Humidity problems for large tank

[ClubReef]

Wow..thanks for sharing your experience. I'm glad you've got everything under control

We installed central AC this summer and I've noticed less humidity on my 90G which is located on the main floor. Do you think that a large tank placed in the basement combined with AC will be good enough to keep the humidity in check?

I have thought about the basic bathroom fan ventilation system but I'm not crazy about the whole buzzing sound..and I've read on RC that this approach is not recommended because you draw air out and not replacing it.

So if I decide to go with an HRV unit..how much can I expect to pay??

Thanks

Originally Posted by Delphinus

You bet. You can count on bigtime humidity problems such as weeping windows in the winter, mildew forming on the walls and ceilings, particularly north outside walls of your house.

I ran a dehumidifier for many years, but the effect was localized and it's noisy as all get out. If you have a family, expect them to hate it.

I dealt with this problem with the equivalent of a BFG a few years ago. I installed central air and an HRV. You don't have to do the A/C, that's only for comfort and cooling in the summer, but the HRV is, in my opinion, what saved my house. I don't even have my 280 running yet - I just had evaporation from 3 reef tanks (110g, 75g and 40g - plus a FW tank I suppose too was helping add to the humidity) and it was causing HUGE problems. For me it came down to - consider the HRV, or consider quitting. Mildew on the walls, especially if you have a family - it's a no-brainer, you can't live with that.

If you're handy you can install one yourself. I believe BMWRider on this board did an install himself. I had a place that was recommended to me by Monza do mine - they did a whole analysis based on square footage, amount of air turnover required for the projected humidity, and came up with a unit sizing recommendation. I then asked them for the next model up just to increase my margin of error. Yeah, this was expensive (basically the cost of a nice large tank with all the trimmin's .. but .. like I said, it was this, or quit. And I figured since I was going for broke and they were going to tear my furnace ducting apart anyhow, might as well throw an AC on there. I have a south facing house and man did the house get hot in the summer. No more. Also no more heating problems among any of the 4 tanks. Sweet. No regrets.)

An HRV has other benefits. Now that I know what they are, I'd never consider living in a house without one.

What some people do is just vent the tank room with a bathroom fan or a furnace booster fan. This is OK in some circumstances, but it has a few drawbacks. One, you only vent air out. You rely on the furnace, and overall house leakage, and so on, to replace the air that is drawn out. Plus they are noisy (at least some are - my bathroom fans are horrendous, I'd hate to have to listen to that all day long).

An HRV (heat recovery ventilator) is basically a fan that draws air out - like a bathroom fan - but - it replaces the air it pulls out, running both streams through a heat exchanger. You recover something like 85%-90% of the heat of the outgoing air. This is important in our climate ... you'll be happy you're not pulling in air at -20 in those February coldsnaps.

It works to turnover the air volume in whole house so your air quality improves without costing you having your furnace run full time to heat the incoming air.

Anyhow like I said it is a very heavy-handed approach to eliminating humidity, but after a few years of weeping windows and mildew formation, I was ready for heavy-handed. Other people do make do with the bathroom fan vent solution, or the booster fan, but ... to me ... I think the real "once and for all" solution is the HRV.

[Delphinus]

Originally Posted by ClubReef

We installed central AC this summer and I've noticed less humidity on my 90G which is located on the main floor. Do you think that a large tank placed in the basement combined with AC will be good enough to keep the humidity in check?

In the summer, yes absolutely. But in the winter, not really, because you probably won't be running it in the winter. It's actually the winter where it's more of a problem because of the walls and windows being cooler, the water condenses onto them because of the cooler surface.

So if I decide to go with an HRV unit..how much can I expect to pay??

