I was advised at the time that this was sufficient that if anybody ever complained about its being used as such (triplex rental property) this would be enough that any court would sustain the current use regardless of zoning or if it had been continuously occupied or not.If the property has 3 electric meters or other improvements that likely had permits in order to be converted for use as a triplex, then regardless of whether it had continued occupancy or not it might be OK.That said,  I am no land use attorney and you should probably ignore me and talk to one of them.I guess the other question is what constitutes 'high environmental standard' - high efficiency heating, plumbing and electrical is comparatively easy in many cases.   

More doors under one roof will run more efficiently, so you shouldn’t use this to compare an 8plex to a 40unit property..

@Terry Garrett I believe purchasing cash and financing on the back end is the most efficient way but not necessary if you do not have the wherewithal.

However, I will say to do this well (in one day) the contractor would have to be working extremely efficiently and no their way around this stuff.

They also have made efficient use of the backyard using it to grow a lot of their own food. 

That’s what I was going to do originally, go with the most cost efficient option.

Lease break charges can be mitigated by finding another qualified resident efficiently.

You'll get a better return and start realizing efficiencies of scale.

It rings of the Market is Efficient theory, which maybe true in the stock market but is not really true for real estate.I can buy a building in an area with 5% cap and I can pay the equivalent of a 10% cap.

It’s also created efficient relationships with my clients as they build their portfolio and need management because I share their mindset and concerns.