My apartment’s on the 2nd floor of a 4-unit brick building. I started my work by examining the doors. The front door leads to an indoor stairwell, so it’s not as much of a heat loss risk as the back door that leads outside; nevertheless, there was a gap of nearly 3/4″ beneath the front door (not to mention the fact that the door’s main panels are made of mere 1/4″ plywood!). The doorframe is metal and is in good shape.

So I went to Lowes and bought a selection of door weather-stripping solutions, not sure what would work best. I settled on a vinyl door bottom sweep, with three fins, that I nailed to the bottom of the door; of course, that meant removing the door at the hinges. That covered about 1/2″ of the gap. Then I installed a hardwood threshold that I screwed onto the existing wooden threshold. I later stained it to match the dark wood of the door; that covered the rest of the gap, providing a fair seal for the bottom of the door. I used a roll of EPDM hollow-core weatherstrip to seal the rest of the door. It’s not airtight, of course, but it’s a vast improvement over the way I found it.

The back door leaked air something fierce. It’s a typical double door: an inside panel door of wood (glass upper panel), and an outside storm door of metal and glass. I installed a new rubberized door sweep for the outside face of the outer door (the old one had crumbled away to nothing) and I rolled out a self-stick foam rubber weatherstrip onto the inside doorjamb. Now, when the doors are both shut and I put my hands down at the lower corners, I can feel only a tiny draft of cold outside air coming in. More tweaking to do, I suppose; or get a door pillow.

Air leak at intake duct

Back in the basement, I’ve examined my unit’s furnace and noticed a couple of significant leaks: the first I found is on the intake side, at the base of the unit, where the filter slides into the galvanized intake ducting—it’s a loose fit, so lots of basement air gets pulled into the system. Given that the basement, so far in my one month’s residency, has not been cold (despite outside temperatures often in the 20s and 30s), this may not be a huge problem. But since a forced-air heating system operates on a feedback loop, eventually there will be an efficiency loss. As the apartment warms up, the return air going down to the furnace would normally tend to get warmer; cycling the ever-warming air allows the thermostat to reach its preset temperature sooner than if only outside air were pumped in. But the leak at the furnace intake is interrupting that feedback, requiring the system to run longer to heat my apartment than it otherwise would do.

Furnace out-port leaks

I found a second leak in the furnace, this one on the output side: at the very first joint, the round duct is not seated properly into its hole in the side of the furnace wall. Hot air is blowing out into the basement. That partly explains the comfy temperatures down there! I’ll pick up some silver tape patch that leak.

Next stop: the windows! There are storm windows all around, which is good. With my hands, I’ve felt along the edges of the windows and felt no obvious drafts so far. I may go as far as installing those plastic “shrink-wrap” window covering kits, but I’m not convinced I need them.

~Ben
AltE