Author Topic: Replacing register & return air vent covers  (Read 1008 times)

Sibley

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Replacing register & return air vent covers
« on: July 09, 2017, 04:26:35 PM »
All the register covers and the return air vent covers in my house are beat to shit. Painted, rusty & bent. Some are also broken and don't open/close. I want to replace them with new ones as I work through painting each room.

Went around measuring them, and I have 7 different sizes for the registers and 3 for the returns, at least from the outside. Can I work on standardizing these, at least some? House was built in 1919, so the vents and ducts were probably added in a retrofit.

Also, I've got 2 return air vents in the living room that someone had sealed half of, so I'll need to get smaller covers for them. They're about 2.5 feet long currently, and the open length is comparable to the other vents. I don't think there's an issue in terms of system functionality.

I don't know what I don't know, so would appreciate advice.
« Last Edit: July 09, 2017, 05:33:36 PM by Sibley »

lthenderson

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Re: Replacing register & return air vent covers
« Reply #1 on: July 10, 2017, 09:26:04 AM »
It would probably not want to be a project you want to deal with to resize registers and returns. It would involve tearing into walls where they are located and then you could be messing with airflow by changing line sizes in comparison to others. Just changing the flange size that your register inserts into might involve a lot of sheet metal work which can be really difficult to do in the confines of a stud cavity.

Just guessing, but if you are measuring the outside dimensions, you may not be getting a true sense of how many sizes you are dealing with. In other words, they can be for the same sized duct but have different flange lengths and thus giving you different outside dimensions. The best way to know is to remove the register cover and measure the the duct opening and buy the appropriately sized register for that duct opening.

Sibley

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Re: Replacing register & return air vent covers
« Reply #2 on: July 10, 2017, 09:48:14 AM »
That makes sense. I am measuring outside dimensions. I will take the covers off and re-measure, and hopefully get a little more consistency. Thanks!

roastbeefbandit

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Re: Replacing register & return air vent covers
« Reply #3 on: July 11, 2017, 08:55:14 AM »
If you're happy with the way the AC functions, and this is mostly an aesthetic project, avoid standardizing the sizes. If you post some pictures I can give you some suggestions.

Sibley

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Re: Replacing register & return air vent covers
« Reply #4 on: July 11, 2017, 09:36:16 AM »
Well, we're not going to say that the upstairs is cool, but that probably has something to do with the 2 of 4 vents that the covers don't work right....

I'm not going to mess with the stuff inside the wall. If I need to get 13 different sizes, then I will. Hopefully once I measure the actual vent/duct/whatever it's called, they'll be all the same and it'll be easier to buy new ones.

On the other hand, my family can't complain that they don't know what to get me for Christmas/birthday! I've been putting lower priority stuff on my wish list :)

Dee18

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Re: Replacing register & return air vent covers
« Reply #5 on: July 11, 2017, 11:42:23 AM »
For the ones that are not bent, spray paint them with metallic paint.  I had a very old house with awful looking registers, some of which were unusual sizes.  Once painted they looked brand new.  The difference was amazing.

Sibley

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Re: Replacing register & return air vent covers
« Reply #6 on: July 11, 2017, 12:51:02 PM »
For the ones that are not bent, spray paint them with metallic paint.  I had a very old house with awful looking registers, some of which were unusual sizes.  Once painted they looked brand new.  The difference was amazing.

I'm actually not sure if there are any that aren't bent that are working properly. I'll look at them when I take them off to measure, if I can clean any of them up I will. It appears that registers are expensive.

dragoncar

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Re: Replacing register & return air vent covers
« Reply #7 on: July 13, 2017, 07:55:47 PM »
I just replaced a bunch of mine -- they are not particularly expensive and I'm lucky that mine matched standard sizes.  You can bring your old registers to home depot and match them to ones the sell.

El_Viajero

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Re: Replacing register & return air vent covers
« Reply #8 on: July 14, 2017, 11:34:08 AM »
I write educational materials and marketing communication stuff for an HVAC and home performance company. I'm not an HVAC pro myself, but I'm comfortable saying I know more than the average person.

For starters, don't do anything to reduce airflow. Painting old registers and grilles is not a good idea since many old ones already have grille fins that are relatively close together compared to what's out there nowadays. It's better to get new "high velocity" or "high flow" grilles.

Since you're working on it anyway, consider adding a return to your system. Most houses don't get enough return air. Adding a return reduces static pressure, makes the system quieter, and can help your equipment last longer. This is actually pretty easy if you've got a central return/trunk line with metal ductwork. You just cut into your wall somewhere along the trunk line. After the hole is there, use a shop vac to suck the dust and metal shavings out of the ductwork before it gets to the air handler/furnace or hits a filter.

