PDA

View Full Version : Humidifier Math



frankt
11-27-2007, 07:53 PM
My old Aprilaire 550 has seen better days and it seems to make more sense to replace it vs repair. It has never really quite kept up even though it ran 24/7 with continuous fan. Probably because of the 60 recessed can lights in the house.

I did a little math comparing water use and included the increased sewer charges for running the 400, 500, and 600 Aprilaire's. My sewer charges are based on how much water is used during the winter quarter, so flow-through designs cost me extra for sewer all four quarters.

Based on the math and past billings my 550 cost me about $161 a year in water ($61) and sewer ($100) charges. Not to mention the cost to heat 140+ Gallons per day. OUCH!

The 600 would use about $81 a year. It flows 3 GPH vs 6 GPH for the 500/550.

The 400 would use about $19 if it used all of it's 17 Gallon a day output capacity, and no hot water.

The 400 will require more maint. because of needing an extra pad per year, and added complexity, but from a water use standpoint is the clear winner.

Flushing from 12-24,000 gallons of water down the drain over 6 months just to keep the pad clean seems like a real waste.

Dave-B
11-27-2007, 08:18 PM
A steam humidifier will use less water and in my opinion humidfy better.

lackster
11-27-2007, 08:58 PM
Frank-

Search this site for "TrueSTEAM". Thats the latest design from Honeywell that fixes several problems suffered by other steam units, and the largest problem with most pad-style evaporative units, a waste of precious water. I write this from Atlanta, where we are in the midst of our worst drought in memory.

The Trusteam unit is due to ship in December, and may be worth waiting for.

frankt
11-27-2007, 10:25 PM
I looked at the Truesteam HARD. Looks like a nice unit. But WOW to get 12 Gallons a day output would require over $90 a month in electric, at my $.09 per KWH. That 1440 Watt heating element would really make the meter spin.

My old Aprilaire 550 wouldn't keep up, but wasn't that far off. It's hard to say just exactly how much the 550 really puts out (claimed 12 GPD max), but the specs say the 400 and 600 put out 50% more (17 GPD max). That should be more than enough.

mark beiser
11-28-2007, 12:11 AM
It has never really quite kept up even though it ran 24/7 with continuous fan. Probably because of the 60 recessed can lights in the house.

If you fix the actual problem, not only will you have better humidity control, but you will have energy savings that will last for the life of the home.
Recessed can lights are easy to fix, as are most other major sources of house leakage.
Finding the leaks can be a bit tricky, but a blower door infiltration test would reveal them.

Tighten up the house and you may not need much humidification at all.

Why not fix the problem instead of just appling a bigger bandaid?

lackster
11-28-2007, 06:13 AM
I looked at the Truesteam HARD. Looks like a nice unit. But WOW to get 12 Gallons a day output would require over $90 a month in electric, at my $.09 per KWH. That 1440 Watt heating element would really make the meter spin.

My old Aprilaire 550 wouldn't keep up, but wasn't that far off. It's hard to say just exactly how much the 550 really puts out (claimed 12 GPD max), but the specs say the 400 and 600 put out 50% more (17 GPD max). That should be more than enough.

Don't forget to allow for the possible savings from lowering the temperature in your home due to humidified air feeling warmer. Of course, as Mark points out, we should all strive to tighten the home envelope.

browntigerus
11-28-2007, 07:47 AM
Based on the math and past billings my 550 cost me about $161 a year in water ($61) and sewer ($100) charges. Not to mention the cost to heat 140+ Gallons per day. OUCH!

Flushing from 12-24,000 gallons of water down the drain over 6 months just to keep the pad clean seems like a real waste.

Mine is nowhere near your numbers... How did you get those.... I have avg 100 gal/day usage with humidifier running. 3600 sq ft house with 1700 sq ft basement... I don't know about sewer charges. Most homes I have seen dump water into same drain as condensate => sump pit => $0 sewer bill = good for environment as it doesn't have to be treated vs waste water.

frankt
11-28-2007, 10:23 AM
Browntigerus

Wow....less than 100 gal day including the Humidifier....

Do you live alone? Our lowest use quarter ever was about 190 gallons a day and that was WITHOUT the humidifier. Our 190 galons a day is even on the low side of what the utility company said was "avarage" use for my size family.

Here's the math...Aprilaire 550 uses 6 GPH X 24 Hrs X 90 Days = 12960 Gal.

12960 Gal. / 748 gal (1 water billing unit) = 17.3 units X $1.80 =$31.19 X 2 Quarters = $62.38

12960 Gal. / 748 Gal. (1 Sewer billing unit) = 17.3 units X $1.45 = $25.13
X 4 Quarters = $100.49 My sewer gets billed all year on my WINTER quarter use.

So over $160. per year

If your humidifier dumps into a floor drain it's going into the sewer or septic.
If it dumps into a sump pit that does to daylight that would be a different thing. If I did that mine would freeze as it left the house.

cn
11-28-2007, 10:50 AM
My 2 cents:

1. My Aprilaire 550 is wired in such a way that it runs only when the furnace is ON.
So when furnace is OFF it does not waste water.

2. My RH is the house is about 30-35%.
In the morning when waking up, you should see a very small rim of water below the window and that is normal (per my builder).

3. To humidify the bedroom, use a portable steam humidifier ($12 at Wlgreen's) when sleeping at night.

It works like a charm.

Constant excessive humidity will damage the window and wood work.

Like others have said, do an infiltration test to see where the air leak is, then tighten up the house. You will see a dramatic difference.

frankt
11-28-2007, 12:42 PM
Part of my problem is just sheer volume. I'm conditioning almost 57,000 Cu Ft. with several 16 and 12 ft patio doors plus 60+ recessed lights.

