Spot ERV/HRV Side Effects: Why I Avoid Lunos, Ephoca, or Panasonic All-In-One Ventilation 

Thanks so much Corbett! I really appreciate you discussing my DIY HRV. Not only that, but this video was full of invaluable information on which systems to avoid. Love it, as usual.

I appreciate this video and validates some of my suspicions about the efficacy of these units. What is a better option for retrofitting an ERV? I have a new builder-grade home that is very tight and the air quality in the kitchen literally stinks. I considered a spot ERV like this because the only way I can install a ducted ERV is by running insulted lines through my unconditioned attic (I've heard this is a no-no).

Your mic is on point! I’m gonna applaud you for that. You got like ASMR podcast thing going on.

Interesting, a real buyer beware and informed situation.

Thanks Corbett for the amazing video.

This is a good video and I’d be interested to see a smoke test done considering how close the inlet and outlet is.

Thank you!!! I live in an old house and I was trying to get better air quality and run into this products I was like I need it! But I had the same question how I am sure they don’t feeds in the stale air if ducts are next to each other. What are the options for a retrofit house

I agree they are not so good value for the money compared to the ducted ones. They are convenient for small retrofit projects though , a lot of European apartments were built without ducting in mind, my own included. I have installed a pair of those in my 2 room flat and they definitely work, admittedly not even close to a ducted system.

Hey Corbett. Remember me? I bought 32 lunos fans for my project! The bath fan was always an issue in my case - I specced fan timers to mitigate pressure issues - but the more pressing concern is adequate dilution air since we are about 2.0 ACH. We are giving each homeowner an Aranet-4 Co2 sensor to help them figure out how high to run the Lunos system. Looking forward to sharing if the system can keep up with the occupants.

Many people can't use ductless system due to old brick building, concrete block building without attic space (specialty in warmer climate like south america, india and africa) house usually have a split system there for cooling.. would greatly appreciate your recommendation for places like this? Any particular system & brand you would choose overalls.

Thanks for your video. I am currently building a tiny house with 300 sqft / 2 people living in it in the Northwest / Idaho. What ERV system would you recommend installing? Thank you

I gave Alex a follow. I'll watch his video shortly.

Interesting video. I'm about to build a studio in my garage, hopefully sound proof as I'm going for double stud, room in a room. The room will only be 6m x 3m x 2.5, but will house my vinyl collection etc. My concern is heat and humidity of the summer months here in Brisbane. Would these All-In-One Ventilation be ok the a small room, the single is called mono here? I was planning on connecting my house ducted AC, adding an inflow for fresh air and then EVC for heat/humidty control, but might be overkill? \

The Lunos can recover moisture in cold weather when the incoming air is below the dewpoint of the outgoing air. Moisture in the outgoing air condenses on the core as it warms, the evaporates into the dry incoming air as it cools. I don’t believe it’s as efficient as an ERV, but it’s much better than nothing (a la HRV). Regarding balancing, if you put a pair in the same air space you don’t have to worry about pressure zones messing with balanced airflow, but this gets spendy real fast depending on how many zones you need ventilated. I agree with all the negatives, especially price. If designing a house from scratch there’s no excuse to use these over a ducted system.

Thank you for the explanation and video. Looking at the spec sheet values and relating them to real-world advantages and disadvantages is great. Is it possible that the all-in-one products are targeted at condo and apartment applications where there isn't an option for ducting?

Hi Corbett, I have a situation where someone built two small offices ( without a permit🙈) inside a dusty warehouse at a lumber yard . The contractor installed a mini split for each office. The problem is the girls who work in there can’t breath well….Can one of those “single hole” through the wall systems be used?…..I am thinking to install a extension duct , up through the roof of the warehouse for the intake and exhaust air….it might run 8-10 feet, and I can use some mastic to seal around the connection. (Each space is 200 square feet) What do you think? Is there a better solution? I am just trying to keep the girls in the office form getting sick form the lack of ventilation… etc, they are dealing with stale warehouse air,and musty dustiness….(I dont want to waste mony on something that wont work) The other alternative is a stand- alone air purifier perhaps… Please help, thanks in advance

Thanks for the overview! Those switching Lunos fans seem like junk for the price! On the Ephoca systems, a couple of comments: #1: For the short cycling intake vs. exhaust, intuitively I would agree that this could be an issue. However it seems like this is just your word vs theirs. Or did you smoke test it to see if it short cycles? #2: Just because it is an all-in-one solution does not mean it is inherently bad. It really depends on the application. For a tiny home or ADU, these are pretty great! On a project I am working on we are only required 30cfm of ventilation air. By using the unit for ventilation, we get rid of the need for additional exterior louver, 15-20ft of GSM duct, soffiting and supply register. Time and materials for this completely justifies the additional cost of the internal ERV. It is for sure limited to small homes or ADUs because it can only achieve 40cfm.

