Noise thru heat vents

[connsu]

We are staying with family in Berkeley California. They rent out rooms downstairs but could hear their entire conversations so they blocked all the forced hot air heating vents. Now the just use oil filled space heaters and the house gets pretty chilly. How expensive would it be to convert to a 2 area heating system? I also suggested a gas fireplace.

 

[Sparky617]

Depending on the construction of the house it can be very expensive running all new duct work. I have two HVAC systems for my 2500 square foot two story house. One in the basement that serves the first floor and basement and one that serves the second floor. There aren't common ducts between the two floors.

A mini-spit ductless system would be one option. Given your mild climate, you could do it with a heat pump system.

https://www.energystar.gov/products/heating_cooling/ductless_heating_cooling

 

[pjones]

If they blocked off half the airflow that the unit is supposed to be supplying then they may be buying a new Unit soon anyway. May as well open some drywall and connect the upstarts vents to a new duct and put in a small furnace. You will probably want to dump the extra air from the original furnace into the downstairs (or whatever location you end up making it serve) so you don't choke it out. It will still be over sized for the job but at least it would have the airflow that it needs.

It's not a small job but depending on the house layout it might not be too bad either. You won't really know until someone goes to look at it. We can't tell you how big or small the job is without seeing it.

You will need space for the second furnace, your gas line will need to be big enough to accommodate the added Supply, you will need to have enough room on your existing electrical supply or run a new wire, pull down the drywall and run additional duct, don't forget about the return air. All this will take space to install and calculations to determine feasibility. If going with gas then you need the space on the wall or in the chimney to run additional flu vents. There are limitations as to where it can be placed so that will take some consideration also. If going with a high efficiency furnace then you will need access to a drain or install a pump.

In short, the job could be big or it could be small depending greatly on the access to the ducts, space available, and existing gas and electrical lines.

 

[pjones]

It might be cheeper to install acoustic insulation around the branch lines and inside the trunk line. You are still opening drywall and replacing ducts but you wouldn't need to deal with the rest of the stuff that goes along with installing a second system.

Do they het any noise entering through their return air? That may be a little harder to acoustically seal.

 

[EdInKentucky]

In that mild Berkeley climate, you might consider just installing mini-split ductless units in each living area.
Remove all of the central heat / air equipment, and whatever ductwork can be reached.

Especially if you're in that house for the long haul.

These days, the mini-splits are pretty good.
Units with heat pump capability would do well in your area.

If you're paying the entire energy bill, using a thermostat for each unit, which lets you set the highest "heat" temperature and the lowest "cool" temperature, will save you a lot.