Air Exchanger - No HVAC advice, please

shawnnixon1

I have a 2 story home and basement. Rooms are upstairs. I’m installing an HRV and the technician said I will have one register vent upstairs bringing in fresh air, Main floor will have one bringing in fresh air and the basement will pull stale air out.

is this a good method? We are trying to do this without breaking walls and this would be the only way.  Will running an hrv like this eventually ventilate the home and remove excess co2? I have no HVAC system and this will be dedicated ducts for air exchanger

shawnnixon1

Hi I’m buying a new ERV and cannot decide between the Lifebreath 170ERV 160cfm vs Venmar A160E65RT

Venmar has the virtuo technology which self balances and always balances itself if the pressure changes due to clogged filter or whatever the case to my understanding. It also comes with MERV8 and upgrade option to Merv 13 filter but I prefer to keep it merv8 for better airflow

Lifebreath has higher CFM but MERV 6 filter which I dont think is very good? Upgrade option to merv 13 but im assuming this will slowdown airflow by alot?

my house is 1800sqft with basement of 400-500sq ft or so and heating is baseboard so dont have hvac. I currently have a super old venmar pro200 in attic and its useless doesnt remove the high co2 in home

shawnnixon1

I also saw ALDES but never heard of this company

Jamie Hall

Before we comment at all, let's step back for a moment.

First, what, exactly, are you trying to do? If it is to provide adequate air changes per hour while conserving energy, that is what HRVs and ERVs both can do. However, if you are also trying to improve air quality, keep in mind that HRVs do that by bringing in fresh outside air. ERVs don't: while they do bring in outside air, they can and do recycle many of the airborne contaminants, as they gain their higher efficiency by basically recycling the moisture in the air -- and many of the contaminants are recycled in the process.

I am a bit concerned about your comment about "high CO2" (carbon dioxide). If it really is CO2, that indicates simply that you need much more outside air exchange. CO2 is a perfectly natural result of the people (and any animals) living in the space, plus such appliances as unvented gas stoves. While it is relatively harmless in reasonable concentrations, if it is high it does indicate inadequate air exchange. If, however you actually mean "high CO" (carbon MONoxide) that is a major problem, and you need to locate the sources (combustion) and eliminate them by providing them their own venting. High level CO concentrations will kill you. Low level concentrations, however, will simply make you chronically ill -- and you may not realise what it is that is happening.

shawnnixon1

Hi thanks for the reply and I meant CO2 not CO its at around 1100-1300 and I need that to come down to 450-500. 

So you are saying an HRV brings in more fresh air than ERV? My home in winter is very dry and causes skin irritations and summer I have AC on all the time which is why I preferred ERV as it will take the moisture out in summer but recycle it in winter but my main concern is fresh air to get rid of the excess co2….but Im confused which of the 2 to go with and my sq ftt of my house what is a good cfm rating I should go with

Jamie Hall

If it were mine to play with, I'd go with an HRV -- not ERV -- and a humidifier. I happen to like fresh air, so I'd want around 500 cfm, which will give you two air changes per hour. ASHRAE recommends a good deal less than that -- 0.4 air changes per hour -- so around 100 cfm would meet their minimum standard for air changes.

shawnnixon1

So i dont havw an HVAC system i have baseboard heating, does this dry indoor air? How would I get 500cfm with an air exchanger

GGross

500 CFM would be a fairly large HRV, for reference I only stock up to a 250 CFM model at our HVAC wholesale outfit in a rural area. I am with Jamie that I think more fresh air is better, but you may want to check out what the budget can stomach. There is always the option to add a second HRV later if you opt for a smaller one now.

And I do believe the humidifier is recommended because cold winter air tends to be more dry, at least in my climate zone it is

GGross

As far as brands go Venmar seems to be a good name if you are located in Canada. Here in the states they will sell units but will not sell any parts to us for some reason. If you are in the US I would recommend Broan as they are somehow linked up with Venmar and practically identical units

Jamie Hall

No form of heating dries air more than any other. What dries air is warming it. If you have radiators you can just stick a pan of water on each one...

shawnnixon1

Why would i add an HRV if i have dry winter? Would I be better with ERV that keeps moisture in and summer is ac so keeps moisture out

Jamie Hall

The problem with an ERV is very simple. In addition to keeping the water in, it will also recycle any contaminants in the air which can get into the water. Many gasses and odours, for instance, as well as some of the mold and other nuisances.

shawnnixon1

Makes sense none if the hvac contractors told me this they all said u shud get erv because hrv will dry out the house so how would I run it in summer since my wall ac thermopump will be running while hrv bringing in humid air? Co2 is high at home i need the air exchanger to run 24/7

shawnnixon1

Looking at Lifebreath 267cfm hrv for a 1900sq ft house will this be loud?

shawnnixon1

Lifebreath MAX 267 vs Fantech Hero 250hec

Hello everyone

My home is a 2 story cottage + basement with baseboard heating in Montreal Quebec. My co2 levels are 1100-1300 and need to bring it down to 450-500. My old air exchanger is in the attic which is useless. A professional is going to install an HRV in my basement where it will suck in stale air in basement and push fresh air on main floor and too floor.

Home sqft is 1800 without basement, basement has 14x21 room and another room 12x10.

I read that oversizing the HRV and running it at low speed is good and decided with these 2 HRV

Lifebreath Max 267: 267CFM
Fantech Hero 250h: 263CFM

I would of went with Lifebreath but after seeing the specs it seems the Lifebreath comes with Merv 6 filters and option to upgrade to Merv 13 where Fantech comes with Merv 8 and option to upgrade to Merv 13 or HEPA. I know this will reduce CFM but thats why I thought if I oversize it doesnt matter?

