Heat probably gets to third floor just fine, if sufficient ductwork exists.

I think when rehabbing, some folks pull out old boilers and radiators and want to avoid the upfront cost of ductwork and forced air - so they put in electric baseboards.

The electric boiler is basically a beefy, in-line hot water heater which, being in a closed system, does not have as great of a temperature lift from source water to output as a DHW inline heater would.If gas is more affordable in your area, then rather than ripping out all the existing supply lines and trying to install ductwork for a furnace - which can become expensive quickly, particularly if multiple levels or stories are involved - you could simply replace the boiler with a high efficiency (95% AFUE) gas fired boiler.

The bathroom floor and part of the subfloor in the hall and kitchen would have to come-up; the wall between the bathroom and hallway and across the end of the hall would be going back to the studs; the common wall between this apartment and the adjacent unit would need to be brought up to current {fire} code; the ductwork for the HRV needed to be replaced; and three of the existing windows had broken thermo panes.We also planned to improve the energy efficiency of much of the envelope during this renovation - the amount would depend upon what we found behind the drywall.What we found:The damage to the subfloor on both levels was more extensive than forecasted and I wasted two weeks, and a few hundred dollars in materials, over the holidays in December trying to remove the smell of pet urine (ozone, enzymes, sealant, etc).  

This project also needed the crawls space to be completely redone; new drain tile and sump pump system, foundation repair, encapsulation, rim joists and floor joist, 14 new supports with cement footings, plus the duct work, electrical, plumbing, and main drain lines... easily about $25k to contract out... my cost was about $2,200.Sometimes I say, " I save more money than I make".  

I tried explaining they need all new flooring carpet / vinyl smells like animal urine and it's all stained , needs ac unit and heat with duct work ran among a lot of other updates .

I've scheduled a vent cleaning company to come out and try to clean the vents and the furnace in the event the animals urinated in the duct work.

The range is for whether or not the house already has duct work, model choice, and regional price fluctuation. 

Keep in mind this house is in Southington, CT and is a B+ area (a very desirable area to live) which has a big impact on the rehab and the way it is structured.Draw 1Replace 1st floor gas furnaceInstall new gas furnace and ductwork for floor 2 Replace both hot water heatersPlumbing repairs/modifications: water lines, waste lines, & relocate washer/dryerElectrical repairs/modifications: relocate washer/dryerTotal Amount for Draw 1: $15,000Draw 2Remodel 2nd floor unitFramingPatch and PaintFlooring throughoutKitchen remodel: add cabinets, install granite countertops, backsplash, install appliancescomplete bathroom remodelInstall new light fixturesTotal Amount for Draw 2: $10,000Draw 3Install vinyl sidingPaint exterior trimgarage repairsfront porch/walkway repairslandscapingTotal Amount for Draw 3: $10,000Draw 4Remodel 1st floor unitpatch and paint interiorFlooring throughoutkitchen remodel: new cabinets, new countertops, backsplash, appliancesinstall new light fixturesTotal Amount for Draw 4: $10,000Total Budget = $45,000

We put around $15k out of our own pockets into it, and used an energy efficiency loan ($15k) to insulate, install new windows, and add an ASHP with ductwork.