I recently installed a Venmar Eko 1.5 HRV in my new home. I'm wondering if anyone could give any guidance on how to program it for optimum efficiency? I just turned it on, and placed it into 'Smart Mode' for now. I live in Charlton, MA which is 10 min from Worcester. It's a 2 level, 3 bath. 1st level is a concrete radiant floor set at 68°, 2nd level has no heat, but its only about 4° cooler.

There are 4 'intakes, 1 in each bathroom, then 1 in the laundry room. Then there are 4 'exhausts', 1 in each bedroom and 1 in great room.

I was hoping the HRV would help transfer some of the heat upstairs, or in general keep the heat into the house more so the radiant doesn't kick on as much. There seems to be a full set of programming methods. It has 3 modes, SMART, Recirculation and Vent. Every day you can set one of the modes up in 4 timeslots, like morning, day, evening, night. So I'm not sure where to begin?

It seems like I wouldn't want to bring fresh air in during the coldest times of the day, especially in the winter, but I'd want to try and recirculate the air in the house allot to try to move around the heat? I'm not sure... any help would be much appreciated.

Thanks,
Ryan

Ryan,

Lots of us have HRV's and don't know exactly what to do with them. I have the same model that you have. I am in a different location from you, so probably have different objectives. My objectives are the following:

- vent the conditioned crawl space to make sure that it does not get humid (need to add humidity sensors there, but in this very dry climate, it does not seem like a severe problem). The builder normally uses a continuously running 80 CFM exhaust fan for this purpose, but I thought I would like to recapture some heat in the process.
- mix the air to try to distribute some of the passive solar gain to the rest of the house during heating season
- get rid of any smells from cooking or bathroom odor, although each of these areas has their own vent fans with efficient ECM motors
- vent excess humidity from the house, but in winter time I have added a humidifier to try to get the humidity sensor to get off LL% (meaning "off scale," too low to read) or stuck at 20% which means 20% or lower, but still above the LL%
- vent CO2 from human breathing, but I need to add a CO2 sensor to help guide control of the HRV for this purpose

I most often run mine at 20 minutes of fresh air exchange, and 40 minutes of recirculation. I especially like the recirulation to redistribute the passive solar heat gain during the day. Sometiimes on cold nights I cut mine off completely. I really need to add more sensors before I can do more intelligent control of the HRV. I expect that humidity control may be more important in your area than in mine.

Lee,
Thanks that's helpful. Basically I'm looking for the same thing you are. I have the radiant floor being driven by a tankless electric water heater. My bill in MA last month as about $450 for electric! I believe $375 of that was just for the radiant, which doesn't make sense. But my house is also a Passive Solar design. There are 40ft of sliding glass doors on the South side of the home. I get good sunlight on the floor during the day, but I probably need to cut down a few trees. I was hoping the HRV could recircluate the air as well, especially to the upstairs where there is no heat. Right now it's about 4-5 degrees cooler.

So I'll try what you said and program it so its mainly re-circulating the air during the day and maybe cut off the venting at night.

When you do the air exchange, is that the 'VENT' mode? I'm confused by the different modes.

Thanks
Ryan

Ryan-

$450 for electric. Gulp! I am not a fan of using electricity for heating when the quantities are that high. I would think that a water heater fueled by natural gas (if it is available) or fuel oil (that seems to be available almost everywhere in New England) would reduce your heating costs by about a factor of 3. The factor of 3 corresponds approximately to the fact that you have to burn about 3 times as much fuel energy as the electrical energy provided at the house due to generation and transmission losses. I just got my natural gas bill in the mail a few minutes ago, and it was $35.87 for the last month (Nov. 16 to Dec. 16), and we have over 7000 heating degree days over the winter. My electric bill is always $7.45 since I generate more electricity than I use. (The solar domestic hot water system also helps reduce the natural gas bill.)

I may have mislead you about my house design here, as my "prime" heat source is a natural-gas fired hot-air furnace, with the passive solar adding in some heat (~40% of total heat requirement), as well as applicance use (~20%). The solar gain is strongest on the south end of the house (with the long axis of the house being north-south), and the HRV helps to distribute that heat, but I still see about 5 F differential between highest and lowest temps in the house on a sunny winter day.

Yes, the "Vent" mode on the Venmar HRV provides fresh air venting either full time at maximum rate, full time at minimum rate, 40 minutes at minimum rate, or 20 minutes at minimum rate, all selectable by using the up-down arrow keys. For the 40- and 20-minute cycles, the system recirculates air the balance of the time (when it is not venting), and the recirculation sounds as it it is at maximum fan speed for one of the fans while the other fan is presumably off. My power measurements don't exactly correspond with this explanation, being 26.1 W at minimum, 70 W at maximum, and 57.4 W while recirculating, so maybe I am guessing wrong. It is possible that the system is using the 57.4 W - (70 W/2) = 22.4 W just to hold the damper door closed to recirculate the air. (The minimum speed is selectable during setup on the HRV unit as one of three speeds, and mine is on the lowest.) In the "Recirculation" mode, it runs the one fan at maximum speed continuously. In the "Program" mode, it should be possible to mix and match from the above options. There is nothing particularly smart about the "Smart" mode, so you should feel empowered to set it up the way you want it. The above description is my guess at how the system works; you could also see what you can glean from the manual, although it is not great.

Sounds like you might have a lot of air infiltration around your sliding doors. You might consider an energy audit including a blower door test to see if that might be a contributor to your high bills.

Good luck,
Lee