Acceptable Humidity Levels

[Parker]

What would be an accept table humidity level in the house? I have a total of 460 gallons in the basement with a humidity level hovering around 75 – 80 %. With the recent addition of a 265 my wife noticed the increase humidity in the behavior of her hair ( I laughed at first ) The 265 is no where near ready to run, I have it full for a leak check. The plan was to add an exhaust fan to vent to the outside above the tank. How much could I expect the fan to lower the humidity?

[Jason McK]

I believe between 50-60% is normal

J

[Delphinus]

The fan should help, but then you're relying on the doorjambs and windows and furnace intake to replace the air that is drawn out.

75%-80% humidity is going to end up being a real problem for you. When it starts to get cold outside you'll see what I mean - the outside walls and windows will get a heavy condensation form, especially at night, and this in turn causes things like mildew and mold. In the summer it's not so bad, in fact you may even get to like the humidity - but yeah ultimately 75% is way too much for our climate.

I know this because humidity has been a problem I've been battling for years with my tanks. In my old house, the outside walls were 2x4 and this wasn't adequate insulation against the temperature differentials. So I built a new house using post-2000 building code rules and guess what, now houses are so air-tight in their quest to be more energy-efficient, that it's the same problem all over again (just due to a different reason) - the house just doesn't have enough air turnover to shed the excessive humidity.

Anyhow, the fan should work. It's not the best solution for our climate but it will vent the wet air out, which is what you want.

The ultimate solution is to use a HRV ("Heat Recovery Ventilator") instead of an exhaust fan. The concept is basically the same (ie. venting air to the outside) but with two important details: 1) The air that is vented outside is replaced by air from the outside, thus removing the "air deficit" that a fan alone would create, and 2) It uses an heat exchanger to use the outgoing air to preheat the incoming air (which is important when it's -40 outside). They recover something like 85% of the heat of the outgoing air, which is good when it comes time to look at your monthly heating bills. :)

Anyhow hope this info helps. Definitely do a fan or something, 460 gallons evaporating into your house will have an adverse effect.

[littlesilvermax]

I have 350+ gallons in my house and never get above 55% or so. I am usually at around 40%.

You need an HRV or else be prepared to get mold. Then you may as well just burn the house down.:neutral:

[phillybean]

What about dehumidifiers? I think I spelled that wrong but you know what I mean.

http://cgi.ebay.ca/Soleus-CFM40-Portable-Dehumidifier-Dehumidify-Air-NEW_W0QQitemZ190143862356QQihZ009QQcategoryZ79621Q QssPageNameZWDVWQQrdZ1QQcmdZViewItem

[Joe Reefer]

HRV's are only an option to reducing heating costs by recovering some of the heat being exhausted. To elimate moisture issues you must "exchange air" simple as that.

If you are truly serious about not having any moisture issues, a make-up air system should be considered. This would include a small furnace with a stainless steel heat exchanger to draw 100% fresh air from the outside, there would also be an exhaust fan interlocked with the furnace. The cfm output of the furnace and exhaust fan should be close in performance. An HRV can then be used on this to recover some of the cost running this system when its -40.

[ponokareefer]

For whatever reason, our house is at 75 humidity as well and we are having problems as listed above. As we only have a 3 gallon tank in our house, the issue has to be other things. We are looking into getting a dehumidifier to help with the issues. From our research so far, Home Depot seems to have some at reasonable prices with quality names.

[aussiefishy]

I think i will share my experiences.

Last winter was the first winter for my 350 gallons in my Townhouse. The humidity is really a problem, Condensation at the windows (turns to Ice at the window sills), Fallin ceiling paint and damp clothes.... that was what happened when you have -20C outside and a humidex of 60.

