My house was built 100 years ago and has never had central, so no ductwork either. 

New shingle roof - $6-8 per sq ft New high efficiency furnace and all new duct work with 8 reagiters - $5000-7000New high efficiency tankless water heater with new 1" gas line. $3500-5000New hardwood flooring with stain - $10 per sq ft. 

All meters already present, space for furnace already made.This work would include running black pipe, adding ductwork and returns, installing furnaces and AC unit and any other required plumbing. 

We are expanding and also adding a new story to a townhouse in Georgetown and need an investor-friendly HVAC contractor to do all the duct work and install another unit can you recommend a good one with reasonable prices?

But when I say full gut and rehab I'm talking: taring everything down to the studs, updating plumbing and electrical throughout, probably upgrading the panel, adding duct work for heating and cooling, new mechanicals (boiler, A/C, etc) , hardwood floors, new kitchen, new dry wall and insulation, paint, finish work, etc.

She says the exterior cedar was repainted, new roof, new AC unit and air handler, new ductwork.

We've had the same tenants the last 18 months.Rent: $1,350/monthMortgage, Ins, taxes: $960/monthOur initial plan/goal was to acquire properties and hold them for long-term (20-30 years+) to essentially have the tenants pay for the mortgage and we would make a decent cash flow profit annually and then eventually have a solid asset (trying to diversify investing, e.g. not having everything in retirement accounts/stocks)Just recently the A/C had some leaks and is pretty much on it's last leg and needing a replacement (quote of ~$8-$9,000 installed + fixing leaks in duct work).

By running electric hot water heater you don’t need a ductwork for ventilation. 

These will tell you how much you home is leaking and the leakage of your ductwork.

The duct work was sized at the time for an oil fired furnace .