Author Topic: Covering Air Vents in the Winter  (Read 14848 times)

Wesmon

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Covering Air Vents in the Winter
« on: November 16, 2014, 08:39:09 AM »
Does anyone else cover their air vents in the winter?     

We live in New England and have central air and base board heat, so our ceiling air vents are not in use in the winter.    I noticed that in the winter it feels as though cold air is literally pouring from the vents even with the louvers in the closed position.

I had the brilliant (IMHO) to use the Frost King window insulation kits to cover all the vents.  Many years ago I bought a pack of of the window films and I'm still on the same kit about 6 years later.  When I ran out of the double sided tape from the kit I bought some Scotch double sided tape at the dollar store.  The first year I used a hair dryer to shrink the wrap so it would look invisible.  I didn't do that again because I though it looked just fine with some wrinkles in the plastic and it was pointless to waste the energy with the hair dryer.

It blocks the cold air and feels much better.  I don't know how much money I'm saving but I'm sure there is some savings on heat.

Does anyone else do this or something similar?   I've seen the magnetic covers but those seem relatively expensive (my $10 kit has lasted 6 years so far) and I can't imagine them providing an airtight seal.

Mr. Rich Moose

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Re: Covering Air Vents in the Winter
« Reply #1 on: November 16, 2014, 10:47:19 AM »
If you can remove the register "grill" and expose the vent, you could just cut pieces of rigid insulation and fit them in. 1 2"x4'x8' sheet of DuroFoam EPS should do nicely. http://www.plastifab.com/products/insulation/durofoam.html  This brand is usually a little cheaper than the Owens Corning Pink Panther stuff and just as effective.
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TheThirstyStag

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Re: Covering Air Vents in the Winter
« Reply #2 on: November 16, 2014, 11:39:38 AM »
I second the foam idea. 

I just bought a large board from Home Depot and made a box cover for my whole house fan.  High insulation value for not very much money.

I also use this type of styrofoam insulation board to seal gaps in between cabinets that somehow are exposed to the cold attic in my place.  I used to get the cold air "spewing" feel that you described.  A little cheap insulating foam board sealed it up nicely.

EcoCatLady

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Re: Covering Air Vents in the Winter
« Reply #3 on: November 17, 2014, 01:00:26 AM »
I have an attic van vent in the ceiling that I cover every winter - I've tried a whole variety of contraptions over the years so here are my conclusions as to what issues are important.

1) First and foremost you want to block the wind - so you want something that has at least a covering of plastic to make sure no wind gets through. I tape up a single layer of bubble wrap under my contraption just to make sure no wind is getting through. (tape is strong enough to hold one layer of plastic, but it's hard to get it to hold much more than that - in my experience at least.)
2) Secondly you want something with a decent R-value. The foam board is a good choice, but if you're too cheap to buy something (like I am) you can use anything you happen to have on hand that will trap air - numerous layers of bubble wrap, several layers of old blanket, a hunk of fiberglass insulation or stuffing from an old pillow. You do want to make sure that your contraption is rigid enough so that it won't sag though. My current contraption uses 3 layers of an old blanket made rigid with some small wooden dowels that I had on hand.
3) You also want to block radiant heat as this is a big source of heat loss. I used a hunk of an old mylar space blanket, but a layer of tin foil works too.
4) The real trick is getting the sucker to stay in place without totally destroying your ceiling area and/or your neck! I've tried tape, magnets, screws, tacks, but finally settled on velcro. Getting the velcro to stick to plastic is a challenge, but if you get the kind with a sticky backing it works pretty well.

Good Luck! Whatever contraption you come up with, it will certainly be better than nothing!


dragoncar

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Re: Covering Air Vents in the Winter
« Reply #4 on: November 17, 2014, 11:54:21 PM »
I have an attic van vent in the ceiling that I cover every winter - I've tried a whole variety of contraptions over the years so here are my conclusions as to what issues are important.

1) First and foremost you want to block the wind - so you want something that has at least a covering of plastic to make sure no wind gets through. I tape up a single layer of bubble wrap under my contraption just to make sure no wind is getting through. (tape is strong enough to hold one layer of plastic, but it's hard to get it to hold much more than that - in my experience at least.)
2) Secondly you want something with a decent R-value. The foam board is a good choice, but if you're too cheap to buy something (like I am) you can use anything you happen to have on hand that will trap air - numerous layers of bubble wrap, several layers of old blanket, a hunk of fiberglass insulation or stuffing from an old pillow. You do want to make sure that your contraption is rigid enough so that it won't sag though. My current contraption uses 3 layers of an old blanket made rigid with some small wooden dowels that I had on hand.
3) You also want to block radiant heat as this is a big source of heat loss. I used a hunk of an old mylar space blanket, but a layer of tin foil works too.
4) The real trick is getting the sucker to stay in place without totally destroying your ceiling area and/or your neck! I've tried tape, magnets, screws, tacks, but finally settled on velcro. Getting the velcro to stick to plastic is a challenge, but if you get the kind with a sticky backing it works pretty well.