I bought a De-humidifier and that helps out alot. but the bad thing is the electricity bill, without the dehumidifier the bill already reach$2XX... with it on the billi was about $45-50 dollars more/month.

i think about the exhaust fan idea, but i ask a couple friends that are in the HVAC trades about it and they all think it is dangerous, because if you have a low power fan, it will not do much. if you use a high-powered exhaust fan blowing humid air out, some air has to come back inside your house, it can either come from your freshair intake OR your furnace exhaust -- very dangerous CO poisoning, and your gas bill WILL go WAY UP due to cold air coming in.

so i was recommended by others to try a HRV - heat recovery ventilator.

this unit i bought don't cost much to setup and it will do a few things for me.

1. bring a constant supply of fresh air from outside while heat is retained.
2. build in HEPA filter helps me breath a little easier especially if you have other pets.
3. remove excess humidity.

these in turn will lower my energy bills, my doctors bill and keep your family member happier - another example would be like choosing between a air conditioner(your family memebr enjoys it TOO) or a aquarium chiller(only your fish can enjoy).

This will be my first winter with a HRV so i am not sure will it perform the way i want it to, but it certainly solve most problems encounter by me.

just a 2 cents.

[TRS]

I would like to hear how you make out with the HRV this winter. Last fall I installed a Humidex unit (http://humidex.ca/index.htm) to replace my dehumidfier as well as its operating cost. It is quite cheap and easy to install. Have any others tried it? The Humidex unit is a very simple concept, drawing cool and moist air from the floor and venting it to the outdoors. It is very quiet and kept my humidity level between 40 - 60 percent all winter and throughout the dog days of summer. It is fine, but as I continue to add tanks to my fleet...the humidity will become more intense. The next step may be an HRV.

[fortheloveofcrabs]

I don't mean to pry, but how much do these "HRV"'s cost? And where can you buy them?

[Parker]

Thanks for the advice all. I have some time to sort this out, once the tank is drained from it's leak test it probably won't be filled again for close to a year.

However we are renovating our home at the moment and part of that renovation includes HVAC upgrades so tacking on a HRV at the same time would be a minimal cost.

Aussiefishy, do you have a brand name of the unit you chose?

[Delphinus]

I've written about HRV's now several times on the board, I'll try to find the posts where I've done so, so that I can point to those as well.

Basically - the HRV will solve your humidity problems (assuming your outside air is less humid).

An exhaust fan will draw the air out - but if you don't replace the air going out, you have an air deficit. This can be a problem. First of all, it means your going to be heating your house more than you should. Secondly, if the house is too air tight then that air is going to come in through whatever means it can - and as Aussifishy pointed out - this can be a serious threat if if comes in through a furnace exhaust vent.

Stove top fans, for example, over a certain amount of cfm, building code requires that there be interlock with the furnace. Ie. if the fan is on, so too is the furnace.

I had BIG BIG humidity problems in my house. The HRV solved them. It runs on a dehumidistat (opposite of humidistat) so that if the humidity of the house EXCEEDS a threshold, the unit turns on. This keeps your household humidity in control.


HRV's are only an option to reducing heating costs by recovering some of the heat being exhausted. To elimate moisture issues you must "exchange air" simple as that.

If you are truly serious about not having any moisture issues, a make-up air system should be considered. This would include a small furnace with a stainless steel heat exchanger to draw 100% fresh air from the outside, there would also be an exhaust fan interlocked with the furnace. The cfm output of the furnace and exhaust fan should be close in performance. An HRV can then be used on this to recover some of the cost running this system when its -40.

Not quite correct, Lando. The HRV is a heat exchanger AND an air exchanger. It pulls air out of the house, and draws air INTO the house.

You shouldn't need a second furnace - the HRV, if sized correctly, can and WILL solve the humidity problems.

What about dehumidifiers? I think I spelled that wrong but you know what I mean.

http://cgi.ebay.ca/Soleus-CFM40-Portable-Dehumidifier-Dehumidify-Air-NEW_W0QQitemZ190143862356QQihZ009QQcategoryZ79621Q QssPageNameZWDVWQQrdZ1QQcmdZViewItem

They work, but they're noisy and the effect is localized. And as soon as they stop, the humidity goes right back up again. I ran one for years and it only helped reduce the problem but it did not eliminate the problem. The HRV did solve my wet windows/wet walls/mold/mildew problem.

