Dehumidifier - Aprilaire, GeneralAire, Ultra-Aire, Honeywell.

[508gm1]

Attached are pictures of the unit installed. Still working great!

[Mderosa3]

Sorry to bring up old thread but wondering how the Honeywell is holding up? What are you controlling it with?

[508gm1]

The original failed late last year - slow Freon leak. Replaced under warranty which was a bit of a pain but the supplier was great & helped me out. The replacement is made overseas. I was hoping the thing would have lasted about 5 years. We'll see how this one holds up. Next one will be an Aprilaire [should have taken Mr. Teddybear's advise!]

[ThomOen]

Not sure which one is the best. They all work ok in the places i have had them installed.

[sheedyhvac]

I had a commercial customer go through probably 30 aprilaires. Ive put in around 60 quest units which is santa fe and ultra aire rebranded in commercial applications . These things are running 247 and rarely have issues. Dropped one from 15 ft on to concrete once when my lift failed and it ran just fine. I only had a qc issue with their split system dehumidifiers but ill still always recommend their products.

[teddy bear]

The Ultra-Aire/Santa Fe/Quest all made by Therma-Stor in Madison WI. They are the originator of the high efficiency durable dehumidifier 1992.
Their premium units remove 9 pints KWH +40% more than most.
6 year warranty on current equipment.
Thanks for the support.
Regards Teddy Bear

[CoolAir Inc.]

DR65 is right option but why the contractors are saying that higher capacity will be ideal? If you do not mind higher energy cost then go for it. But higher capacity dehumidifier does not make sense. Please do not only rely on dehumidifier and keep your HVAC filters clean to keep the air quality fresh.

[opey456]

teddy what is the preferred method to bring in fresh air with the 65 Honeywell?

[teddy bear]

teddy what is the preferred method to bring in fresh air with the 65 Honeywell?

Install is important. If you want 60-70cfm of fresh air, a 6" insulated duct from the fresh air inlet grill with a screen to the dehumidifier. The small whole house units have an 8" duct inlet. A tee is needed to combine the 6" to the 8" return from the open part of the home. Avoid connecting the dehumidifier return to the a/c return. If the fresh air duct is more than 20 ft long, upsize the 6" to an 8" to avoid excessive air flow restriction. Some add an adjusting damper for fine tuning and also a electric damper for switching on/off.
Fresh air should be on during occupancy especially during mild weather/windows closed. During the coldest winter weather when the home is too dry stop or slow fresh air.
Welcome aboard fresh air and humidity control.. Keep us posted on how it works out.
Regards Teddy Bear

One more important point is that your a/c is setup with correct amount of air flow through the cooling coil. A good a/c setup with maintain <50%RH when the a/c is operating +50% of the time without an assistance from the dehumidifier. If not, adjust the air flow through the cooling coil to remove enough moisture. A good tech will do this for you.

[opey456]

Yes we usually setup our units for proper airflow to maintain good humidity setting. But with everyone foaming houses now we are starting to see more of a need for dehumidifiers, and wanting to bring in fresh air also. Just was curious your preferred method. Some install manuals can be pretty vague as to what works best.

[pentop]

Avoid connecting the dehumidifier return to the a/c return. .

Can someone elaborate on why this is a bad idea? I totally understand the point about dumping the dehu supply into the AC supply downstream of the wet AC coil. What I can't wrap my head around is why I wouldn't want to pull from the AC return and save cutting another hole into my walls?

[teddy bear]

Can someone elaborate on why this is a bad idea? I totally understand the point about dumping the dehu supply into the AC supply downstream of the wet AC coil. What I can't wrap my head around is why I wouldn't want to pull from the AC return and save cutting another hole into my walls?

Ideally, best to have the dehu be able to circulate dry air throughout the home with out operating the central a/c blower. These blowers use as much electricity as the dehumidifier. Also the dehu must suck air from the negative pressure of the return and supply into the positive pressure of the supply. The dehumidifiers blowers can avoid the negative pressure of the return duct when it is connected to the open part of the home.
So two benefits, avoid the energy to operate the a/c blower when dehumidifying only and increased increased air capacity operating the dehumidifier only. Also the amount of fresh air through the dehumidifier will be more constant if sucked from outside via the dehumidifier return if only shared with a return from the house only verses having the fresh air connected to the dehu-a/c return.

