How to Heat & Cool 3rd Floor

[bjb345]

I need help deciding how to heat and cool my third floor! I live in a classic American four square in Pittsburgh. The house is about 3,200 square feet. First and second floors have forced air heat and no A/C. The third floor was originally heated with gas stoves. The original gas lines are still there. There are three rooms on the third floor and a landing. The third floor and roof are high up, and there are dormers on all four sides. The house isn't insulated in the walls or attic. I do have access to the attic above the third floor. I'm starting to re-do the first of the rooms on the third floor, which includes removing all the drop ceiling and weird 70s fake wood paneling that was put up on a massive network of random wood face nailed into the plaster, repairing plaster, and rewiring. I can't get too much farther until I decide on HVAC.

I've considered all the options I could find:
--Extend existing ducts to third floor: too much tearing up walls with limited results because of how far the furnaces would have to push existing air
--Add another in the attic or a closet to serve 3rd and maybe 2nd floor with A/C: interesting but costly option with a lot of tearing into walls
--Go back to original gas stoves: would be awesome to have gas stove, but the room will be a kid's bedroom, plus I'd have to run a new gas line from the basement, cause no one will tap into existing 100-year-old line, plus put a liner in the chimney, which with the cost of a stove I think runs me $4,000 to heat one room
--Minisplit: all the rage but not excited to put holes in my house or about how the indoor or outdoor units and lines look, plus my house is so high, that it would be a long run from the ground unit to the third floor rooms
--Radiant floor: sounds cozy but too involved since I'd rather not tear up floors and not excited about needing a boiler
--Electric baseboard: would be very cheap to install because I'm doing the wiring myself, and it could be removed later with minimal damage to the room, and baseboard is relatively kid-friendly, but I don't want to cover up my recently liberated baseboards and it'll be expensive to run and probably not terribly warm as the primary heat source in an uninsulated third floor
--Electric wall heater: also would be cheap to install and relatively non-destructive and reversible and mostly kid-friendly though possibly hot to touch, also could quickly heat the room so we could turn off during day, but wonder about operating cost and capacity and worry about fire hazard
--Give up and embrace the third floor as our seasonal vacation home for the spring and fall
--Rent a condo

I think I'm leaning toward an electric option, since I'm not convinced that the alternatives that involve major work and money are worth it, and I like that I could do electric myself for less and with minimal disruption to the old house, and I could still be able to switch to something else down the road (though I will have repaired all the plaster and not love to open anything back up).

[mjt]

We went through this same decision making process when we finished our attic a few years ago. Our attic is significantly larger than yours which changes the calculus a bit (ours is ~2000 sq ft). We have hot-water radiators for heat on the 1st and 2nd floors, with in-floor hydronic in the master bath & kitchen and electric in-floor heat in the "kid's bath".

We ended up doing a separate gas forced air furnace with central air installed in the attic. The ductwork race-tracks around the perimeter of the attic so is behind the kneewalls. We installed central air registers in the ceilings of the rooms on the 2nd floor which makes up a second zone. We'd completely gutted the attic, though only 30% of it had been finished originally. The disruption to the rest of the house would have been minimal as we only needed to run a gas line and water drain line from/to the basement. I say "would have been" because we structured all our renovation work in a way that the mechanical rough-ins for the kitchen, master bath, and attic were all done at the same time.

There's a lot about our attic project on my blog. The first posts are February 2013 and the last is February of 2015...

[Mick_VT]

I might consider a new unico system (https://www.unicosystem.com/) just for the third floor, independent from the rest of the house.

[phil]

If you consider electric, check if your panel has the capacity. If it does, baseboards is probably one of the cheaper solutions, maybe cheaper upfront anyway. If you need a larger panel then you might need a new meter base, thicker wires to the poles. I did that but it was a bit to go through. at least now if my gas heater craps out I can use plug in heaters for the interim. Gas may be cheaper per BTU.

heat wants to rise but you can get heaters that are downdraft style, made to blow down instead of up so maybe one could be creatively located.

I built a box for my AC unit into my attic space, a bit of ductiong and whatnot but I didnt; want to block the window and I was able to do that without knocking an ugly hole or anything. I added blowers to ven the attic through the box and out and one to bring fresh air in and cool it. Its probably not that efficient but it works when it's unbearable and its quiet. they do make portable units so I sort of copied the ideas from that.

[Jeepnstein]

Ducted minisplit attached to a plenum. You don't have to punch all those walls full of holes to do it. The price is right. I have two of them running in my house.

[Gothichome]

First off Bjb, welcome to the District. As you see you are not the first person to have this problem. A couple of questions, you mentioned the gas folks are hesitant to connect into the existing gas lines, do you know if they have been abandoned as the source in the basement? If not they may still be under pressure, in my view this indicates a sound gas line system. I see no reason why it should be an issue to connect a new appliance. If it has been abandoned I think I might consider using the space taken up by the pipes as space to run electrics, just remove the pipe. Your talking about an A/C system as part of the heating plan. You will need thirty amps available at the panel, do you have that? If so you could run your power up into the attic and run an electric furnace/AC unit and mini duct it into the ceilings. Pretty straight forward install as I see it. The down side as mentioned by others is the cost of electric heat, but it might be offset by the ease of installation.
If electric is not the option you might be able to run a new gas line up an outside wall and into the attic and instal a gas fired unit with mini ducting. You would still need to get 30 amp or so up there for the AC component but you would be heating with a much cheaper fuel.
Just my thoughts. Once again welcome, has any one mentioned we like pictures here in the District yet?

[bjb345]

Thanks to everyone for the incredibly thoughtful responses. So glad I came here!