Good Luck! Whatever contraption you come up with, it will certainly be better than nothing!

Cool, I'm about to build one such contraption myself.  But I'm going to put it on the attic side of the fan.  I'll probably build some kind of box out of rigid foam, possibly stuff some fiberglass inside.  Amazingly, those thick foam boards at home depot seem to have a really low r-value for their thickness!  I would use random found materials, but I'd like to build something that will last multiple seasons

homehandymum

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Re: Covering Air Vents in the Winter
« Reply #5 on: November 18, 2014, 12:46:53 AM »
I have a similar problem, but it's the ventilation from a bathroom, so I don't want to completely block it up.

The problem is, that the outside hole is easily 6inches square, and only covered with a slatted grid, not a louvred or otherwise valved covering.  The vent is, naturally, south facing (uh, that is the cold direction here), so whenever the wind blows from the south, we get a cold blast of air dumped straight into the bathroom.

The kids never remember to shut that bathroom door, and it's the downstairs one, so is in use all day.

An additional problem is that there is a pipe (maybe an inch and a half diameter) running down the outside of the vent, from dodgy plumbing decisions involving a previous owner and the upstairs bathroom, so I can't easily whip the old cover off and replace it with a better one.

tldr: is there any way to fit a wind-block on an external vent, that can accommodate a vertical pipe through it, which will still allow air to flow out of the house??
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KC1983

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Re: Covering Air Vents in the Winter
« Reply #6 on: November 18, 2014, 07:31:22 AM »
If there's cold air coming through your vents when the heat isn't on, you have an insulation problem. What that means is when those vents are in use a lot of warm air is going bye bye. It might be worth talking to an older, experienced HVAC technician about how to optimize your system.

The bigger issue that no one here has mentioned is that if you close off more than about 20% of the vents you risk damaging the heater/air conditioner. Those systems are designed to move a certain amount of air, and blocking lots of vents puts a restrictive pressure on the part of the system trying to move the air.

VentSTOP

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Re: Covering Air Vents in the Winter
« Reply #7 on: January 07, 2018, 10:01:49 AM »
I found this site doing research for my business and can tell I am going to be a frequent reader of the material here - what a wonderful information source and exchange!  That said, I can't help but respond to this thread because we hear of SO MANY home-grown solutions to stopping drafts from unused central air conditioning vents, which is exactly why I created VentSTOP.  Ours is the most effective solution (cost-wise and functionally) to this age-old and often ignored problem.  Please visit our website at [link deleted - MOD] and I think anyone looking to save MONEY, save energy and just be more comfortable will LOVE VentSTOP!  Again, sorry for the shameless plug - this is purely a PSA!  All the Best, Justin.  Owner, VentSTOP
« Last Edit: January 08, 2018, 07:01:02 AM by FrugalToque »

Shinplaster

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Re: Covering Air Vents in the Winter
« Reply #8 on: January 07, 2018, 12:21:47 PM »
Use these.  Easy on, easy off, and no tape residue.        https://www.walmart.com/ip/Deflecto-MVCX-512-Magnetic-Vent-Covers-5-x-12/24616264

You can also find larger ones, and they are easy to cut to size if need be.
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BudgetSlasher

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Re: Covering Air Vents in the Winter
« Reply #9 on: January 07, 2018, 04:26:10 PM »
Do you use the central air? If not any fix that obstructs the ducts is probably perfectly fine.

But, if you do use the central air, I'd be concerned you are only addressing half of the issue. If there is cold air leaking into your ducts, either from lack of sealing at the joints or running through uninsulated spaces (such as the attic without its own insulation), then you are probably having the opposite problem during cooling season when the ducts are under pressure with cooled air. It could either be blown out of the same badly sealed joints or allowing your hot attic to warm the air in uninsulated duct work.

Obviously sealing and insulating the ductwork is more time intensive and has a higher upfront cost, but, at least for me, in the long term it is the right way to fix the problem.

HipGnosis

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Re: Covering Air Vents in the Winter
« Reply #10 on: January 07, 2018, 09:14:16 PM »
I've blocked the heat vents for my laundry room and spare bedroom / office / storage.

First I taped cardboard to the vents w/ duct tape.   That didn't last long - the furnace blew them partially off.
So I took the vents off and cut 2" stiff insulation foam to fit in the duct behind the vents.