If you need more info on this point come back for more info.

Regards Teddy Bear

[pentop]

If you need more info on this point come back for more info.
Regards Teddy Bear

I will take you up on your offer. Thanks for your patience with me.

I guess my first misunderstanding is that I thought in a standard install that the dehu was locked out when the HVAC is running. What you said makes sense that by attaching to the return of a running HVAC that the dehu is pulling return air from a low pressure situation and essentially pulling from a vacuum. The dehu fan works harder to push less airflow.

Let’s take the situation when the HVAC is not running at all. The dehu return is attached to the HVAC return and the dehu supply is attached to the HVAC supply. (Plus fresh air intake from outdoors). Am I correct that in this situation that there is no performance difference between a dedicated return for the dehu and the shared return from HVAC/dehu?

I’m on this point because I finally found a local contractor to install an UA 120H for me. He wants to install connected to the HVAC return, run the HVAC blower full time, add supplementary outside air, dump into HVAC supply. I’d like to avoid running the HVAC blower all of the time. My problem is that I have an open floor plan and the only place where a dehu return MIGHT work is on the other side of the stairs opposite the HVAC return. To me that makes sense, but every contractor I talked to seems to not want to do it. I’m not sure if it is because it is more work for them because there isn’t as much room under the stairs as I think for a 2nd return.

The reality is that my HVAC only runs a few hours per day, even in the high summer. If I can’t get my dedicated dehu return, can I get good performance for both fresh air and dehumidification with a shared return? I realize that performance will drop during HVAC run time, but how much am I really suboptimizing if I need to go this route?

[teddy bear]

I will take you up on your offer. Thanks for your patience with me.

I guess my first misunderstanding is that I thought in a standard install that the dehu was locked out when the HVAC is running. What you said makes sense that by attaching to the return of a running HVAC that the dehu is pulling return air from a low pressure situation and essentially pulling from a vacuum. The dehu fan works harder to push less airflow.

The DEH3000 controller allows blocking the dehu from running while a/c is running Less air flow and the a/c blower uses as much electricity as the dehu.


Let’s take the situation when the HVAC is not running at all. The dehu return is attached to the HVAC return and the dehu supply is attached to the HVAC supply. (Plus fresh air intake from outdoors). Am I correct that in this situation that there is no performance difference between a dedicated return for the dehu and the shared return from HVAC/dehu?
Not so. The a/c fan must run to prevent the dry air from the dehu from flowing back through the a/c coil-air handler to the dehu return unless a backdraft damper blocks the recirculation dry through the coil/air handler. I assume that the a/c blower is not a VS blower?
I’m on this point because I finally found a local contractor to install an UA 120H for me. He wants to install connected to the HVAC return, run the HVAC blower full time, add supplementary outside air, dump into HVAC supply. I’d like to avoid running the HVAC blower all of the time. not good if standard a/c blowe My problem is that I have an open floor plan and the only place where a dehu return MIGHT work is on the other side of the stairs opposite the HVAC return. To me that makes sense, but every contractor I talked to seems to not want to do it. I’m not sure if it is because it is more work for them because there isn’t as much room under the stairs as I think for a 2nd return.

The reality is that my HVAC only runs a few hours per day, even in the high summer. If I can’t get my dedicated dehu return, can I get good performance for both fresh air and dehumidification with a shared return? I realize that performance will drop during HVAC run time, but how much am I really suboptimizing if I need to go this route?

So much more cost effective to avoid operating the a/c fan while dehumidifying. The dehu will suck in the fresh air, blend it with house air, filter the mix air, dehumidify when needed, and circulate the air throughout the house via the a/c ducts. If the a/c blower is VS we may have a few more options.

Regards Teddy Bear

[pentop]

So much more cost effective to avoid operating the a/c fan while dehumidifying. The dehu will suck in the fresh air, blend it with house air, filter the mix air, dehumidify when needed, and circulate the air throughout the house via the a/c ducts. If the a/c blower is VS we may have a few more options.

Regards Teddy Bear

I checked the specs of my HVAC unit and yes, it does have a variable speed blower.