Check to see if your returns actually have ductwork right behind them or if the duct just opens into a wall cavity. You want the duct to only be pulling air from the living space, not from inside your walls where there's fiberglass and so forth. This was the case in my house, and it's apparently pretty common. The return on the second floor was actually just a hole in the bottom of a hall closet with a louvered door. It was sucking air not only from inside the wall, but also from the attic! There was a toilet vent pipe inside the same wall cavity that ran all the way into my attic through a big hole. The return was sucking attic air through that gap. I've since sealed up my attic and built a "duct" around the upstairs return using Hardcast 1402 mastic tape and insulated flexible foam.

Sibley

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Re: Replacing register & return air vent covers
« Reply #9 on: July 14, 2017, 09:03:28 PM »
Thanks El Viajero.

There are at least 6 returns in the house, it's just under 1500 sq w/2 floors. I believe that the returns do have duct work, but will confirm that when I measure. And I'd be shocked if there was insulation in the walls!

I plan to get covers (or whatever they're called) that suit the style of the house - 1919 w/a lot of the original detailing. I expect those to be more expensive than the basic ones, and I'm ok with that.

There is a return vent in the utility room on the box-ey thing that attaches to the furnace. It's about 6 inches from the furnace. My home inspector said that it should be sealed - does that sound right? I understand that there needs to be access to that area, but right now it's got a grill.  I could make it solid if that's better.

El_Viajero

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Re: Replacing register & return air vent covers
« Reply #10 on: July 15, 2017, 08:18:56 AM »
There is a return vent in the utility room on the box-ey thing that attaches to the furnace. It's about 6 inches from the furnace. My home inspector said that it should be sealed - does that sound right? I understand that there needs to be access to that area, but right now it's got a grill.  I could make it solid if that's better.

The boxey thing is probably your return plenum. Is it a metal box into which all the return air enters before being pulled into the furnace? If so, that's your plenum.

If you're saying that there's a return vent on the plenum itself, that seems weird to me. Does the vent open into your living space or just pull air from the utility closet?

You should always seal your ductwork, including the plenums, with mastic tape (Hardcast 1402 is top notch; cheapo hardware store foil tape falls off) or actual mastic. You should also seal the connections around vents, caulk around return grilles, etc. as a best practice. So if that's what your inspector meant by "sealing," then yes.

Sealing supply ductwork is important for energy savings and comfort (i.e. even distribution of air among rooms); sealing return ductwork is important for indoor air quality. If you've got your system in an interior utility closet, it's not such a big deal. It is a big deal for those of us with furnaces in our crawlspaces or attics. You don't want the system to circulate air from those places.

Sibley

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Re: Replacing register & return air vent covers
« Reply #11 on: July 15, 2017, 12:06:50 PM »
Yes, the return air enters this, so it is the plenum. It's in the utility room, which is at the back of the house and there's free air movement between the utility room and the rest of the house. Furnace/hot water heater are not behind walls/doors. The utility room was filthy when I bought the house, that's been fixed, and I also got the ducts cleaned. So the system is a lot cleaner overall now.

I will cover the hole in the plenum somehow. Either with this tape, or maybe there's a solid plate I can get and put on instead of the grate.

El_Viajero

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Re: Replacing register & return air vent covers
« Reply #12 on: July 16, 2017, 11:13:38 AM »
Yes, the return air enters this, so it is the plenum. It's in the utility room, which is at the back of the house and there's free air movement between the utility room and the rest of the house. Furnace/hot water heater are not behind walls/doors. The utility room was filthy when I bought the house, that's been fixed, and I also got the ducts cleaned. So the system is a lot cleaner overall now.

I will cover the hole in the plenum somehow. Either with this tape, or maybe there's a solid plate I can get and put on instead of the grate.

So you might want to ask a real HVAC professional about this not a "fake" pro like me :-). It sounds weird that they made a vent right off the plenum, but maybe there was a reason. Maybe they needed to feed the system more return air because of pressure imbalances or something. If that's the case, it would be better to add a return to the living space, but having one right off the plenum could be better than nothing... especially if the alternative is high static pressure and noisy vents. Again, I'd consult a pro.

Sibley

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Re: Replacing register & return air vent covers
« Reply #13 on: July 16, 2017, 12:22:01 PM »
Yes, the return air enters this, so it is the plenum. It's in the utility room, which is at the back of the house and there's free air movement between the utility room and the rest of the house. Furnace/hot water heater are not behind walls/doors. The utility room was filthy when I bought the house, that's been fixed, and I also got the ducts cleaned. So the system is a lot cleaner overall now.

I will cover the hole in the plenum somehow. Either with this tape, or maybe there's a solid plate I can get and put on instead of the grate.

So you might want to ask a real HVAC professional about this not a "fake" pro like me :-). It sounds weird that they made a vent right off the plenum, but maybe there was a reason. Maybe they needed to feed the system more return air because of pressure imbalances or something. If that's the case, it would be better to add a return to the living space, but having one right off the plenum could be better than nothing... especially if the alternative is high static pressure and noisy vents. Again, I'd consult a pro.

The house was built in 1919, and there has been quite a bit of DIY, not quite great pro work, and the usual oddities expected from such an old house. I wouldn't bet on there being a reason.