I have had about 45 of the lights sealed up so far and the rest will be finished shortly, so that alone should help considerably.

I am well aware of the effects of "excess" humidity and don't want to get to those levels.

An evaporitive humidifier should work quite well with the Rheem MOD I just had installed. Since it runs almost 100% of the time I don't want water running through the humidifier all the time. It seems like the Aprilaire 400 is the answer.

Shophound
11-28-2007, 12:47 PM
If you fix the actual problem, not only will you have better humidity control, but you will have energy savings that will last for the life of the home.
Recessed can lights are easy to fix, as are most other major sources of house leakage.
Finding the leaks can be a bit tricky, but a blower door infiltration test would reveal them.

Tighten up the house and you may not need much humidification at all.

Why not fix the problem instead of just appling a bigger bandaid?

Same thing I thought when I read he had sixty can lights throughout the house. Sixty! Imagine if each one leaked at a paltry 1 cfm per can, that would be sixty cfm overall...equivalent to turning on a small fart fan in a bathroom and leaving it run 24/7.

Yet another example of throwing more energy at a problem that can be mitigated by reducing the demand for energy...seal and insulate! Passive solutions should always be maximized before looking at active solutions.

MoveOver
11-28-2007, 01:46 PM
Mine is nowhere near your numbers... How did you get those.... I have avg 100 gal/day usage with humidifier running. 3600 sq ft house with 1700 sq ft basement... I don't know about sewer charges. Most homes I have seen dump water into same drain as condensate => sump pit => $0 sewer bill = good for environment as it doesn't have to be treated vs waste water.

Most water co's charge for sewage eventough it might not end up in there. So even if you dump it in the sump pump you still get charged sewage rates.The sewage rate is based on you water usage, that's why some people have a second water meter for outdoor water usage.

cn
11-28-2007, 03:21 PM
Buy a 12-Gallon Humidifier and there is virtually no waste of water at all.
http://www.laskoproducts.com/humidifiers/model_1130-40.html

The water stays in the large 12-G container with a drum inside.

I think this is your best solution.

frankt
11-28-2007, 03:33 PM
If you look at the cube I'm Conditioning it's almost 6000 SqFt with 10 Ft ceilings. I said my 12 Gal a day bypass humidifier "almost" keeps up. So I don't think I'm quite as "leaky" as you might think.

20 Years ago there was no such thing as
"Airtite Cans". ;)

mark beiser
11-28-2007, 07:53 PM
20 Years ago there was no such thing as
"Airtite Cans". ;)

Easy enough to fix.;)
http://www.ccl-light.com/docs/indoor/recessed/6in120vstandardtrims/c3atw/index.html

stvc
11-28-2007, 08:31 PM
I have an Aprilair 600. It uses 0 water and costs 0 on my sewage bill.
It has been turned off for over 2 years, 41% RH in my house right now.
I fixed the air leakage.:)

frankt
11-28-2007, 10:41 PM
Mark

Have you purchased from CCL before? They seem to have a P### Poor reputation.

mark beiser
11-29-2007, 12:21 AM
Mark

Have you purchased from CCL before? They seem to have a P### Poor reputation.

Yes, we have purchased several cases of the air tight trims, and installed them in customers homes , no problems yet. Seems to be a good quality product.
A few of our customers have purchased them on our recommendation, some people like to pay for the testing, then DIY some of the easy sealing work. No complaints about this product yet.

They also have some that are $1.99 each that look ok and are actually easier to install, but I don't recommend them because they can't be removed without destroying the spring tabs that hold them in the fixture.

There is a slightly nicer looking air tight trim replacement available from another source, but they are in the neighborhood of $15-$17 each, and are not enough nicer looking to warrant triple the cost.

frankt
11-29-2007, 09:35 AM
There is a slightly nicer looking air tight trim replacement available from another source, but they are in the neighborhood of $15-$17 each, and are not enough nicer looking to warrant triple the cost.

I assume your talking about Halo's air tite trims here.

cn
11-29-2007, 10:14 AM
I don't know how old your ceiling can is but the funny thing about Ceiling Can is: We want lighting but we do NOT want to lose heat (it is contradictory)!

- When the Celing light is on: heat loss is from the heat produced by the bulb itself and leakage of home HVAC air around the trim/can.
- When the Celing light is off: heat loss is from leakage of home HVAC air around the trim/can.

- IC (Insulated Ceiling) Cans are basically the same as Non-IC can but "double encapsulated", so basically 2 layers of metal to avoid excessive heat to the insulation (? fire hazard etc. although fiberglass is not combustible).

- The IC Can allows insulation to come into contact with the Can itself without risk of overheat.

http://www.thisoldhouse.com/toh/article/0,,212235,00.html
Picture 2 shows you the IC can should have a little space around it.
(Do this only for can in the second floor attic, for cans between 1st and 2nd floor, the heat is still in the enclosed bldg envelope so no heat loss here).

My 2 cents:
1. For IC cans on the second floor (above them is the attic). You migfht want to build a little "cave" around them and place insulation above it.
2. Using aluminum tape (used for sealing HVAC duct), seal the holes in the cans. Use less wattage here 35-40W bulbs so less heat, less loss, but a bit less light output.
3. Seal around the can and ceiling drywall.
4. Use trim with rubber seal around the edges.

5. Check your windows seals too. If imposssible to change the seal then use some kind of insulation kit (looks like saran wrap and seal the windows in the winter)

This is the same others have said: tighten up your home.