Based on your explanations, I'm going to push harder about adding the dedicated return, but please go ahead and let me know the options that open up with a VS blower.

[teddy bear]

With a VS blower operating on very low speed, the amount of electricity is reduced to less than 100 watts with 200 cfm of air flow. So a/c blower "on" would use 2-3 kwh per day, <$.30 per day in most areas. Still prefer the original concept of dehu returning from open part of the and outside fresh air, but if extremely difficult, we have an option.

Regards Teddy Bear

[pentop]

Many thanks Teddy Bear for the answers to my questions! The unit is on backorder until December sometime, so I won't have an update until then. You've given me a lot to think about.

[pentop]

An update. I FINALLY found a contractor who would do it right. There was a mention on another thread of HVAC 2.0 and when I did a search on that term in my town, I found exactly the type of contractor I was looking for.

Even though I am just adding a whole house dehumidifier, he insisted that all of his installs include a blower door test and Manual J. (No complaints here!). We ended up on an UltraAire 98H, 70 cfm fresh air, AND he was the only one to agree to add a dedicated return under my stairs, connecting to the supply. All of this controlled with a Honeywell IAQ thermostat.

They are in the middle of installing it now. The added price over my previous quotes is worth it. They're being incredibly clean with strong attention to detail. I'm glad I waited for the right contractor, but gawsh was it incredibly hard to find someone to do it right.

[teddy bear]

Keep us posted as the season goes on.
Thanks for the support with the Ultra-Aire 98H.

Regards Teddy Bear

[dbjeng]

With a VS blower operating on very low speed, the amount of electricity is reduced to less than 100 watts with 200 cfm of air flow. So a/c blower "on" would use 2-3 kwh per day, <$.30 per day in most areas. Still prefer the original concept of dehu returning from open part of the and outside fresh air, but if extremely difficult, we have an option.

Regards Teddy Bear

I am thinking about installing an Aprilaire E080 or E100 (the E100 is now cheaper than the E080 on Amazon). Their install guide recommends the suction and the discharge of the dehu in the suction side. I've been reading your info (great stuff - thanks) and wanted your thoughts on my install.

My house is about 2200 ft2 w/ a 3.5ton h.p. - sized so the heat pump will produce most of the heating w/o having to pull strip very often. I have a VS air handler. I checked today w/ a clamp on ammeter and my fan in cooling pulls 5.39A and in fan only mode pulls 0.78A. Assuming a 1.0 p.f., the fan only mode is pulling about 187W (vs. 1293W in cooling) and fan only is pulling about 14.4% of the cooling fan energy.

Mine system is in Alabama, a 14 y.o. house that is very well insulated w/ low energy bills. I will be doing the install myself (I used to be in the HVAC industry and can do the install). Mine is a slab house and the unit is in the attic, as is the duct work. The attic floor is covered in plywood in the area of the return duct and the air handler. I really do not want to pull up that plywood and cut in an additional suction in the ceiling. My air handler suction is at floor level and the filters are located there, so no need to go in the hot attic to clean the filters. There is a large return and a smaller one that comes from the MBR - it's filter is at floor level also.

The easiest install would be to sit the dehu on top of the air handler and duct return-return and supply-supply. I like that idea BUT I presume it would only work w/ the A/C running so there would be no backflow thru the air handler? Thoughts? Also, I could have the dehu return pull from the box that comes up through the ceiling from the filters (at the floor level in the living area) which is about 10' total duct run and 2 turns from the air handler rather than directly from the air handler return input box if that would add enough distance to keep the dehu from short circuiting back through the air handler. What do you think?

The next easiest would be to build a stand and do the whole dehu in the return line between the 2 boxes mentioned above like Aprilaire's suggested install. I guess I could not run the system fan in this mode and save the fan energy (losing the wet a/c coil sometimes, etc.). On days like we have in April, May and Oct., the A/C hardly runs at all so this might be a good bet. Your thoughts?

The E080 is rated 5.1A (612W), the E100 is 6.9A (828W) assuming a 1.0p.f. for a total, with the system fan running of 799W or 1015W.

Also, the install of an outside air duct would be a bit of a job and I was thinking about not doing that now (or ever?).

Your guidance, directions and/or corrections on these choices would be highly appreciated.

Thanks,
David