Suggest you supplement with an inexpensive wine fridge for the really good, longer lived, stuff (assuming it’s not all really good stuff).
Attic is pretty well ventilated. Ridge and soffit vents. We had baffles installed an an extra foot of blown in insulation done last year and we already made back about 25% on heating and cooling bills last year. Also replaced a door that was basically R0.
We have a FLIR camera at work and I did a lot of sleuthing around the house. Those things are great for finding leaks or places with no insulation. Sadly when I used it on the potential wine cellar area, it told me what I already knew – my basement is a pretty even temperature (about 66F right now) with no obvious cold spot. Floor was colder and walls were an even gradient from the floor all the way to the normal house temperature on the ceiling.
Apologies if I missed it but do you have heat venting into the basement or some other heat source? if not, then this seems high for this time of year. You should be close to the coldest time of the year and much colder than that if there is no heat source. If there is a heat source, then I ignore my worry. I had something similar and it wasn’t until I put up the walls that I got a real read on what the temp would be in the cellar.
The furnace and water heater are about 15’ away from the potential cellar location. Ducts on the ceiling of the basement, which are not insulated at all (yet). So yes, there is an active heat source and I’m sure I’m getting flow down from the 1st floor of the house. But the floor at the edge is about 58 degrees. There are no vents or returns in the basement, though.
I’ve put pieces of Rmax (R13) insulation on the floor and the temp drops considerably underneath with just this small amount of insulation. So there’s obviously a lot of heat flow down from the ceiling and I can’t discount lateral flow through the slab from the HVAC. I plan on building a wall isolating the mechanicals and my wood shop from the cellar/rec area and will insulate that.
So I’m in the same boat, I’ll probably just have to build the walls and see what happens. I can always buy an AC or CellarPro unit later.
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Actually a temperature of max. 69°F (which is 20-21°C) isn´t that bad at all. Many wine cellars of producers in Southern France are that high in summer. Over the years the wines might age a bit faster than at 55°F throughout, but that´s not necessarily a bad thing.
So if you don´t want to install active cooling you can well live with it.
Never forget that Insulation is a two-edged sword.
The overwhelming majority of insulation systems in North America are designed to keep COLD OUT and HEAT IN.
But you’re trying to create a refrigeration system in your basement, and that means keeping COLD IN and HEAT OUT.
In fact, to a certain extent, when you re-engineer your house to keep your wine cold, the idea of saving money on your heating bill should be a little worrisome.
What I’m hearing hear is:
A) Insulation beneath the floor slab in the basement [keeps COLD OUT & HEAT IN],
B) Insulation somewhere in or on the sub-grade walls of the basement [keeps COLD OUT & HEAT IN],
C) A lot more insulation between the lower level living quarters of the house and the house’s attic [keeps HEAT IN, because heat wants to rise].
It sounds like you could be so well insulated that you may have to introduce some artificial cooling, simply because the cold has no way to enter the basement, and the heat has no way to rise up and exit the basement.
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I completely agree that there’s nothing wrong with storing your wine in the 60s [Fahrenheit].
The 1811 “Year of the Comet” d’Yquem would had to have been stored in the 60s for about a century, until Willis Carrier finally invented air-conditioning in 1902, and people seemed to love that wine well into the 1990s [unless maybe they were drinking fakes].
And I doubt that very many wine cellars anywhere in the entire world were artificially cooled much before about 1970.
However, I also agree that the temperature seems wrong for this time of the year. If there really is some 57F soil down there somewhere, then the temperature on the basement floor ought to be a lot closer to 57F than to 66F.
The soil temperature could certainly be out-of-phase with the atmosphere right now [the soil always tends to be out-of-phase with the atmosphere], but I’m worried that there’s so much insulation that the heat can’t get out, and the cold can’t get in.
And in the summertime, when you want the deep earth temperature to be badly out-of-phase with the atmosphere, all that insulation will be keeping the cold out, and the heat in.
I think I’m just losing that much heat from the ceiling and ductwork (both uninsulated). The wall / floor temp at my north side is 57 near the floor. The floor averages about 66 across the whole slab. But definitely cooler around the perimeter. The true test will be when I insulate the ceiling and wall off the duct/furnace area. Once robbed of this heat source the slab should cool off considerably. If it doesn’t then I’ll know I have a lot of extra insulation underneath. The ASHRAE calulator estimated 500BTU/hr for just duct loss. I’m sure heat gain through the ceiling is pretty high as well as the house is mostly hardwood over plywood.
I have a soil thermometer outside about 2’ down and it’s showing 49F, which fits Gold’s model for my area and a 9F house-warming correction, also from Gold and confirmed with a few websites (that deal with geothermal, solar heating, and root cellars). So outside the house seems to fit the model pretty well.
One of my disappointments with the book are dealing with the floor. He says the concrete is R2 or so, then talks about insulating effects of the soil and it’s closer to R40, but then does an experiment with plastic sheet (R1) and the temp changed noticeably. His conclusion is that R40 was too high an assumption for the floor, but then never revisits what a better value would be. Since the floor is the main heat sink in any cellar, you figure that would be the most important R value to know!
