A gravity furnace is not a forced air furnace (no mechanical fans pushing air) so it heats up air in one central location which then rises through the ductwork to heat the house and then when the air cools and it becomes more dense then hot air and thus falls down through the return ducts back to the furnace to be heated again creating a slow cycle of convection.

@Zachary Bellinghausen  One issue that’s going to come back to bite a lot of sponsors (and their LPs) at this point in the cycle is their misunderstanding of exit cap rates. 

California is another market that cycles every 7 years or so.

But there's no way to know what part of the cycle you're in until it's over and you look back on it.

I have been doing this in USA market, started in 2011, Atlanta and now Detroit marketAs far as Oz markets go its been brilliant in Syd and Melb if you purchased during the beginning of the boom cycle in 2013 and sold out prior to peak. 

However I was able to find the following that we all agreed on:A GOOD CPAAN EXCELLENT  probate/trust ATTY An excellent RE agentWith the above and and a *lot* of teeth knashing and fighting we were miraculously able to come to an agreement we all could live with.

This type of estimate will work for some types of houses, at some time of the year, at certain points in the economic cycle, in some locations, using some types of materials, some types of contractors, with a certain level of negotiating skill on your part.Long story short, unless you're comfortable going back to the seller after doing a detailed analysis and telling them that you were way off in your estimate, I wouldn't use this method.Instead of trying to estimate a rehab in less than one minute, I would recommend learning a more detailed methodology, and spend 10 to 15 minutes getting a much more accurate estimate.Just my $.02...

If you need referrals, feel free to PM.Here're a few articles to give you additional guidance. https://www.biggerpockets.com/member-blogs/10850/76728-questions-to-ask-a-syndicator https://www.biggerpockets.com/member-blogs/10850/86621-six-steps-approach-to-getting-started-in-real-estatehttps://www.biggerpockets.com/member-blogs/10850/81214-what-goes-up-must-come-down-or-market-cycles-fluctuationhttps://www.biggerpockets.com/member-blogs/10850/80091-you-cannot-force-a-rain-but-you-can-force-a-property-to-appreciate

In theory it is simple enough but then you run into issues like move in/ move out dates not lining up with your billing cycle, tenants who complain they don't use as much water as others, notifying tenants and collecting payments etc.

That cycle repeated numerous times before they moved.