1. Is it overkill?
2. Will it be noisy at the registers/vents where its pushing air?
3. Should I go with Fantech because HEPA is an option?

EBEBRATT-Ed

No It doesn't sound like that will work but I admit to not being clear about what your doing. An HRV needs to be ducted to outside the house with 2 ducts. 1 to bring in fresh air and one to exhaust stale air. Using basement air is usually not a good idea.

If you don't go through an outside wall or roof I don't see where your getting fresh air

shawnnixon1

There will be fresh air coming from outside and one stale air going outside, but fresh air/recirculating will be one vent on the top floor where the bedrooms are then the samething on main floor. Basement will pull stale air to outside.

Can you explain why using basement to pull stale air is a bad idea? 

mattmia2

You should put in some floor registers or something and pull the air from there. Relying on there being a path for exhaust air to the basement is a bad idea.

shawnnixon1

Here is a picture exactly how it will be, I cant put floor registers because I wont be breaking opening the walls. Currently there is a duct going from roof to basement and the rest will be made through walk in closet upstairs to laudry downstairs to basement right under all 3 on top of each other to pass the ducts.

clammy

First off where is the high co2 coming from your heating boiler ? Has your boiler venting system been check ? Does your heating system have a combustion make up system or is it just pulling air from the basement ? Unless your home is extremely tight and the build up is just from people breathing I would be looking as to why the co2 is so high and not just selling you a Hrv system . Personally I would never pull any air from a basement unless transfer grill where installed either through the basement door or floor , so that there’s no chance off possibly pulling combustion products or creating a negative pressure . Also I thought that most hrv are not supposed to be installed in any area which will see anything close to freezing due to possible damage to the heat exchanger ,but I could be wrong and may well be , also remember that when it’s running it may increase your your heat lose in the winter and possibly higher rh in the summer aside from increased cooling load and that additional damper may be needed to stop migration and excessive condensation from forming in the fresh air inlet piping ,this detail may or may not be included in the installation instruction ,due diligence in your research will be required on your behalf ,a educated consumer always does better then hoping your getting the right contractor and he’s not full of it ,there always a lot of that happening these days . Personally I would be concerned about high co2 levels and where and what I should causing it and if it’s just humans and a tight home then ok . From the small amount of research I ve done and from personal use of the ventilation fans and there accessories for both Erv s and hrv I liked what I saw from Fantech seemed they had just about everything a erv or hrv system could need including timers and co2 room sensors but it always makes senses to let the installer recommend what there used to using so they can’t pull a we never installed one deal . Do your research and don’t just hope the guys correct and not pulling your chain for a sale . Also all duct work should have all joints sealed and all duct work insulated which one would hope .
Peace and good luck clammy

pecmsg

I doubt that HRV fan can handle the static pressure of all that flex duct!

Jamie Hall

Two problems. First, you are counting on air circulation in the house to bring air down to the HrV return. Unless you have an exceptionally open plan -- including the basement -- that is problematic. There will be relatively much less air from the second floor going to return. Second, there will be much less air going to the second floor through the feed ducts, unless they one going up there is much bigger than the one going to the first floor.

Very difficult to balance.

pecmsg

HRV, Who says you need one and why?

Jamie Hall

The other thread the OP put up has something about high carbon dioxide levels -- which suggests that he has, overall, very poor indoor air quality for some reason.

It would be more interesting to find out why the indoor air quality is so bad and fix that...

mattmia2

Remember for air to get in to a room other air has to be able to get out of the room.

jumper

Is your house leaky or tight? Are you trying to save energy or control humidity?

shawnnixon1

Thanks for the advice, i have a hot water tank in basement I put in a carbon monoxide monitor and shows 0….I did a test i opened all windows and co2 dropped to 520 and we left home came back 4 hours later it was still around 520. After us sitting at home for 1.5 hour it increased to 900

shawnnixon1

The indoor quality is bad because I have no ventilation

Jamie Hall

duplicate thread

But what I think we may be seeing here is a textbook example of the too tight house. Or building. I've seen them before -- before most of you were born, perhaps, during the Carter/Arab oil embargo. People went around removing all the ventilation they could in the name of saving energy, and the results were pretty horrible.

Same song, different band.

A properly ducted and installed HRV system, capable of at least 2 air changes per hour, will solve the air quality problem. It will increase energy use, no question. But not as much as opening a window. However, it will have to be properly ducted, like any other HVAC system. Adequately sized ducting, and both supply and return registers in each space. Can't avoid that.

EdTheHeaterMan

shawnnixon1 said:

The indoor quality is bad because I have no ventilation

What ever you select ERV or HRV, make sure it is installed by someone with at lest a half of a brain. Unlike me!

Jamie Hall

This may be a silly question, but why two threads on the same topic?

EdTheHeaterMan

Jamie Hall said:

This may be a silly question, but why two threads on the same topic?

There were 4 at one time. Now it is down to 3. @Erin Holohan Haskell must have combined one away.

One of the threads had zero responses for over 20 hours. That can be frustrating if you are looking for answers NOW!

Asking the same question 4 different ways did finally get some good responses though. And at least one not so helpful response from me.

Erin Holohan Haskell

I've combined the duplicate threads into one here. Thanks.

EdTheHeaterMan

Erin Holohan Haskell said:

I've combined the duplicate threads into one here. Thanks.

so he started another one. https://forum.heatinghelp.com/discussion/189928/10cfm-vs-10-sre

Erin Holohan Haskell

@shawnnixon1, please keep all of your comments related to this issue on this thread and do not create new posts. It causes confusion. Thanks.

Here are some tips for using the forum: https://heatinghelp.com/forum-user-manual