Thanks again all for the input. Nice to be able to bounce ideas and concerns off a sympathetic and educated group.
I’m in MD (Gaithersburg) and I have a passive cellar. It’s all below grade, no windows. I closed off all vents in that room and around it. The temp hovers between 60-65, not much variation and the humidity is fairly constant at 45%. It’s actually in the south west corner of the house but furthest from the HVAC. We have enormous oak trees around our house so not a lot of direct sun.
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What kind of wines do you buy and how long do you keep wines?
What do you do with your AC when you go on vacation in July/August and how does that impact the temperature of the wine?
Is 45% humidity considered low for wine storage at 60-65?
Yes, I think it is
The answer here is subjective. If you are fine with say 5-10 degree swings up to the mid 60s then yeah it is gonna be fine. If not you’ll need to go active. You will get a different opinion on what swings or temps are fine from just about every person. Much depends on the wines you have and your goals for any long term storage.
Two pieces of advice
- plan to add active cooling so if you decide to the vast majority of the work is done
- if you plan to have high high value bottles that may ever go to auction “wine pulled from passive cellar in VA” is gonna definitely hurt the resale. May not matter.to you.
Right now I’m scaling up to wines that need to age. I have a decent assortment of Pine Ridge and Ridge wines that could use 5 to 20 years. But the vast majority are 5 to 7 year agers (GSM, Zins, various Pinots). I developed a taste for old Bordeaux (mostly 2CC and 3CC) I have avoided too many super-valuable wines because I knew they’d be at 70F for a while. But once the cellar is built . . . 
I’m reworking my model for my floor R values. I took some measurements along the slab and the gradient is more than I thought. I can’t discount the heat flow from the slab towards the cooler cellar area. At worst, that heat flow is almost the same magnitude as what flows straight through the floor with the cellar temps I’m looking at. Reality is probably about 1/3 that based on soil temp distribution. When I worked that into the model, I’m getting R values of about 4 for the floor (reasonable for a slab over gravel). Also means I need to insulate from the mechanicals and ducts and insulate the ceiling around the cellar area to keep as much heat on the 1st floor as possible.
Sounds similar to my experience. I’ve installed cabinets along one of exterior walls of the wine room. I’ve put in R-21 batts under the cabinets in the hope that there will be an 18"-24" buffer on that wall where the exterior floor/slab may be a bit cooler.
I also wrapped the exposed hot water lines in the open area of the basement, and I’m going to install covers so I can block the windows in the summer. The rest of the basement was running 75F-77F in July and August. If I can get that down a bit, it would help. Walling in the boiler and water heater area would help, as you discussed, but for various reasons, I’d rather not do that.
Remember that every single wine cellar in the world was passive until mid-way through the 20th century, and many still are. Ever read breathless reviews of the 29 and 47 bordeaux? Every one of those bottles was stored in a passive cellar for decades before moving (presumably) to an active cellar, and every single bottle tasted here was shipped to the states in an unrefrigerated container ship. I don’t know the status now, but I seem to recall that as recently as the last 15 years or so Margaux’s cellars were still passive (and get up to the mid-60s).
I think people make way too much over cellar conditions. I think this is one of the unfortunate legacies of the Parker era (all of his “stored at 55” posts). The hard data on the impact of slightly warmer/less stable cellars is thin to non-existent; what we have are anecdotal conclusions offered that an active cellar is required, universally from people who have them.
For my personal (and no doubt idiosyncratic) perspective, you might be over-thinking this a tad.
Oh, I am positive I’m overthinking this!
Thanks for the insight. I think I am going to try passive, see what I get and just be prepared to cool it if necessary.
I drink often wines from the cellars of two friends with passive cellars in the DC area. One drinks his wines on the younger side and the wines usually show well. The other ages wines much longer and his aged wines tend not to taste as good as the same wine tasted from cellars using cooling units. A bit duller.
This is basically my set up in suburban MD.
I have a ~150 or so bottle fridge (Costco Wine Enthusiast series) in my unfinished storage space and then an under the stairs passive set up for the remaining 600-700 or so bottles. The passive set up is in the finished portion of the basement but with no vents - drywall over R10 foam over 10" foundation walls. I have a thermometer monitoring the space and it never gets above 70-71 in the summer and in the winter its generally 62-64.
Tbh, I have a curiously higher rate of spoilage (anecdotal) in my main level “convenience” under counter unit than the passive space downstairs…
Lived in Warrenton, VA (northern Virginia, foothills of the Blue Ridge) for 20 years. Basement, 7 feet below ground level, stayed at 50 - 70 year round at floor level. OK by me.
Had a closet under the stairs. Stayed at 55 - 65 until Spring, when I opened the door and let the air conditioner keep it below 70. Worked fine until I moved to Maine, which has been much easier.
Dan Kravitz