Pricey yes, but ... it is littlesilvermax said. Once your house has black mold, you may as well burn it down. This is the reason that grow houses tend to be condemned - the humidity just ruins the house and it becomes a health hazard to those who live inside it. Our aquariums might not do the same amount of damage but, humidity is humidity. So pricey it may be, but if you have excessive humidity then it becomes the price to pay to stay within the hobby.

You can buy HRV's at Home Depot and install them yourself if you're handy with DIY. You can also call a HVAC place and have them do it.

I had a place recommended to me by another Canreefer and I would recommend the same people. They did an excellent analysis of the amount of humidity, the volume of the house, required turnovers, and came up with a unit sizing recommendation. Anyone in Calgary considering a HRV, PM me and I will give you the contact information.

[Doug]

As others said, HRV is the way to go. They run from around $800 to $1500 or so, depending on how many electronic gadgets one adds and the size of the units and an installer is required. Make sure you get the proper cfm for your situation. They even have larger two core units and ones that come with de-humidification but dont know what they would cost.

In the summer, central air usually keeps humidity levels in check.

Home Depot has some good HRV units. I like Lifebreath myself.

http://www.lifebreath.com/main.htm

[Delphinus]

My HRV is a Lifebreath as well. Very happy with it. You can barely tell when it's on, it's so quiet.

[littlesilvermax]

Once you get used to good fresh air all the time it is hard to go back.:biggrin:

[Veng68]

I'm going to change my old furnace (from the 60's) and I was wondering what extra work would need to be done to install a HRV unit?

Cheers,
Vic [veng68]

[Delphinus]

I'm not 100% sure that an HRV would give you the same bang for the buck in Vancouver or other milder and wetter climates as it would in say Alberta where it runs cold and dry for a goodly part of the year, so that's one thing you might want to check into. But, in answer to your question, if you're ripping out a furnace anyhow, adding a HRV would be only an incremental step. It's basically a box that sits somewhere near your furnace, it has 2 pair of ducts/vents (1 pair goes to the outside, the other pair goes to your furnace vents or to your room that you're targetting {or both}). So 4 vents in all.

One thing to consider if you're getting a new furnace anyhow: consider going "all the way" and get a "high efficiency" furnace (the more common ones are considered "mid efficiency").

A high efficiency furnaces uses a DC drive motor for the fan instead of AC and the cost savings is apparently enormous. For example, you can run your fan on all the time, and still pay less for heating than a mid-efficiency furnace who only turns on when needed. Having the fan on 24/7 can do a LOT to keep humidity in check because it's constantly cycling.

I wish someone had explained that to me when I put my furnace in. By the time I realized this about the furnaces (ie. the DC drives) it was too late and I had a mid-efficiency furnace put in. The cost upswing if you're buying a furnace anyhow is easier to take than the full purchased cost of a new one when your current furnace is too new to be replaced anyhow, so I'm sort of stuck. But that's why I thought I'd tell you - if you're looking at replacing a furnace regardless - then high efficiency is the way to go. :)

HTH

[Parker]

I have had two HVAC companies in an neither of them are recommending HRV's to solve the problem. Has anyone delt with a specific company in Edmonton? One company suggests venting directly over the tank to the outside and the other simply recommended a dehumidifier.

[ponokareefer]

We bought a dehumidifier and it has solved our problems with humidity in our house. We picked ours up at Home Depot.

[atcguy]

I have a 60 pint dehumidifier I bought at home depot about a year ago. 279 I believe. I havnt used it for 6 months as my levels were not high. removed the humidity in the winter for sure. !!! I am putting in a built in one through my furnace. will sell for 175 pm if interested. I think it is the Danby Brand.

[Parker]

I'm having a new furnace put in and I was trying to tie in humidity control with the furnace but no one seems to be able to come up with something..