Thanks, again Corbett for great content! I am a GC and High School Construction Tech teacher. We are building our first tiny house on wheels and I have been following you guys from when you built the Tiny Lab. Would you still recommend using the Panasonic unit installed like you guys did? We are building a 16' with sleeping loft. I would love your input because we are planning to use this as a building science teaching platform for our community. Thx.

I’m renovating and extending my home in the U.K. and want to install a system to change the air in the house, but due to ceilings height, cannot fit a ducted system. What are my options if not the decentralised units?

Thanks for the video I’m buying a 1300 sq ft, 2 level home in the Yucatán, Mexico. I want to 1.). be able to ‘turn over’ the air in the house so I don’t have to keep windows, etc, open. And, 2) demumidify the air since this is the tropics. The house will also have mini splits for cooling and 3.) I would want to filter the incoming air for allergens/pollens Can you give me an idea at what I might want to look at? Many thanks 😎. 🇲🇽

What do you think of the optional fresh air intake for Santa Fe Ultra dehumidifiers? They lack the energy saving feature of ERVs but if already needing a dehumidifier they can dehumidify fresh air that is brought in through a merv 13 filter, and in the winter can run on fan only mode to keep bringing in fresh filtered air. Of course they cost more than a broan or panasonic ERV so wouldn't make sense if not already needing a dehumidifier, and they could also pair well together, or pair a Santa Fe with a DIY HRV.

Re zhender-aside from the obvious-price- and inability to imbalance -ie establish positive pressure, and as you have demonstrated, non negative pressures in the house as it’s impossible to generate really high pressures in American homes- any other issue you ha with zhender? Thanks

Wow from England! I was looking at the Lunos E2 and found your video really interesting. You see we live in a granite longhouse in the middle of a damp National Park called Dartmoor. We are in the process of insulating the house and have an airsource heat pump which works great in the part of the house that is insulated. However even before the insulation we had a humidity, and therefore a mould, issue and I'm concerned that with sealing us in, the problem will get worse. We are not going for passive house standards but need to reduce the humidity without reducing temperature (due to the lower temperature radiators with the heat pump) - which is why we were looking at Lunos. This is a retro fit to a 700 year old house; so there's no way we can use ducting. But if these spot MVHR units have issues is there anything you would recommend as we don't want cold air blowing in but we need to remove humidity. OR would you say for our situation these could be OK. Please can you help - Steve

Hi Corbett, thanks for the vids as always!. You said at about 2m20s regarding Zehnder that you "don't recommend for other reasons". Are you able to elaborate on the reason(s), other than price? It would be a great help to those of us looking to buy a Zehnder. I'm happy to be steered in another direction. Cheers.

How do these things deal with condensation? They don't seem tilted to let gravity drain out the water. They look installed perfectly perpendicular to the wall.

I'm installing a pair of Lunos e2-60 HRVs in the small house I'm building. I was leery of a ducted system since I have an unconditioned attic and having a ducted ERV up there would be utterly pointless in the summer due to the extreme attic temperatures. A through-the-wall system has at least a fighting chance (I hope). Regarding creating an unbalanced system -- I emailed Lunos support on that topic with regards to using them as makeup air for a range hood. The claim is that the Lunos detects when the airflow is counter to the fan direction and will shut off the fan in those cases. Thus, it is literally just two (filtered) holes in the wall at that point and should be able to pull as much air as necessary. We'll see.

Sorry I might have missed this but what was your conclusion on the best way to filter and exchange air and humidity without having a system with ductwork?

I thought spot erv were for a bathroom or a kitchen. And you get a big duct type erv for whole house. I am planning on a hrv too. I need a "vent to daylight" because of masonry floor area. I plan on having a south wall planter. So plan on hanging it above the planter.

Regarding Tiny homes and IAQ, is the issue more outgassing from the building materials or from the humans and activities (cooking, etc)? I remembered you used plywood that did not contain formaldehyde for the indoor walls on the Tiny Lab.

