If you pull air from the living space with the humidex that air is going to be replaced. Where is the makeup air going to come from? If your hvac system doesnt have a dedicated fresh air vent the air will likely come from all the cracks in your house like thru the walls, windows. attic, etc. Wcwn though its probably happening now it will be increased with a humidex. That kind of air can be unfiltered and dirty, and also contain more moisture and heat in the summer leading to lower quality indoor air and higher AC costs. I looked at humidex for my place and think the concept is interesting, but just couldnt get my mind around the problems of that low quality makeup air.

I purchased a Humidex about 4 years ago , have a very large basement .In process of finishing off basement.We purchased unit to remove odors and moisture control and it works,uses very little power to run, NO difference in utilites . I have a very tight home , but not too tight..if you install one make sure they put a wind cover on it, ONLY DRAWBACK PRICEY. I feel unit has paid for itself in energy savings.

My experience with Humidex is like doberman_2007. I have a humidex in my current home's basement. It was pricey but it helped take the odor and Radon out of the basement. The unit doesn't use much electricity either.

My new house has a crawlspace and I don't want to add vent holes to supply conditioned air to that space. I also don't want to pay the high cost of electricity.

I have been reading these HVAC threads for a while and so much good information is shared here. I am hoping that some of the professionals would weigh in on cost benefits.

I looked at a bunch of different dehumidifiers and checked their eficiency ratings. The most efficient ones are 5 times the cost of the standard ones but only save about $35 to $40 per year. The payback period is about 12 years.

Thanks for your input - doberman and doobzz

So let me see if I've got this right. This thing will draw out my
conditioned air with 40 or 50 percent humidity and draw in 70 to
100 percent humid air from leaky doors, windows, and attic hatches
all the while back drafting my furnace and waterheater!
Sign ME up!

"indoor air is more toxic than outside air"

That very much depend on where you live. Here the air is full of
mold spores, pollen, dust and high humidity. Having allergies
I much prefer my indoor air to what's outside.
And before someone mentions why I'm running my furnace
and AC at the same time...in this part of Texas it necessary many
days during Spring and Fall when it's freezing at night and 80+ during the day.

It worked for me and I am sold on it ,I have noticed our allergy problems are significantly less with the HUMIDEX.
I guess it is what you like , and I like fresh air . so be it. If you have a good filter system on your furnace and it is working for you fine..

I'm not so sure that the backdraft is going to draw in the exhaust fumes from the water heater or the furnace. The motor is small and pulls about 200 CFM. I also found that the basement's musty odor has virtually dissapeared.

While I am sold on the Humidex for the current application, I can see there is a controversy between this product and the standard dehumidifier. I don't know if it is the right thing for the new house - yet!

It sure seems that this topic has no "best" answer. I am however interested in the exchange of opinions and ideas.

Thanks to all...

I have to admit I'm mostly playing Devil's advocate. Because I've
already replaced my window and doors, had the duct work sealed
and weatherstripped the hatch and sealed all electrical and plumbing
penetrations.
Also the furnace and water heater both have air supplies now as well,
but what I said about humidity, and allergens still begs the question of
how this thing draws in MORE humid air and dehumidifies your home?

saltcedar

I certainly agree that there are lots of qustions about the Humidex's operations. The "theory" is that it that it works like and ERV ... that is it relies on "dry" air from another place in the house to dilute and absorb moisture in the area that is being conditioned. So perhaps the humid air being drawn in is not as humid as the air in the space where the unit is situated. Will it draw in allergents, probably. Is that a good thing, not likely since my wife has allergies.

That brings me back to the humidifier. I can get just a run of the mill unit for about 200 bucks that sucks electricity at a high rate. Or I can buy an energy star unit that costs 5 times that and saves me about $35 bucks a year (payback is about 12 years). Or even better than that, I can get a bigger unit which costs $1800 and does the same job as the $1000 unit but the payback is 15 years. Some choice...

The link below is for the Therma-Stor units I have been advised to get.

Regards,

Here is a link that might be useful: Therna-Stor Dehumidifiers

look for it in the site I suggested, maybe here you can find the one you need. Good luck! :)

Here is a link that might be useful: Crawl space dehumidifier