Hi there,
My basement just flooded, necessitating some work, which means it’s time to redo the cellar. Having relied on a mostly passive system, I’m looking at installing a unit from CellarPro, but I’m unsure of how to think about a split system versus single self contained unit.
The split systems cost more, have worse warranty and cost more to install and service (according to CellarPro). Still I have this urge to do split. Can somebody help guide my thinking on this?
You may get a real expert to chime but having put a few sytems in my cellars I know a but. Have had all in one, split, ducted, and now a mini split. The ducted system was the best but certainly the most expensive. I would not do all in one for a variety of reliability, access, repair and venting reasons. The current mini split is the best of both worlds being super quiet (unlike other styles split systems) and uses commercial, name brand gear (Mitsubishi). Any good HVAC guy/firm can and will service it immediately. This is really key I personally will not buy “wine” refrigeration systems but always opt for a commercial refrigeration specialist to do the install. That way they put stuff in than can be serviced and size it correctly. I expect I pay a bit more but not that much. I can not stress that enough as eventually you will need service and this is where things often fall apart. Good luck.
John,
This is good advice. So you ended up with a Mitsubishi?
Yes that is who makes the mini-split. I contacted a local firm that does commercial refrigeration. They also do regular resi and commercial HVAC. Did a great job all around.
Most traditional split systems are like a walk in coolers and the evaporator fans are pretty noisy. In this, super quiet. The Temp sensor needs to be “tricked” to go down to 55 degree. The device is called a Cool Bot.
Correct me if I’m wrong, but I didn’t think “off the shelf” mini split brands like Mitsubishi allowed you to maintain proper humidity? That’s the reason for using a product designed specifically for wine cellars.
HVAC units (wine or otherwise) do not “maintain” humidity. A refrigeration system can be somewhat designed with high humidity in mind (i.e. think meat locker). But in any real amount to add humidity one needs a separate humidifier. Removal (if more than HVAC unit does regularly) is done with a thru de-humidifier. I’ve used both when I live in CO and NC respectively.
Really all those ads that note “cellar” and wine refrigeration systems that manage humidity are bunk. But they sure sound good. Really they simply monitor it but anyone is free to believe what they wish 
John - That’s my point, my wine cellar designed mini-split equipment keeps the room at a constant 60% humidity level and the rest of the house cooled by ducted systems is 30-50% range. Are you saying using a standard mini-split will achieve the same results in the cellar?? Doesn’t sound right.
Hey John,
Mine keeps near 60% humidity but only because that that is where it settles in, not thru an active control framework. In summer here in NC I have seen 70-80%. Unless you are really actively humidity controlled I’m not sure how it is fixed at a constant 60% year round. Maybe you have active control somewhere which is usually a separate method, usually by reduction inherent in evaporators. Regardless I’d be happy there!
Most people don’t even watch it in their cellar. But after needing to add water in CO, I am always sensitive. Most non-desert locations it stays fine without any adjustment.
I’ve so many (usually cheap) wine fridges and coolers say temp/humidity control that really are nothing on the humidity side other than what any A/C does and maybe a monitor for the humidity level. You may have something different.
Wow. I have to admit, I am one of those people who thought that when CellarPro said they “maintain optimal cellar temperature and humidity conditions,” that actually meant they managed the humidity. I live in DC and humidity/mold/black mold is definitely an issue. Sounds like I need a separate unit.
I think before you get too worried I’d ask them exactly what they mean by humidity control. I could be wrong. And regardless just look and see what it is when up and running for a while. If you determine you need a de-humidifier a good one is about $200 plus or minus on Amazon. I know my new cellar started off too dry (new racking) then got a bit humid after I added moisture. Now it stays fine all by itself here in NC.
I think John S is right. The principle behind any cooling system is pretty standard - you let a gas expand and contract and in so doing it takes heat energy from one place and puts it in another. Then you blow air over the lines that get cold and that goes into the room or the box or whatever. Cold air holds less moisture than warm, so you drop the humidity. But unless there’s a separate unit that monitors humidity and that is connected to a water supply, you don’t get humidity control with a cooling system, including those “designed” for wine. Depending on where you are, if you seal the space relatively well, you can maintain a constant humidity level and my guess is that on the east coast it’s closer to what you might want. That said, I’m not entirely convinced that the necessary humidity levels are as high as people believe. I’ve been in San Diego for a few years now which is as dry as it gets. Although I haven’t worried about humidity in the least, the desert air hasn’t sucked all the moisture out of my corks.
