@Nimster Win Would urge you to never disclose your private details on the Internet.The restaurant/cafe industry has one of the highest failure rates of any industry.

Some more details about the property:Duplex with illegal basement unit - I can expand each unit into basement and attic to raise rents significantlyPrice: $310k, ARV 580k.

There are more details but I tried to summarize to make it an easier read.

This is not meant to be biased, but you will find it surprisingly hard to discuss fine project details and give important direction over cell phone with someone whose English is not good.

There is a meetup that @Charlie MacPherson runs, he'll jump in and give you details. 

Details, Home is Mortgaged for $150,000, Value is higher around $200,000.

Even if you decide to switch the nature of the heating system, you should, and still may well be required, to perform this analysis.A detailed heat-loss model will also help you prioritize and plan improvements to the building envelope - such as air sealing and insulation.A few missing bits of information,  which may assist the BP community to provide you with some helpful ideas, include:size and organisation of the building: SFH, duplex, triplex, etc.

But we have a plan to get there in the not too distant future ... my next post will detail my plan , just thought I should leave something to desire on that front before I dive in :) 

The questions I have relate to the details of the transaction (should the loan amount be the original amount, or the current remaining balance?

In my area, most general contractors will come bid a potential job for a nominal fee ($75-100, applied to the project if you buy and use them) and take as long as they need to come up with a detailed bid.