Zehnder price shock: best bang for buck alternative?
Looking at a Q600 quote for our build. 2150 conditioned feet on main level and another 2150 conditioned feet in the basement.
Quote came to $16,783 and does not include commissioning.
So we’d have to install it and attempt to balance the system ourselves.
The only alternative I’ve heard much about is the Broan 160 and 210. They are cheaper but it looks to me like I’d need two of them to match the Q600 especially since they only make about 2/3 of the capacity they claim. I’ve also read of people complaining that they are noisy depending on how the ductwork is managed.
Broan would also require an HVAC guy to do the ductwork to match the Zehnder setup whereas I could probably do the Zehnder install myself. I’m assuming an HVAC guy doing ductwork that would match the Zehnder system would be fairly expensive so maybe the end result costs are comparable?
I should mention there is no one within several hundred miles of me that is doing this kind of a build so HVAC guys that would do the work will think I’m smoking crack if I try to have them make ductwork that would match the Zehnder unit.
I was mentally prepared to spend $13K on the Zehnder. So $17K isn’t totally out of the realm of possibility but it’s just another thing…
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The Zehnder unit itself is not that expensive, all the bits is what adds up.
One option you can look at is going with hybrid ducted setup where the fresh air is send to the return of the air handler and the stale air pickups are in the bathroom (doesn't hurt to also add one in the main bedroom).
The Q series are auto-balance so they work well in this configuration.
This would cut a fair bit of the cost out and be a much simpler install.
How much cfm are you aiming for? Are you installing an HVAC system with an air handler that can run continuously? My air handler uses 500 watts so I only run it when my single stage heat pump tells it to, otherwise I might have ducted an ERV to the HVAC ductwork. Instead I installed a Broan 210 ERV with independent ductwork. The 210 itself "only" costs $1600 so if you really needed to install 2 they wouldn't cost that much compared to everything else. I usually have it run at 65 cfm continuously which is relatively silent and uses 23 watts and have a humidity sensor in a bathroom to boost it to 170 cfm which is more audible but fine.
Shooting for 150 to 170 continuous and closer to 300 in boost mode when someone is taking a shower or whatever.
I hesitate to suggest this because I've not tried it and it goes against recieved wisdom. Running separate exhaust fans in kitchen and baths (on timers!) will allow you to size the zehnder unit to constant flow rather than boost flows. This might allow you to shave some cost by downsizing to a q450 and maybe eliminating some ducts and registers. The zehnder auto balance feature will probably handle some but not all of the flow of a bath fan, so while the fan runs, the building will most likely be under some negative pressure;. Range hood flows are higher so you would need a mechanical damper for makeup air.
I might be causing trouble here — Zehnder definitely advises against this strategy. But dedicated exhaust does potentially clear more moisture from bathrooms and cooking vapors more quickly. The risk as I understand it is that a depressurized building could draw in moisture or radon or soil gas or what have you—partially negating the value of the zehnder. But if it’s an occasional temporary condition those concerns might be tolerable?
If the basement is an open floor plan you could look at a more conventional unit (Broan, lifebreath etc) down there with simplified ducting and probably go to a q350 upstairs.
Indoor air quality has real health benefits and we spend a lot of time indoors. I’d save money some other place—countertops, cabinets, tile, the trendy the stuff that might get redone in 20 years.
The RenewAire EV Premium series might be something to consider; the "L" model can do 30-280 CFM while the new "X" model can do 100-390 CFM. Their tech support folks were very helpful when I was trying to track down an issue with the optional boost controls (in a nutshell, DON'T use the "PBT" push button timer control, use a "PTL" percentage timer control located by the ERV and use "PBL" push button boost controls where needed; the PBT is sensitive to electrical noise that can trigger boost mode).
I'm getting a RenewAire for my house. My HVAC guy is only tacking on about $5k to add it while he is doing the install of the central heat and air and according to HVI, it is actually a couple points higher than the Q600 in efficiency (88% vs 86%)