Ask Ted!

If you have any questions you want answered, feel free to drop me a note. If you’ve got a question, chances are, there are lots of others out there with the same question. So ask away!

Note: all comments are moderated unless I’ve approved one of your previous comments. Almost everybody gets thrown off by this, but I moderate comments to avoid spammers. The downside of this is that you won’t see your comments post until I’ve had a chance to review and approve them. Sometimes this can take days (sorry!) Thanks for your patience.



863 thoughts on “Ask Ted!

  1. Hi, I use forced air to heat and cool my place and I noticed that air comes out of my intake (or return) vent when it is windy outside. Does this mean that my ducts have leaks? Thank you.

      • Typically, the answer is yes, this would indicate that you have leaks.
        There are times when cold air will “drop” out of the return vent. Since cold air is denser and heavier, if the air in the ducts gets cold, it will create a draft. Just like sitting in front of a cold, but totally air-tight, window, you can feel the cold air flow.
        However, based on your description, since it increases with windy conditions, it is highly likely that you have significant air leaks.
        If you feel how much cold air comes out of different vents, both returns and supplies, you may be able to find the closest vent to the largest leak. If it’s just your return, then it might be something as simple as the air filter slot on the air handler (is this in your attic?). Many times I’ve seen the filter slot open wide to the attic, allowing all sorts of cold/hot air and dust into the system. If your system is like that, then you can just put tape over the slot after replacing the filter.

        If the air handler is in the attic, then it’s worth checking it for air-tightness. You can caulk or tape with foil tape after cleaning seams around the air handler. That can make a big difference to efficiency and hence your utility bills.

  2. HI Ted! Thanks for having such an informative site! I am about to do some insulation work on a 1920 farmhouse and wanted to get some opinions. It’s a 2 story 2400 (ish) sq foot farmhouse with a stone foundation, metal roof and wooden (poplar) exterior walls covered in vinyl, and oak beadboard for the inside walls and ceilings (no sheetrock or plaster except in the kitchen and bathrooms which are additions, and there is sheetrock over the wood in the living room and downstairs bedroom. There is no basement, but a crawlspace under the house with stacked rock foundation. The floors are also Oak with no subfloor. I’ve been in the house for 6 years. The walls are pretty tight, (someone blew foam into at least some of them). However the floors and ceilings are quite drafty. I’m planning to spray foam the attic floor – that seems pretty obvious. My questions revolve around the crawlspace. The stone foundation is currently quite open. There is some fiberglass insulation under the floors and it’s molding and falling down. – that clearly has to come out. The mold is not severe, and the space without the insulation might be OK as is, though I do see some mold on the wooden walls, which is not acceptable. The stone foundation and wall supports are quite irregular, so sealing the foundation off completely seems daunting if not impossible. It has been suggested to me to put plastic down over dirt, and spray foam on the underside of the floor, but leave the foundation walls mostly open for venting. Does this sound like the correct approach?

    • Given your construction, you have to be really careful about moisture buildup in the house that would seep through the leaky walls and ceiling and cause problems. Having no sheetrock and just wall boards is asking for trouble as you tighten up the house. That’s one of the unintended consequences of making an older home more energy efficient. As it was originally, the home was built “leaky”. What this means is that during the winter, the cold, dry air would flush out the interior humidity, making it much less likely to build up inside the walls and ceiling. As you tighten the home, the humidity inside increases, making these issues more of a concern. So please keep this in mind.
      That being said, for your crawlspace, definitely – seal the underside of the floor so all the ground moisture doesn’t rise up through the floor and into the house. Plus, adding plastic over the dirt is and important part of the solution. Note – there’s a correct way of doing that so it’s effective. You want two layers of plastic with seams staggered and taped so there’s no way for water to come up. The plastic should also go up the walls a bit. If you have someone spray-foam the underside of the floor, have them foam the plastic to the wall so that it forms a permanent seal. If it’s really tight, you’ll probably even find pools of water under the plastic when you’re done. That’s fine – it means all that water isn’t entering your home. However, if it’s extreme, you may want to have an automatic sump installed at the low point so that the water will periodically get pumped out.

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