Some people seem to like the Panasonic spot ERV.
Other than that, there's nothing particularly cheap/easy. You need an appropriate space for the unit and the ductwork. It can be fairly difficult in a retrofit, maybe easier in new construction.
Thanks David. That was a very helpful response.
I think the hardest part (if you want a grade-A installation) is having a mechanical space inside the envelope for the HRV/ERV and some of the ductwork. In my own house (1930s with 9-foot ceilings and large attic) I've been puzzling over that one. I can either drop the ceiling somewhere and put the unit in there, or build an insulated enclosure around it in the attic, which is already knee-deep with insulation... 20/20 hindsight.
I have not seen any numbers on it, but my guess is that you lose a lot of efficiency with the unit and ductwork in the attic, like so many I've seen. They have the typical insulated flex running all over the place like an octopus, and I bet a lot of the heat recovery is lost.
My company is building a small art studio building later this year, and I expect to use the Panasonic unit. In a building that's mostly one room (and extremely tight) I think it will be a good idea. We are creating an indoor space for it.
Thanks for the input David. I read the specs and it says do not install in an area that might be subject to temperatures over 104 degrees. That pretty much rules out an attic. I am thinking about how to retrofit this into an existing 1970's split level.
Fantec has worked for me or as David said some like Panasonic, etc... Stick with a name brand & watch the watt per CFM #
I prefer going with standalone units run off timers - I make sure the unit can basically give me all that is required & then chop the amount needed in 1/4 to 1/3 - if they need more than that you can bump up the time it runs or the whens
As for the how & where's, well that varies depending on the situation - split level as in finished basement below, bedrooms above a great room for the main part? How much room do you have in between the floors - you can always dump the return low & pull air from the upper hallway (then all you need is a small chase in a closet or...
Unlike some that advise pulling from kitchens & baths - I would generally stay away from that as that is one reason why peoples HRV's freeze up & ERV's will just reintroduce the stuff in the air (use dedicated exhaust vents in those areas - no worries as it should pull in make up air through the ERV/HRV intake even with it off)
I would also recommend that you stay away from ones connected directly to a forced air system as you never know how they will use it. This also will not allow for fresh air to be pulled in as makeup air as those require mechanical dampers.
Be careful as some states require all the ventilation aspects be handled by a licensed HVAC company
Thanks Sean, great information and a lot to think about.
Depends on the home and what problems you are trying to solve.
Existing homes you can identify specific problems that have occurred over time and work on remediation.
New construction, you need to work toward the standard and apply your experience.
Attic runs (all those outside conditioned space. Don't worry about the exhaust air. After it is processed by the unit, it doesn't matter. Intake may merit some consideration. Always watch the placement of fresh air intakes.
The panasonic is designed to be a drop in (think head of a mini-split). The fan tech unit is designed to be hidden away. I mounted my Fan Tech in the garage. The supply runs through 20 feet of attic.
In all the REM files I have worked with this, the cost is the current pulled by the fan minus any heat/energy gained. Worst case you lose your gain and end up with the cost of juice to run the fan. I've seen those numbers run from 75 - 150 per year. Best case is 50% of that back for gains. Still a cost.
This is not an efficiency issue. It is a comfort and safety issue. When you create comfort people stop doing energy inefficient things to obtain comfort. Think turning on the AC in a Heating climate in February.
Buy the iPad app from Rick Karg, get the free spreadsheet from Paul Raymer. Both sit on the committee that wrote 62.2. The calculations are not that hard and when you comp out the spot ventilation and infiltratrion numbers, you will be nicely surprised at the smaller amounts needed. I just finished the calculations on an 8500 sf home. The plan is SPF for insulation. The last BD I did for the contractor came in at 1 ACH at 50. Using that, this home needs 74 CFM 24/7 of balanced ventilation.