (2×2 and 4×4 also work but 3×3 is the best size since the Portal Nexus update. 2×2 is good for alts that don’t need many rooms. 4×4 is good for accounts who can’t build a Portal Nexus and need many Portal Chambers). Any larger than 4×4 and your house cannot load in 2 ticks.
3) Your portal should be in the center of your PoH if your layout is 3×3 or 4×4 (this isn’t strictly necessary for the purposes of having a 2 tick house, but it makes the house much more user friendly. If your house is 2×2, you can have the portal anywhere, but the South-East tile is best since your character always spawns to the North-West of the portal.)
4) Organise your PoH the way you want it. Step 5 will involve moving your PoH around to actually make it load in 2 ticks, so make sure every room in the house is in the exact layout that you want it, BEFORE you start moving it around in Step 5.
5) Your goal is to get a 1 tile border of green around your house (shown in 3rd party client Instance Maps) as shown in this picture:
If you are very lucky, your PoH might look like this by default and you won’t have to do anything. If your instance map however has extra tiles of grass on any of the sides, it can easily be fixed by moving your entire PoH South-West.
If moving your PoH south-west once doesn’t fix it, try it 2-3 times. If it still won’t work, you have probably forgotten to delete your basement/upper floor.