Choosing ERV — Renewaire EV Premium L
tighterhouseNH
| Posted in Mechanicals on
Planning to install an ERV. Contractor is familiar with and recommends Renewaire. Looking over the ERV line, I see very good efficiency for the EV Premium L — HVI SRI of 88% at 32 F outside and 59 cfm.
I see some other interest in this unit as well on the site. Anyone have this installed, any useful feedback on this unit? thanks!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
We have an EV Premium L installed in our new home.
Keep in mind it is designed to always run at a low speed and can optionally run at a higher speed (boost mode) based on an external control, either their PBT push-button timer for a 20, 40, or 60 minute boost or their PTL percentage timer for a boost of multiples of ten percent of each hour. Both the PBT and PTL can have additional PBL point-of-user controls connected to initiate boost mode from remote locations.
(You can turn the low-speed controls to their minimum and only run the unit when called for by either the PBT or PTL control.)
There are some indoor air quality controls that can be added to the unit to trigger boost mode based on CO2 levels but from what I've heard they're quite pricey. It does not have the wide variety of controls and interfaces that is available in other brands (e.g., Zehnder). It's also not network-ready if you're into that.
If you're in a cold climate be sure your HVAC contractor knows how to correctly insulate the outside air intake duct if it passes through a basement or conditioned space, as the constant flow of outdoor cold air can cause condensation on the surface of the intake duct, especially if it's metal (which is recommended over flex duct). Our overnight temperatures have dropped into the low teens (Fahrenheit) and I've not seen any evidence of the ERV core freezing up.
I've spoken with their engineers specifically about the core in this unit. It's quite large for the rated airflow, which is why is so efficient. It does require manual balancing, but uses two ECM motors. It's likely the highest performance/dollar ratio for an ERV right now. Their white paper on defrosting with the ERV would suggest that you don't need a defrost strategy for it unless you're doing an extreme installation, like in a pool house...so it has no recirc. defrost option.
You likely will configure it at something like 75-90 CFM assuming a family of four in a typical home. Boost is easy enough to do via automation as well (simple dry contact relay on the boost terminals) for CO2 using an automation hub like Hubitat and sensors like the Ecowitt WH45, AirThings etc. You can also use a "dumb" wall mount Co2 sensor with a relay like this, which I've also used in a commercial setting connected to a larger HRV's high speed contacts: https://www.co2meters.com/Documentation/Datasheets/DS-TON-0007.pdf
That one is no longer sold unfortunately.
If you're looking to ventilate your bathrooms with this, then I'd go with the manufacturer recommended timer as it will likely be the least expensive for boost. This is also pretty trivial to do wirelessly with automation using off the shelf zigbee or zwave devices. This gives you a lot more flexibility to control on/off/boost based on feedback from IAQ sensors.
thanks @jadziedzic for the tip re insulating OA duct, I'll make sure that happens. And glad its working well for you.
@DennisWood - we do get some cold nights in S. NH so it may have to do some defrost, I'll review the docs again, I think it closes off the OA intake for some period when too cold?
I am planning on boost for showers, can use the push button timers. I have a hand held CO2 monitor. I will have to learn if boost based on CO2 will be needed. If so I should be able to go with a third party device and contact closure as you say, maybe something more networked that ends in a relay depending on whats out there. But my thought was to just do bath (and kitchen) boosts, then see how CO2 settles out.
Panasonic ERVs don't begin defrost programming until temps fall below -10 C (14 F), using an internal recirc damper. Renewaire however published this white paper on low temp operation of their ERVs. The manual for the Premium L does not mention defrost anywhere.
https://www.renewaire.com/wp-content/uploads/2022/03/MAR-LIT-165-RGB-WhitePaper-FrostControl-web.pdf
"RenewAire sticks to our frost-control policy, which states: “RenewAire’s
ERV energy exchange core performs without condensing or frosting under
normal operating conditions (defined as outside temperatures above -10°F
and inside relative humidity below 40%). "
FYI if you intend to control boost mode via an external interface (dry contact relay) Renewaire's PBT & PBL installation manuals specify (in small print) a 150-ohm resistor is to be wired in series with the connection to the ERV terminal strip with any control other than their PBT or PTL.
There is no obvious mechanism to close the OA (intake) duct internal to the unit, nor are there connections available to control an external damper (even though the installation manual does show a DAMP (damper) terminal on the unit's terminal strip; guess they left that one off ...
-- good to know about the resistor, will have to remember that! --
That white paper is interesting. At very cold temps they actually use exhaust only defrost, just shutting off the OA intake fan to warm up core. Hopefully the defrost will happen when needed!
I did find more on controls re CO2 control as discussed earlier. It looks like this is very new but they offer a BACnet gateway between a BACnet controller (BMS) and the ERV. It has several functions, one of them is to allow the BMS to control the SF and EF speeds independently.
This would allow the BMS to modulate speeds up in response to rising CO2.
I do have access to BACnet control, I assume not many homeowners would...
If the ECM motors use 0-10V control (they likely do) then you could have complete control of both fans via Zigbee or Zwave 0-10V controllers. This is how I’m controlling both exhaust/fresh air fans to ramp based on CO2/VOC/radon.
Clever!
It sounds like they do use 0 - 10 as that is how the BACnet point ranges are described. So that might be a cheaper way in, I will have to see what the BACnet gateway costs, could be anything!
