Tag Archives: Floor

Floor Ducts


This post will talk about the leaky floor ducts and the solutions applied to reduce my electrical consumption. It is a continuation from my post on 9/23/2014 which focused on a new thermostat. You can read the previous post by clicking here.

Catch up:

Basically, I received an electric bill that seemed higher than what I wanted to pay. The result was that I examined my residence and evaluated potential solutions. The three solutions selected were:

  1. Install a new thermostat to better use conditioned air.
  2. Seal the leaky floor vents to mitigate losses.
  3. Hire a professional to service the Heat pump unit.

Today I will write about the leaky floor vents and their repair.

The Problem – Leaky Floor Vents

As part of my examination to determine effective ways to reduce my personal electrical usage I lifted up the floor vent covers to see if any problems were apparent. Well I was very surprised to find lots of problems (I had my floors completely redone four years earlier when we moved into our current home and part of that was installing new wooden decorative floor vent covers). I wrongfully assumed that these vents would be in perfect working order.


Floor Vents/Ducts
The vents that were supposed to be working just fine.

Unfortunately, I do not have any before pictures to share because this occurred before I started writing. However, I can describe it fairly graphically. There are 10 floor vents in my home, I examined nine of them. Of the nine floor vents I examined all of them had gaps around the edges of at least a penny thickness which allowed air to escape directly into the crawl space. Four of the floor vents had severe problems, two of these were completely disconnected from the floor and just hanging in the air. Its amazing any air flow made it into the house. The other two severely problematic vents were partially detached or had gaps greater than two finger widths allowing for severe loss of conditioned air. In one of these gaps I could see daylight through the crawlspace vent and the floor connection ductwork.

Update: I located a before image.

Floor vent before repair
One of the worst floor vents was disconnected from the floor. The image quality is poor and I attempted to sharpen it for better viewing.

The Solution – Seal the Leaky Ducts

An hour later I was driving to the hardware store (Ace Hardware) with three children. We examined the possible supplies and ultimately purchased a box of medium length wood screws, a box of nails and three cans of appropriate expandable spray foam insulation (about $30.00 for everything). Once back at home I went to the tool chest and removed my electric drill, a hammer and some screw drivers. The following steps were followed for each vent:

  1. Remove the vent cover.
  2. Ensure the vent is flush with the bottom of the floor.
  3. Securely (preferably with screws) attach the vent to the floor and/or surrounding support beams. Screws are preferred because they have a much lower incidence of coming loose over time. The nails were used in spaces where screws were not possible due to space constraints.
  4. After the floor vent is as flush as possible and firmly secured (4-6 screws per vent typically). The spary foam insulation was sprayed into all remaining cracks (the exterior windows were open for ventilation and the air unit was turned off to prevent it from blowing the insulation before it dried and set).
  5. Once all gaps were sealed the vent cover was put back in place the insulation allowed to dry and ventilate.


I have checked the repairs and the insulation and vents are exactly the same as they were six months ago.

Floor Vent/Duct air sealed
The is a photo inside the vent where the spray foam insulation is visible and still in place.

The next article will focus on two topics. The first will be getting the A/C unit serviced. The second will be a cost/savings analysis looking at the expense of these three solutions compared to how much they have saved after five months.