Product review (5 stars): Dynamite - big difference in keeping out the cold
This device really does work. Our once cold laundry room is now room temperature with the rest of the house. The old sheet metal flapper was impossible to keep clean and lint would prevent closure allowing outside air to back flow into the laundry room.

I had a unique installation problem that was easily solved after a few trips to Home Depot :-)

My vent opening is slightly below a gas meter so using the supplied elbow in a vertical orientation right out of the opening would not work because the unit ran into the meter.

So, I put the elbow on horizontally and attached a short, 4" flex vent which ran horizontally on the outer wall until it cleared the meter. I then used a sheet metal elbow to turn up into the cylinder containing the floating cap, where the Hearland elbow would normally attach. This is a friction fit. This worked flawlessly. However, I suspect that I am not getting 100% of the insulation capability due to the fact that part of the outside line is metal so there is likely a little bit of air cooling in the line occurring, but since the floating cap seals well, conductive flow is probably at a minimum. So, if you have this problem, standard hardware store 4" vent fittings will plug into this unit nicely.

I did have to by a "starter" ring for the in-wall attachment to create a female-female collar that attached into the existing dryer stub and the Heartland elbow. No problem - it went smoothly.

If you have a cold laundry room and the problem is back flow from the dry vent, you *need* this little jewel. In our case, it will save a lot of heating costs because our laundry room is integral to the main living area rather than in a garage or a basement. No more cold draft.