I had a quick look at the ERV schematic. I've marked up the wiring with the probable connection points (easy enough to confirm with a multimeter). I'd bet some cash on being able to control these motors via 0-10V bits like the Zooz Zen54 (pic attached), or Leviton ZS057-D0Z (Zigbee). The "cheap" way to control these motors is via a potentiometer (which I believe is what Renewaire is doing across the ground/yellow wires), but you can also use a 0-10V controller which gives you 0-99 speeds to choose from. The Zooz Zen54 uses zWave wireless control. In the first pic attached, I'm showing the connections between the Zooz Zen54 and an AC infinity ECM fan. I've confirmed that this method of control works for Terrabloom, AC Infinity and Fantech ECM fans. More here if you're interested. I've been working on 0-10V automation over the last two years with a few (new) automation bits for 0-10V control to automate an HRV to respond to CO2/VOC/radon, and kitchen exhaust system that integrates via automation with the HRV to do some supply air chores.
https://community.hubitat.com/t/success-0-10-volt-control-of-ac-infinity-or-any-ec-fan-motor-using-leviton-zs057-d0z-zigbee-dimmer-or-zooz-zen54-zwave-0-10v-dimmer/104450
Using two of these Zen54 (or Leviton ZS057-DOZ) , an automation hub (like the Hubitat) and some code would likely allow you set up multiple balanced air flows (or constant ramping) to run this unit based on feedback from an IAQ sensor. In my case, I'm using 50,60,75,90,100 and 110 CFM balanced profiles. If they are allowing Bacnet integration, it's almost certainly via 0-10V control. Would be interesting to find out!
I see, pretty nice. I do have access to hvac controls with 0 - 10 VDC outputs so I could do co2 control this way. I will look at some of these devices also in a little more detail when I have a little time.
So I've heard pretty encouraging words about the Renewaire EV Premium L, anyone else using this or similar Renewaire?
Yes, have installed Renewaire ERV’s for many years. Zero issues, great results. Yes OA ducts should be insulated R8 and should be poly exterior not foil. We also seal the exterior poly (mastic it to the rim joist or gable wall if in sealed attic assemble (conditioned) to ensure no air intrudes under it. If a duct lining should be pierced at some point condensation will result from OA and IA mixing. Have seen more than one system that was not airtight and ended up full of condensation and mold. Use exhaust fans for bulk moisture/steam and greasy kitchen exhaust. Keep the ERV for fresh air. Yes needs to be balanced but it’s a simple process using differential static pressure outlined in the manual. Hint - I pull the pressure taps out of housing when using the manometer and slide the tubes right into the housing. Get much more consistent measurements that way.
Mitsuman, do you have a product name for the "poly exterior" duct insulation that you could share? Much appreciated if you could!
The EV Premium series has added the ability to control a motorized damper via the addition of a fourth "DAMP" terminal to the low-voltage connection terminal strip (and an update to the internal control board). The installation manual now has a section on connecting a motorized damper to the OA ducting.
I have a EV Premium M size. It's well built. ECM fans are a must these days.
My only grips are
1. Expensive filters that are a non-standard size. Recommend installing a inline filter box that uses larger standard filters.
2. Primitive controls and lack of self/dynamic balancing. Balance will drift as filters clog. Given the price of the filters I want to run them as long as feasible which might mean having to compensate with increased fan speed sometimes. Won't be as much of an issue once I get a filter box on the inlet.
As a comparison, I installed a VanEE AI Series HRV for my father. Its balancing controls and feedback were far superior to my Renewaire. The VanEE can adapt to various ducting arrangements and compensate for the air handler fan if integrated into the central HVAC system. I was also jealous of how the CFM setpoints can be adjusted from the wall control, and that it has OA aware duty cycling (increases ventilation rates when it's economical to do so, and goes to duty cycling in extreme heat/cold).
Josh, those are all good points. If VanEE/Venmar used the larger core of the Premium L (for better efficiency) it would be a top choice in my book too. The Renewaire Premium L looks to be the same unit as these two below just sold under different brand names:
Johnson Controls - S1-TERV280
S&P USA Ventilation Systems LLC - TRe300
I wouldn't worry too much on the rebalancing during filter life spans, but I would 100% get rid of them in favour of external (larger) filter boxes after noting reductions in ECM motor wattage when using them for a given air flow. The only caveat there is that the Premium L/M provide pressure/CFM values in their balancing chart based on the presense of MERV13, or MERV8 filters which rest directly against the core. If you remove one filter only, balancing via the chart won't work correctly. That said, the core balancing values are symetrical (pressure drops are the same for supply/return with the same type filter) so you just need to make sure you remove both filters and use external filter boxes on both supply/return before rebalancing.
Then you're just looking for equal pressure drop across the core on both supply and return for the Premium L, anyway.
Of course, with any of the ECM autobalancing units, you don't need to worry about any of this with respect to filters as CFM values are determined by a lookup table referenced back to the the ECM motor current vs measured CFM. There's nothing AI about it..ha.
Josh,
The PDF shows a 10.5x10.5x1 filter. A standard 10x10 can't fit in there with a bit of foam edge seal?
I appreciate all your replies, I am learning more with each post about the premium ERV!
Can that standard 10 x 10“ filter be used, can less expensive generic filters in general be used on the renewaire premium L?
Anyone else have recommendations or issues with this ERV?
update - we're still planning on installing this one, waiting for installer to have some time. Are we still happy with the Renewaire EV Premium L? Only tip I have picked up recently is it helps quiet fan noise if the metal ducts change to flex for the last 5' or so.