Acceptable Humidity Levels

[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.

Originally Posted by 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.

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.

Originally Posted by phillybean

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

http://cgi.ebay.ca/Soleus-CFM40-Port...QQcmdZViewItem

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.

[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.