HRV/ERV options

Specific Inspection Topics Inspecting HVAC Systems
1

Need a little help finding the right Heat Recovery Ventilator. I am planning to install a fresh air (hrv) system- the unit will supply fresh air to the basement of my 1500 sq. ft. ranch with two supply registers and the return will be tapped into my main furnace return. I would like to get some fresh air into the basement as we spend some time down there. My HVAC guy only has a few options- I am in SE WI.

  1. I have seen the Broan HRV90S or the fantech 70 -100 as the most easy to get. There is a company called renewaire and Vanee but I do not see pricing- thoughts?
  2. Do any of the HRV systems come with an option to augment the supply temperature with an electric in-line heater and maybe a VFD motor which could be controlled by a thermostat?

Thanks for any Good information.

2

Anthony,

I would think more towards the RenewAire ERV as it doesn’t remove humidity as an HRV would. The last thing you would want to do is make your home environment more dry than it already would be in any Wisconsin winter.

You won’t need a huge unit and I would recommend dumping the fresh air in far away from the furnace to allow it to mix with the rest of the return air and be tempered prior to going through the furnace.
If you want to bring in the fresh air directly to a room, a stairwell is a good area as you don’t spend time there.

3

Thanks for the response Scott.
My plan is to “dump” the fresh air into the basement (2 corner rooms- no doors) and pull exhaust from the main return and the upstairs creating a cycle of air and positive pressure in the basement. I found a great website with multiple manufacturer’s and prices listed- see below. They also have an in-line duct heater with a thermostat so I can augment the cold winter air and make a zone in the basement with a thermostat that ties to the duct heater. Given my climate and the fact that my house has natural high humidity I went with an HRV. I went with the fantech flex100H and NEP Therm duct heater. 2.0 Kw heating element, it comes with the T-stat. $630 for the HRV and $240 for the heater- about $900 with shipping total. I am going to try to reduce my dehumidifier use and try to turn my radon fan off to try and offset the operational costs of this unit. I have done radon tests before and during operation of my radon fan, I will see what the HRV and this set up does for radon, humidity and general comfort level of the basement. I’ll post my results in a condensed email as I get this unit installed. below is the web site I found.

http://www.hvacquick.com/products/residential/HRVs-and-ERVs/Residential-HRV-ERV

4

Thanks for the update Anthony!
Will check in here to see your progress.

5

OK- quick and short to a long process! Installed the HRV and in-line heater with thermostat creating a basement “Zone”. (total cost maybe $1200)
-Turned off my radon fan and performed test- 33PcI/L
-HRV Low setting- 9 PcI/L
-HRV High setting- 7PcI/L

  • Temperatures have been cold 10-30 degrees, no condensation on my windows; I attached a watt meter to the heater @ 68 degrees costs about $1.25 to maintain for the day in high.
    I was looking at my install and decided to try something a little different:
  • Moved the HRV exhaust from the exterior wall fitting to the Sealed sump pump directly below the unit. Creating “Sub-slab Pressurization” high setting, no Radon fan - 2PcI/L!
  • Waiting to check low setting as my tester is at a home inspection.
    Very Happy with this- I will be eliminating my Radon fan use and have stopped using my dehumidifier.
6

Not worried about radon entering the HVR and backing into the home during power or system failures?

7

He obviously does not understand what he is doing.

8
  • Turned the HRV off and tested for radon on the main level- same level as when the HRV is on… 0.5 So, I am not too concerned!
  • I am simply trying some different scenarios given the fact that I own a radon tester, an HRV and a Radon mitigation system and everything is located in a perfect spot in my utility area of my basement.
  • I can easily move the ducts around and turn my radon system back on as desired.
  • The HRV and in-line heater is working great to improve my IAQ- no more condensation on the windows.
    Have a great day!
9

http://www4.uwm.edu/radon/

http://www.tandfonline.com/doi/pdf/10.1080/1073161X.1993.10467135?needAccess=true&

When the EPA gets around to updating their outdated manuals/procedures you may have a whole new “understanding” :wink:

10

Anthony,

I would consider NOT discontinuing the use of the radon mitigation system for obvious reasons. The one that may not be obvious to you is that it is also grabbing all ( a large portion f it) of that cool, moist air that comes through your concrete through capillary suction and vapor diffusion. Water will draw up a tree 400 ft. It will go through concrete upwards of six miles, straight up. So, you are addressing this as you are also removing the vast majority of radon gases. Energy contractors are beginning to see the merits of the system for more than just radon mitigation. I have a radon mitigation system here with radiant heat. Heat drives moisture from materials. I had a 17 reading. Now down to .3 and humidity at less than 35 percent. The radon mitigation system alone has paid huge dividends in this manner. I don’t run a dehumidifier. No need.