Woman of Steel

July 21, 2007

HVAC

Back when we were thinking of gutting the entire house (we’ve since opted for one room at a time), I got a quote for redoing the entire furnace ducting system: $8,000. JUST for ducts (the furnace is brand new). Yow. I love my furnace repairman, and feed his family well, but I just cannot cough up 8,000 clams for sheet metal.

Now that we are doing one room at a time, I am doing everything in one room at a time– walls, ceilings, electric, insulation, floors, ducts. It is not as efficient as doing all rooms all at once, but this method is more manageable for us (financially as well as for sanity).

So I right now, on top of learning everything else, I am learning how to repair and install furnace ducting. It is actually not terribly difficult, merely distasteful and dirty. The old ducting dates back to the 60s and some dates earlier. It is very, very dusty and rickety. Some pieces I am replacing but I am reusing most of the ducts. I spent a whole day removing everything that connects to the living room (two heater vents and one cold return vent) and scrubbed them clean. The cold air return vent was only sheet metal nailed onto floor joists in the basement, and a hole hacked into the living room floor as a “register.”

Cold Air Register

You can see the stone foundation and three floor joists through the “register” in the above photo. Unfortunately, the natural gas supply line was installed through the foundation and directly under this cold air return vent– not a very wise decision, because should the gas pipe ever leak, the fumes are dispersed throughout the house and also flow into the living room above.

When I peeled the sheet metal to reveal the joists, great gobs of greasy dirt and dust spilled out. Yuk. Thank God I was wearing a bandana to cover my long hair.

If you look closely at the picture below, you can see what I mean. This photo was taken before I removed 70 square feet of sheet metal nailed to the joists. I had removed the cold air supply duct (where the circle was) to reveal about a 1/4-inch layer of dust and cobwebs coating the joist above it. I am so glad to be rid of this filthy cob job.

Dusty Ducts

There is a system to furnace ducting. You can’t just throw ducts anywhere. Cold air vents (return air) must be positioned in interior walls, and heat ducts and registers (supply air) must be installed along exterior walls. The system of forced airflow works with the natural physics of rising and falling air. Anything else is inefficient (and against some local housing codes). As expected, the ducting system in my house is all the wrong way.

There should be a cold air return vent in every room that has a heat supply vent. Only two rooms in my entire house have cold air return vents (the living room and dining room), and they are both along the exterior wall. Thus my furnace works very hard, and the air pressure in my house is uncomfortable (think of how a cup sticks to your face when you suck in the air from the cup– it creates pressure on your face because of the vacuum you created). Also, my upstairs rooms are absolutely frigid in the winter. One bedroom (15 x 17) has a teeny-tiny heater vent on an interior wall, and that’s it. The heat leaking out of that tiny heater vent cannot compete with the two 3′ x 5′ windows and the 250 square feet of uninsulated walls and floor of that room. All winter, a thick coating of ice covers both windows, and over the years the water has rotted the window panes. I won’t even go into describing the other bedrooms. We freeze every winter up there.

So, the fundamentals are important here: supply on outside walls, return on inside walls. Have enough heat registers for your room (there is a formula for calculating the necessary cfms to square footage). And have an equal amount of cold return vents for your heat supply vents.

So I am in the process of installing another supply of heat in the living room, replacing the dirty cold air sheet-metal cob job with a closed-duct system, and patching/sawing holes in the floor above to accomodate the changes.

Furnace Ducting

Duct Project

New Heat Vent

This autumn, I have to add more cold air return ducting to the downstairs to make the system a little more efficient. Next year, when we remove the chimney, the new opening will allow me to completely reconfigure the supply/return ducting system for the second floor. The noggin on the first floor make ducting and electrical nigh impossible for exterior walls. I have to work around that!

For now, I am thrilled to be doing even one room as it ought to be done.

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7 Responses to “Woman of Steel”

  1. Karen Says:

    My Opinion

    Time to move to your own domain!!!

    Anyway, you are amazing to take on this task! I cannot wait to see more pictures of your progress.

  2. Mrs Mecomber Says:

    I did buy the domainname from Google.. but yes, I need to get my OWN home. 😉

  3. Karen Says:

    How do you get the script type signature on your post?

    You amaze me with the work you are doing to your home.

  4. Mrs Mecomber Says:

    Thanks for visiting! It’s a lot of hard work, but we are making progress!

    About the signature… I have a geeky blog, Mrs. Mecomber’s Scrapbook, and I’ll address the issue there.

  5. Mrs Mecomber Says:

    Hmmm that link didn’t work. It’s http://www.mrsmecombersscrapbook.com . I’ll keep ya posted.

Trackbacks/Pingbacks

  1. New York Renovator - June 16, 2008

    […] Oh, and I had to re-do the furnace ducting in the living room, too, because it was all messed up (not according to code) and filthy. I also […]

  2. About Cold Air Return Vents | New York Renovator - October 16, 2012

    […] I did a post about this when I renovated my living room, and re-did some of the furnace ducting to the room. I had done some studying and talked with my furnace guy. You can read the post here. […]