Roughly the same as central air. Maybe a little less. If you're handy you can do it yourself (Home Depot sells HRV's - I didn't know this until after I had mine installed). It's just basically a box with 4 holes in it. Two go to the outside (so you have cut vent holes, like for a dryer), one is the ingoing and one is the outgoing - and the other two go inside (again, one is the ingoing and one is the outgoing). You can either bring these to your tank room, or just some central spot in your basement (well.. not next to each other obviously, otherwise you just vent that one spot ), or, you can have the venting go to your tankroom AND cut into your main furnace lines so that the whole house can get some recirculation happening. I think if you do this you may need to get some interlock happening so that the furnace fan turns on when the HRV is doing its thing. If you just vent the room then you wouldn't need this. But I figure if you're going in for a penny you might as well go in for a pound. I wouldn't know how to do the interlock myself but on the other hand it's probably not that bad to figure out.

I used these guys: http://airproheatingairconditio.supersites.ca/door/
They came recommended to me by another Canreefer (Monza), I think they've done a few other installations for Canreefers. At any rate, they know ALL about aquariums and humidity, they seem to have done a few jobs for guys with big tanks. I was very happy with them in the end. Might not have been the cheapest but they did, what I felt, was a proper analysis of the situation. (I had two other places do estimates.. one guy just told me a number over the phone, another guy came to my house, looked in the front door, and THEN came up with a number. I really needed something more than a WAG because I had a specific problem that needed to be fixed - I was not about to plunk down $1500 or whatever and then discover that I still had that problem. But what AirPro did was produce a whole document that explained how the product was going to solve the problem, what sizing of unit was needed, and so on - so I had a degree of confidence that this wasn't just a silly thing to do, it was going to fix the problem, and if not, I had some recourse available to me.)

[ClubReef]

Thanks Tony.

Does your HRV run 24/7 or is it on some type of humidity control?

[Doug]

It usually runs 24/7 in the winter, spring & fall. Summer operation would be optional, as the outside air is very humid and the CA, dries the inside air.

It runs on a low speed and can be bumped to high by a humidity control sensor or timed switches placed in bathrooms.

[Reefer Rob]

Our climate on the west coast is a lot warmer (and wetter) in the winter, so this may not work for you. I just have an in line fan that exhausts air from my canopy to the outside. I wired in a 3 speed switch in line, and low speed works great in winter. Even with the fan on the aquarium still provides most of the heat for my house, my furnace rarely comes on except during cold snaps (we keep our house at 18 C).

[Delphinus]

Mine is on a dehumidistat which is set on the wall on what will be my tank room (currently just a random wall in the basement). It also has an manual switch upstairs to run it on a timer (eg. 20 minutes or 40 minutes - kind of nice if you, say for example, cook something stinky like bacon - takes care of that lickedy-split). It's never technically on "24/7" - on continuous mode it's on for 20 and off for 40, and shuts off if the humidity is lower than the dehumidistat setting.

I shut it off in the summer, set the humidity setting to zero and turn the fan off and just let the A/C take care of business.

Originally Posted by ClubReef

Thanks Tony.

Does your HRV run 24/7 or is it on some type of humidity control?

[fkshiu]

I had an ultra-quiet Panasonic bathroom fan installed above my 150g system in my basement. Simple and works great on a programmable timer.

I don't know about the "drawing air out and not replacing it" theory - if that were true houses would be imploding on a regular basis from the vacuum created everytime someone took a huge dump after some Mexican food. The fact is that the air drawn out by a bathroom fan is being replaced by air from elsewhere in the house. No house is 100% airtight. If you want to be sure just pop open a window for a bit to make sure fresh air is coming in.

[Delphinus]

No, but you don't want to leak -20 or colder air into your house. You don't have to worry about that so much in Vancouver, but the rest of the country might.

[Reefer Rob]

Originally Posted by Delphinus

No, but you don't want to leak -20 or colder air into your house. You don't have to worry about that so much in Vancouver, but the rest of the country might.

It only takes a small amount of negative pressure in your tank room or canopy to keep the moisture out of the rest of the house, a very small fan will do.

We installed an HRV system in a house we built in Campbell River, and it was great to have the air always fresh in the house, but I wouldn't do in just for an aquarium. I'm not sure you will ever recover the cost of an HRV in energy savings. This hobby already sucks back way too much cash!

[Snappy]

Darryl,
I only have a med size tank, 130 gal, but have over 200 gal of water going and I don't have the same humidity problems people are talking about. Maybe it's because my house isn't new?