You will need to make sure there is duct work running to the room for heating and cooling, proper insulation, a window or two, etc.3.

Thanks city of Milwaukee, another 10k price drop to accommodate new hvac, going from the boiler system to forced air.All in all the work done to the property included:27 new windows2 new furnaces, ductwork and water heatersNew PEX plumbing along with accompanying fixturesDrywall work and insulation to remedy water damageNew roof (6 layer tear off)Refinished hardwood floorsNew cabinets, countertops, etcGutted bathroomsPaint abound Etc, etc, etcBeing the largest project I have undertaken, I ate two months of holding costs in getting the property ready for rent as I grossly underestimated the amount of time it would take to get the property ready.  

Or should I cut all of it out and ha e furnace installed with duct work?  

There is forced hot air in the house now, so the duct work is there.

Best thing that I have done is to charge a monthly pet fee and then put in lots on language in the lease stating that they have to have the ductwork and any carpets professionally cleaned at the end of the lease showing a receipt from a 3rd party explaining the next tenant may be allergic to pets.

The remediation contractor told me that I can just clean it up good w/ bleach water (wearing appropriate PPE) and have the duct work cleaned up and i'd be good to go. 

So far we have replaced the ductwork and have had some closets built in. 

Back in those days asbestos was barely new to the market and was used for many things such as siding, plaster walls, insulation, duct work and even shingles.

I’m not trying to rain on anything here but the reality is that measuring Btus delivered to individual units via airflow is by its very nature imprecise - if you want to know why, read on...The size and length of the ductwork is but one factor ( of many) that will yield energy losses while that warm air is being moved to your units.

It's a 40 year old property, so the duct work, electrical, plumbing is outdated and weird, and I'll have to make the windows larger to be up to code for a bedroom -including cutting through the concrete and digging bigger window wells.