Are the units heated by radiant heating? 

Purchase price: $216,500 Cash invested: $40,000 Sale price: $320,000 Cape house flip on side road in Bristol, $48k profit sold off-market after Private Money Holding Costs, Buying Costs, and Selling Costs.Re-grade land in back of house and provide new landscaping across plot of land.Replace roofing on back end of house where active water leak occurred.Two full bathroom gut jobs with custom tile showers and radiant heat flooring.Refinished the hardwood flooring and ripped out carpet across house.New GE 4-set appliances (Refrigerator, Range, Microwave, Dishwasher).Granite countertops in kitchen and bathrooms.New finish electrical and finish plumbing across house.Two coats of beige paint at the request of buyer across house.We bought this house on-market as a Short Sale and had to re-negotiate price with the List Agent and then ultimately the bank.

Purchase price: $216,500 Cash invested: $40,000 Sale price: $320,000 Re-grade land in back of house and provide new landscaping across plot of land.Replace roofing on back end of house where active water leak occurred.Two full bathroom gut jobs with custom tile showers and radiant heat flooring.Refinished the hardwood flooring and ripped out carpet across house.New GE 4-set appliances (Refrigerator, Range, Microwave, Dishwasher).Granite countertops in kitchen and bathrooms.New finish electrical and finish plumbing across house.

If you get specific recommendations, I'd still run the search outlined and see how that reco stacks up against the herd. 

For me running the brokerage was just a free place to work and what I personally got out of it was LEADS  and deals  that were off market and brought to me by my agents that was the true financial benefit for me to herd those cats.

The house has a radiant heat system so it would be 12k-14k to add.

Don't be part of the "herd" that gets taken advantage of.

Next question - does the boiler supply just hot water or does it also provide radiant heating type of solutions throughout the building?

I've herd of a lot of people renting apartments and then staging them for airbnb.

Getting small portfolio rental property owners to unite is like herding cat's, at best, this is going to go down in history as the #1 way to achieve exactly that.