You got a good price! My single floor, 2000 sqft costs $450. And IMO it is worth every penny! The price actually is not computed by sqft, but by the number of vents. Ask those subs just who does a full duct cleaning for a couple hundred? *IF* they can name someone, check 'em out, but I think the subs were just blowing hot air. You can DIY -- and it won't be nearly as good as professional, but 1000% better than nothing. Seal the duct entry at the furnace, and all vents other than the one you are working from. Wear a dust-mask and goggles. Use the rods for a chimney brush and attach a slightly-smaller-than-duct-sized bundle of soft rags. Start with the vent farthest from the furnace. Run rag-bundle through the duct as far as you can reach, swirling and brushing the dust towards you as you pull the rod back. Vacuum the accumulated debris. Do not swear at the amount of splfft. Repeat the brush-swipe until there are no more wood chips, screws, nails, metal filings, plasterdust or sawdust. Repeat the process at each vent opening. The last vent should be the one at the furnace. Vacuum that vent and duct. Remove the seals from all vents. Done. The first time I DIY'd mine Without skill or practice, (and not the proper tools) it took me ten hours . It takes a pro about 2 hours AND he does a vacuum of all duct surfaces -- much better than brush alone. Please consider not only the health aspects [who really wants to breathe dust-laden air??] but remember that not cleaning the ducts will just about guarantee your furnace is going to get dust-filled, which is not good for the electronic controlss and worse for the burners and mechanical parts. Cleaning the furnace --assuming it won't need repairs-- will cost almost the same as the preventive duct-cleaning. In fact, read the HVAC warranty carefully, because sawdust and plaster-dust deliberately left in the ducts just might void it.

not much you can due without costing you lots of money to either replace/relocate. location of furnace is decided by where the chimney is located on houses. if it is a furnace that will be needing replacment soon you could then get a high eff furnace and vent it out the side of the house and then move the duct to the outside wall where it is not in the center. of course the hotwater heater would have to stay in its place or upgrade to a side wall chimny as well.most would just soffit around the duct and put in prop ceilings

Thanks again, mike. Interesting that the placement of the registers is not that important. In our last house we had a combo system, meaning the Forced hot air furnace was also the air handler. There were only one set of registers just above the baseboards and we were told the low placenent of the registers was not very efficient. It was a house built on the 60s. I assume the joists run parallel to the duct bc that's the direction of the Floor joists visible from the basement. I was thinking to simply reuse this duct and reconnect to to the registers for the dining room and living room, and add three new registers for the kitchen to replace the exisitng registers in the duct. Thanks again

How UV Air Scrubbers Work. https://www.newcentralairconditioner.com/ This is essentially the same technology hospitals are using to disinfect rooms. An Air Scrubber uses the same sanitizing power to inactivate airborne contaminants. They are so effective they are used in hotels, cruise ships, hospitals, schools, major league ballparks, and even the pentagon. The Air Scrubber is installed within your HVAC system. It’s typically placed on the supply side of the ducts, downstream from the blower. Oxygen and water molecules from the air enter the purification unit and pass through the honeycomb matrix. Using a UV light and proprietary catalyst the molecules are then transformed into safe, yet powerful oxidizers and once released the molecules become supercharged purification oxides which seek to rapidly destroy up to 99% of contaminants, fungi, mold, viruses and odor causing bacteria leaving the air cleaner and healthier. Once installed there are no filters to change and no maintenance required. Benefits of Air Scrubbers. They mitigate mold: In humid climates, such as Arlington’s, your home needs a strong defense against mold. And one place mold thrives is in your ductwork. Ducts are dark and cool and moisture in the continuous stream of air creates the perfect breeding ground. The Air Scrubber prevents mold bacteria from spreading beyond the evaporator coil, where outbreaks commonly develop. Fresher air: Mold carries with it a foul, sweat sock-like odor. The Air Scrubber neutralizes mold spores before they have a chance to stink up your home. Healthier air: People sensitive to mold exposure can experience symptoms such as allergic reactions, sneezing, red eyes, runny nose and even severe reactions such as shortness of breath and even asthma attacks. The Air Scrubber renders mold spores inert, making the air safe to breathe. Beyond mold: Air Scrubbers also tackle pollutants such as volatile organic compounds