Remote Living > Heating
HRV vs. ERV (or both)?
bigrockcandymountain:
I guess the question i would ask is, what problem exactly are you trying to solve with a ventilation system? Do you have higher humidity than you would like?
Is your air quality poor? What type of heat system do you have?
My experience with the 200dx may not be applicable to all ervs either. I will try to explain...
The 200dx uses an enthalpy wheel. When it is colder outside than inside, the wheel material causes the moisture in the outgoing air to condense on the wheel, make half a revolution, and then re evaporate into the incoming fresh air. This potentially transfers all of the moisture.
When there is no temperature difference, no condensation occurs, and it doesn't transfer much moisture at all.
Normal ervs use a semipermeable heat exchanger that is driven by difference in relative humidity. They can only really return half the moisture into the opposing air stream because after half is transfered, the rh is balanced and no transfer occurs. I believe this leads to less moisture transfer than an enthalpy wheel type, especially in a very cold climate.
Hrv's transfer no moisture at all.
Having both is not a bad idea, but space is limited, so i will try the hrv only and see how that works.
jlsoaz:
--- Quote from: bigrockcandymountain on January 17, 2020, 02:19:03 PM ---I guess the question i would ask is, what problem exactly are you trying to solve with a ventilation system? Do you have higher humidity than you would like?
Is your air quality poor? What type of heat system do you have?
My experience with the 200dx may not be applicable to all ervs either. I will try to explain...
The 200dx uses an enthalpy wheel. When it is colder outside than inside, the wheel material causes the moisture in the outgoing air to condense on the wheel, make half a revolution, and then re evaporate into the incoming fresh air. This potentially transfers all of the moisture.
When there is no temperature difference, no condensation occurs, and it doesn't transfer much moisture at all.
Normal ervs use a semipermeable heat exchanger that is driven by difference in relative humidity. They can only really return half the moisture into the opposing air stream because after half is transfered, the rh is balanced and no transfer occurs. I believe this leads to less moisture transfer than an enthalpy wheel type, especially in a very cold climate.
Hrv's transfer no moisture at all.
Having both is not a bad idea, but space is limited, so i will try the hrv only and see how that works.
--- End quote ---
Hi - thanks for the answers.
To answer your question, I'm trying to achieve significantly improved air quality (lower CO2) while also maintaining moderate energy usage. My home is extremely tight, and the only ventilation I really have is with a couple of bathroom fans and one or two other openings. The split-zone mitsubishi heat pump provides good efficient heat and a/c but not ventilation (unless I am misreading).
https://www.mitsubishicomfort.com/sites/default/files/manual/msz-fe18-operationmanual.pdf?fid=291
The home has no gas-burning combustion going on for cooking or heating, but the ventilation has been so inadequate that air quality has still been a concern. Recently I finally got more on top of the two bathroom fans, and according to some co2 sensors, the air quality has improved. However, this has also taxed the heating system a bit, since I am ventilating a lot of heated air to the roof. So, I'm thinking I could restore a bit of the energy-saving approach to things in the home, while at the same time bringing modern technology to bear in ventilation (rather than just cracking a window or two open and turning on the bathroom fans).
This is the type of home:
https://www.terra-dome.com/
you can see that the builder tends to recommend some ventilation/de-humidification focus:
https://www.terra-dome.com/links
https://www.thermastor.com/
so even though I'd be ok with some humidity, I'm not anxious to go in that direction if I don't have to (in addition to the fact that I am wary of what happens when it is very humid outside, which happens once in awhile).
another question comes to mind: do some ventilation systems come with the ability to interact smartly with an internal CO2 sensor and turn on and off depending on the measured indoor air quality?
jlsoaz:
I also belatedly realized another question: is an ERV or HRV supposed to be used as stand-alone heating/cooling? Or is it meant to be used in conjunction with some other heating/cooling units. I've been focusing on it for ventilation.
DamonHD:
HRVs can be stand-alone just for ventilation or can include (for example) an inline heater for when peak heat demand is very low (eg in a Passive House).
Rgds
Damon
bigrockcandymountain:
They are meant to be stand alone ventilation. They do not heat or cool at all. As damon says, an inline duct heater after the hrv can be used, but your heat pump will be much more efficient.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version