ERV Duct Plan?
mikeysp
| Posted in General Questions on
zone 4a.
Is my ERV duct location plan acceptable?
I am installing the unit and duct work exposed in the main living space. 13’+ ceiling in main room. Drawing shows general layout.
It is a pretty good job on airtightness.
Recycled cheap ext doors and windows are probably the weak link.
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Instead of brining the fresh air feed across the house, I would bring the stale air pickup. Extend it to the bathroom and run it through the wall which will let you eliminate, or at least rarely need, the rattily bath fan. The living stale air pickup can be somewhere above the hallway at least 8' from your range.
The fresh air can be dumped just above the intake of the wallmount. This has the benefit of also conditioning the fresh air feed (less of an issue in warmer climate).
I would also add a connection to the bedroom. I find stale air pickup works pretty well there as well especially after spicy chilly night. This should be flex with a couple of bends in it to reduce sound transfer.
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Akod, I had not thought about flex duct because I’ll be running everything exposed. Any recommendation on exposed ductwork and aesthetics with flex?
The flex is only for the bedroom run, the ducting inside the living space can all be hard pipe. If you don't want flex, you can also use a duct silencer in line with hard pipe. These are not too expensive but also pretty simple to DIY out of a length of larger diameter duct, a pair of reducers and duct liner.
I don't think there is a way to make exposed flex look nice.
Great, I revamped my erv duct work:
Looks good. You'll also most likely need a duct silencer or length of flex duct on the fresh air feed. These ERV tend to be pretty quiet but the blowers still have a fair bit of airflow noise when on boost.
I highly support the ERV intakes in the bedrooms. IAQ is the next thing we're all looking at and I consider it as part of a sleep quality strategy as well, including taco night.
But we also close our bedroom doors at night for privacy, sound, and hopefully for fire protection too. So without a fresh air supply, circulation could be limited unless you undercut the doors enough. Also, consider the poor quality windows you mentioned, I'd be concerned about the erv intake and a closed door sucking outside air through the window, I can't substantiate this, its just a hunch. You'd have more experience with real world issues like this.
The wall mount miniplit is fine I guess, and it's and easier install. You already know this: nothing beats a ducted system for air distribution if you want a better performing system. Slim duct miniplits are roughly the same price as the wall mounts but it's more work on the install and commissioning. But you'll get better distributed conditioned air throughout (specifically the bedrooms), you can have actual filtration, and you can duct the erv supply directly into the return.
As for looks, Usually we're trying to hide these units, but if it's an industrial sheik (chic) thing, you can leave it exposed high on the wall or something, since the erv is being exposed as well. I personally would rather look at a slim duct unit rather than those stupid wall mounts, but that's me.
You could also paint the unit and hard duct black (or another colour I guess) as possible design thing to soften its presence and make it look more badass.
Just my thoughts,
Jamie
Thanks Jamie. I am using a wall mount because I already have it and it is a VERY good performing unit.
If it proves unsatisfactory after install, I am in a position to add an additional unit or to change out to a ducted. So I will wait and see.
If I can find a blower door guy nearby and it is economical, I would like to see what my situation looks like. If not, I may do some testing myself by sucking out air with light plastic streamers near doors/windows. I something like this on Youtube. I also have a manaometer, so I may be able to do some testing with it.
I am not sure how leaky the windows will be, I just know they are not high end. Look to be cheap plastic double hung that you would get stock at the big box store and the sale was made on price alone.
On a good note, the ERV is the Broan AI 150. It has automatic static pressure balancing; however, I am not sure how significant that will be.
The walls are OSB with all seams taped and rolled with 3m 8067 Acrylic tape; and some sealant connecting the bottom plate to the slab.
Nothing is better than free!
And being able to change it later is a good position to be in.
I'm curious to see how it goes. Especially from your experience. Please keep us updated.
Jamie
MERV 13 for stale air intake?
Does the stake air intake side also get a MERV 13 filter? Since I am trying to keep the core in tiptop shape for the life of the machine, it seems to make sense. But I wanted a sanity check.
Stale air duct sizing?
Since the ERV has 5" ports, I will run a 5" main line and branch off with 4" duct into: bathroom, main living area, 2 bedrooms. 4" Duct silencers for bedrooms.
Also, is there a specific type of intake grille I need? I thought I would buy something like these (pic) as they are only $20 for four.
Stale air intake should be picking up house air which should be clean. Most ERV have a simple washable filter for this which seems to work well enough (at least mine does). Putting a similar washable filter at each pickup doesn't hurt either as it keeps the ducts cleaner. Take a look at the filter cone here:
https://zehnderamerica.com/wp-content/uploads/2019/04/Zehnder-Diffuser-Options-04.12.2019.pdf
For mine, I use a standard grill with a piece of washable filter bent into a U shape right behind it (see attached). If you are using commercial spiral ducts, you can get a register takeoff to fit a standard rectangualr grill.
I have tried that part you linked to as a return but it clogs way too quickly, the plastic mesh just traps dirt.