Dehu or HRV for Garage

[buzz]

This winter I'm looking to solve some moisture issues I keep having and am wondering which is the most efficient way to do so.

Bit of background:

1100 sq ft garage attached to house, R50 in attic, R24 walls (2x4 roxul, 2" SM), 3x "R16" doors (1-3/4" thick insulated door, doubt the R16 claimed) and electric heat. Located in Winnipeg where winter temps are down in the -30 C range.

I would like to keep the garage at 10 C and turn it up when I go out to work in it. It houses 2 daily drivers and my race car, so can't avoid the mositure coming in, but want to keep things relatively warm for when I go work in it. The main issue is condensation forming on the garage doors, then dripping down and freezing the door to the floor.

This past year I epoxied the first couple feet of the floor which helped a little with the freezing as the ice seemed to not stick as much as the year before. Still did not solve the problem though. I also had an older dehu running, but it would only pull moisture when temps are above 20 C.

This year looking into the option of either a low temp dehu or putting in an HRV to bring in the dry winter air. Trying to figure out which is the most economical option to go with.

 

[thooks]

What is your budget for this?

 

[BadgerBoilerMN]

HRV is the answer.

 

[buzz]

What is your budget for this?

Didn't really have a budget in mind, not going to spend 5k+, but not looking to have it done for under $100 either.

HRV is the answer.

Any reasoning or just past experience it has always worked best?

 

[Freefall_Doug]

Hrv?

 

[jvitez]

Heat recovery ventilator.

Yes, I think an HRV is your best bet. It's a capital cost vs operating cost decision. We've got 2 HRV's in our R2000 home. They can over-dry the house, so we have the humdistats set to only turn on the HRV's every 20 min. That keeps the inside air at around 30% rel humidity.

It should be a relatively easy install. The intake and discharge vents must go on the same wall. The intake pipe must be insulated or it will drip a ton from condensation. It uses a very small amount of electricity, and only needs a regular 15 amp receptacle. Your garage sounds like the perfect application.

 

[thooks]

Well, if you want to define your budget and possible scope of work a little better, I could possibly help with the decision and equipment selection. $100-$5,000 is a little broad.

Yes, if you are concerned with humidity that much then something along the lines of a system with a sensible heat wheel and refrigeration with reheat is probably your best solution. These are made to control humidity.

 

[buzz]

So lets go with a $1,500 budget. Scope would be to maintain RH levels at 40% or lower at 10 C.

Last year I was maintaining RH levels or 60% at 10C without any equipment. I spent some time yesterday looking at operating costs of Dehu vs HRV when brining down RH from 60% to 40% for my garage. Costs actually came out to a wash, but the HRV did the job twice as fast and was half the cost of the dehu I was comparing to ($700 to $1200). Stepping up to a larger HRV would increase efficiency and cfm and make for even more savings and response time.

I had looked at some dessicant dehus before, but wasn't sure if I wanted to spend 4-5k for the dehu when the HRV may do just as good of job for a fraction the cost. I'll have to crunch some numbers on one of those I guess. Perhaps you can recommend a model to look at?

 

[Freefall_Doug]

How does a HRV work to bring humidity down in the summer?

The winter makes sense, outside air is pretty dry. But when the outside air is hummid as hell in the summer does it actually help?

 

[phbsales]

How does a HRV work to bring humidity down in the summer?

The winter makes sense, outside air is pretty dry. But when the outside air is hummid as hell in the summer does it actually help?

The OP is located in Winnipeg, Manitoba, Canada.

Relative humidity levels for the months of June-August are rarely over 55% which is relatively comfortable, even with ambient temperatures in the mid 80's.

The OP wants more control in the colder months to prevent the condensation from becoming ice.

 

[buzz]

Exactly as said above, only worried about the moisture in the Winter months when it's causing problems with the door operation from condensation and freezing.

 

[CrashTestDummy]

Hrv?

Acronyms are annoying when they're not defined, huh? Google returns this:

http://en.wikipedia.org/wiki/Heart_rate_variability

... among others. Not sure what that has to do with humidity, though.

Gene Beaird,
Pearland, Texas

 

[thooks]

I can't help you. The equipment along I was thinking of is $1500.

 

[jvitez]

Acronyms are annoying when they're not defined, huh? Google returns this:

http://en.wikipedia.org/wiki/Heart_rate_variability

... among others. Not sure what that has to do with humidity, though.

Gene Beaird,
Pearland, Texas

Hmmm, heart rate variability, humidity, sweating.......now I've got it!

Relative humidity: the bead of sweat running down your forehead as you're making love to your brothers wife.

 

[Jackfre]

Give tech service at Tjernlund a call. 800 255-4208. You want to be discussing the AirXchange unit. For your extreme conditions I don't want to hazard a guess. They are excellent people and will take care of you.

Not wanting to guess, but not able to resist, how about an aircurtain at the door. Mars is a manuf of them. If you are able to isolate the air, it may handle the issue for you.

HRV=heat recovery ventilator
ERV=Energy Recovery Ventialtor

It is my understanding that every home in Canada that meets your energy profile has to have one according to the Ventilation Standards. If you have one in the house I would not want to tie the garage into the house system. The Xchanger may be a low cost option for you, with their recommendation.