Fwiw, our CellarPro units (like all HVAC and refrigeration equipment) are designed to balance the coil dimensions, temperature and airflow to achieve specific temperature and humidity conditions. Assuming a normal cellar temperature range of 55-60F, the resulting RH (relative humidity) will balance out around 60% for CellarPro cooling units.
Factors that will affect the balance point include the runtime of the cooling unit (less runtime = more RH), the airflow (more airflow = higher RH) and the ambient environment (dry climate = less RH). For the last variable, we publish a chart that provides guidance based on your specific ambient conditions: Ambient Humidity Chart | CellarPro
Speaking from direct experience (we’ve tried to build cooling units for other applications with different temp & RH balance points), when you want to change the design parameters of refrigeration or HVAC equipment, it’s much more complicated than just changing the thermostat setting. For example, each system uses a compressor that has been built with specific design parameters, and balanced with expansion valves, charge, airflow and coils sizes, to maintain temperatures and RH within certain ranges. When you go outside of the design parameters for the equipment, there may be unintended consequences and the equipment’s warranty may be nullified.
Whereas wine cooling units are designed to maintain ideal conditions for wine storage, HVAC equipment is designed for people-comfort, which is much dryer (around 20% RH) than wine storage. For this reason, we don’t recommend using HVAC equipment for wine storage (no disrespect intended for the “Mighty Kenmore”).
CellarPro cooling units will try to pull out excess moisture by condensing the excess on the evaporator coils, which then will drip into a drain pan and out through a drain line. Assuming the cellar isn’t located in an overly humid geography, the key to the cooling unit’s ability to pull out the excess condensate is that the cellar must be airtight when the doors are closed - ie the infiltration of ambient air must be limited. Our “adjustable humidity control” features include variable-speed fans, which can be toggled to increase or decrease the RH inside the cellar, and fan cycling control (of the evaporator fan after the compressor turns off), which also can be toggled in 1-minute increments to increase or decrease the RH inside the cellar. Note that our units don’t PRODUCE humidity (unless the unit includes our humidifier), they simply allow you to manage the amount of condensation and recycle moisture back into the cellar.
When we see custom wine cellars with cooling units that produce a constant flow of condensate, invariably we find that the cellar is not airtight - eg it was built without a vapor barrier, has unsealed concrete walls, etc.
Despite first saying that all HVAC equipment is designed to balance RH at 60%, and then saying that residential HVAC targets 20%, I think Ben may have a point. Does anybody who uses the mighty kenmore, or a mini mighty split, have a comment on this?
Hey Thomas,
I honestly don’t think this needs to be that complicated. If you like cellarpro and are confident in 24hr service if it breaks go for it.
FWIW, my current cellar is at 70% humidity which I love. That is just at equilibrium. It is lower in the winter of course near 50-60%. I’ve had a few designs and 20 yrs of various setups in various cellars as I’ve moved. None ever broke (commercial refrigeration types installed/designed), all maintained humidity as I wanted via adding or subtracted H2O as needed and this was in CO where I needed to add water. With all that said, as long as it is not too high (mold) or low it is fine. I think most on the East coast are fine albeit some find they need a de-humidifier in the middle of summer.
Oh as noted above the proper design (insulation and vapor barrier) are really keys to a well running cellar. Good luck with the project.
No offense to CellarPro, but how would I be confident in a service I never used? I’m sure we all struggle with the exact same issues. I’m just trying to learn from those who have already walked down this path.
My reasoning why a split system is best.
Why I would not do a minisplit, by the time you buy, install, trick out, you’ll end up with a system working outside it’s design parameters, few technicians can diagnose these well and the parts are NEVER in stock.
Chris,
Thank you for chiming in. You clearly know what you are talking about. What would you do then? I surmise from your post you prefer splits, but since you mention service, I am also guessing you are not backing the wine specific systems (as there just are fewer local technicians for these). Please share!
The problem with the wine specific systems is the use of proprietary parts. The result is extended down time and higher repair costs.
My preference is towards built up split systems using off the shelf components. These systems have components that all technicians understand and have easy/local access to parts. The caveat with this however is to find someone who can offer properly matched components and a nice install.
Sorry about that - my grammar left something to be desired - I cleaned it up, so hopefully it’s clearer now. What I was trying to say (clumsily) is that all systems are optimized to achieve certain results. Eg HVAC equipment is optimized to produce 72F and 20%RH; CellarPro cooling units are optimized to produce 55F and 60% RH; etc.