I think the Build Equinox CERV2 looks awesome. I’d buy it if I had $6,700.

Corbet - If you were shopping for a home that wasn't brand new or custom, what age range would you suggest? It sure seems to me that a house built in 2010 is world's better than one build in the 90's. From what I've seen anything before the 70's that hasn't been remodeled needs a huge amount of work. I'm looking to buy a house soon. I'll be inspecting everything myself plus hiring a good inspector and doing some testing!

Great Video Corbett, I was interested on what your take was going to be on these Lunos systems. I know a Passive home designer that likes these and has a set in his Passive Home garage and has had issues with them. But then Again, I think he's a bit to indoctrinated with PH standards because his only ventilation is a Zehnder system and has nothing but a recirculating hood vent over his stove.

Thank you. Much appreciated. we are renovating an old farmhouse up in Quebec. I have no duct work. I’m doing a combination of baseboards. And looking into ductless heat pumps. I put a complete envelope around the house, firstly, with R4 sheeting taped. Then R 6 rigid foam insulation with built-in air barrier. That tape as well and then regular vinyl siding over that. I’m hoping the house is fairly airtight, all the windows have been changed with triple pain windows. But I’m looking for some kind of solution for ventilating and creating a balanced cost-effective way of doing it. The house has three floors. With the staircase in the middle. The inside dimensions are 32‘ x 22‘. Quite small. I will be adding an extension on the main level for a bedroom. With no basement. or upstairs. Open to suggestions. Right now the house is still mostly gutted on the inside. Just starting to run wiring and insulation and plumbing etc.. Thanks again, I really appreciate your videos Kevin

Are you talking about the Hyper Heat H2i? It goes down to -13°F. I wish they had a version for cold climates that worked down to -25°F or colder.

Do any ERV's filter up to HEPA level?

So I am understanding correctly, there aren't really any recommended solutions for retrofitting in a home without ducts? ERV/HRV or otherwise?

What if ducting is not an option? What options do you recommend?

Have you been involved in any projects using the CERV2 from BuildEquinox?

You just missed discussing the ceramic element on the lumos… did you had this pruduct in your hand? No otherwise you would talk about it

There is a brand here that sells a mini erv similar to those. However by the time you fit one for every room the cost is horrendous.

I fail to see how a pair of inlet/outlet fans alternately switching provide any sort of heat recovery as there is no exchanger?

Would have liked to see you do more research about the Lunos before claiming it doesn’t recover humidity. More research would have enlightened you to the fact that the e2-60 adjusts to pressure imbalance so theoretically the bathroom exhaust add-on would work. I installed these in my house because we couldn’t run ducting and they are working very well. Not an ERV but better than nothing. Again, maybe a bit more research since people are coming to you for expert advice. You even described the lunos components wrong. :(

When we look back 50 years or so and look at how construction and HVAC was done we laugh. It would be interesting to be able to know what our future selves will think about our current methods of construction and HVAC. Hopefully that we got it right but more than likely they will laugh and say I can’t believe they thought this or that was a good idea

Corbin, would like to discuss when convenient. I am a Building Official, Licensed Energy Advisor and Certified Passive House Consultant with some experience and testing background on these. Would like to to talk and geek out.

Why is Zehnder out of favor with you?

Look at the power requirements I believe they're 220V as it is European

Why would you want to install an ERV/HRV in the bathroom??????

As bad as these solutions are as far as filling the actual intended function of an HRV/ERV, I don’t think that the price is really a criticism. Sure, a typical ducted HRV/ERV is only $1200, but then you need another $1200 in ducting and registers. Outside of the raw material cost there is also the labor to plumb it, then to balance it. The true cost of your typical Broan system starts at $4k. I don’t really know who these systems are marketed for, but I could see that the main selling point is a low labor/cost way to meet code for mechanical ventilation with no regard to actual performance.

You would think they'd have a bath fan that integrated with their two piece HRV to provide balanced ventilation.

So then what WOULD you recommend, for Tiny homes? Which don’t have room for ductwork. Right? What are some solutions? I need to decide and order, this week! 🫣 I feel kinda like this leaves us hanging. And, where’s that video you’d done on why you’d recommend ERVs? (Why wouldn’t you want an HRV, to preserve heat? Especially in a cold climate. I mean, you may as well just open a window w/o having the heat recovery aspect! Right? 🫠) And, why can’t there be a unit that does BOTH? Deal with heat *and* humidity! 🤷🏻‍♀️