Bests & Worsts Reviews from Amazon

****************************** * Why the Aprilaire 600 * ****************************** Why the Aprilaire 600 instead of the 400? Because the additional water going down the drain over a year would cost a lot less than the extra filters and additional filters and maintenance of the 400. However, water and energy in my area isn't expensive. Therefore, I included my math procedures, which might work for you to work up your own annual cost of operation difference between the 600 and 400 for your specific area. Humidifier Water Costs: Fixed water costs:: - $.26 per day for water maintenance - $.14 per day for sewer maintenance - There a an average of 91 days per quarter - Fixed costs per quarter are:$0.40 * 91 = $36.40 Water cost for humidifier: Winter:Quarter: $1.27 per 100 cubic feet. Sewer is $2.22 per 100 cubic feet $1.27 + $2.22 = $3.49 per 100 cubic feet of water. 1 cubic foot of water costs $0.0349 1 cubic foot = 7.48052 Gallons Water costs $0.004665451064899 per gallon 24*.25 = 6 hours per day furnace runs max. 6 * 30 = 180 hours per month furnace runs max 180 * 3 = 540 hours per quarter furnace runs max 540 x 3 gph = 1,620 gallons per quarter max 1,620 X .001697742937657 per gallon = $7.58 per quarter max. Other quarters: *The charge for water is by usage for all 4 quarters. The sewer for non-winter quarters is based sewer on the winter quarter usage plus 15%, and not associated with water usage for those 3 quarters. The logic is, while people use more sewer those other 3 quarters, they also sprinkle, which doesn't impact the sewer. Thus, any additional water you use in the winter, costs you all year long. - Fraction that is sewer = 0.636103151862464 - Winter sewer portion = 0.636103151862464 x $7.58 = $4.82 - 15% of Sewer portion = $0.723 - Sewer portion added each of non-winter 3 quarters = $5.54 - Total sewer portion added for non-winter quarters = $16.62 - Cost of water per year = $7.58 for the winter quarter + $16.62 for the other 3 quarters combined = $24.20 per year for the 600 (Based on 3 GPH) - Cost of water per year for the 400 = $5.65 per year extra (based on 0.7 gph) - Aprilaire 400 saves $18.55 in water cost per year over Aprilaire 600. (Actual savings would be likely be more because the 600 uses 3 gph, while the 400 only uses what it evaporates, and not more than 0.7 gph,) Summary: - Any way I look at it, the humidifier cannot cost more than $24.20 per year in water, and that would be if it ran 25% of the time though the entire heating season, which is highly unlikely. - The savings of $18.55 of the Aprilaire 400 would likely be eaten up in filters alone, let alone a more complex unit, higher initial cost, and cleaning of slime, sediment, and possible mold. - I understand why they make both models. The numbers would be quite different if I had a well, heated with propane, or lived in an area where water and sewer were expensive. Other: If you run the Aprilaire 600 without furnace heat, Aprilaire recommends running hot water to these units. HVAC experts that have tested the Aprilaire 400 on hot water stated that hot water does not make a measurable difference with the because it is almost impossible to keep it hot by the time it arrives because it uses so little. These costs do not reflect the Aprilaire 600 being connected to hot water. The heat required for vaporization must come from somewhere. In the case of the 600 connected to hot water, it comes from a combination of the furnace and water heater, while on the 400, it must all come from the furnace. ****************************** * How it works * ****************************** How the controller works. - To control the humidity manually, the earlier versions of the controller had a resistor you would put across the ODT (outdoor temperature) sensor terminals in order to fake an outdoor temperature sensor reading of 20F degrees. The newer ones have a switch inside the cover that does the same thing, except it also changes the display by adding an M following the humidity on the display. - The (G) wire coming down from the thermostat is the wire that activates the furnace blower when the Fan switch is turned on, on the thermostat. When installing the humidifier, you remove the (G) wire at the furnace that comes from the thermostat, and using a wire nut, splice into a wire that goes to the (G) terminal on the humidistat. Then run a wire from the humidistat's (G1) terminal back to the furnace's (G) terminal. You have effective put the humidistat in series with the thermostat to control the fan. If the Fan switch is set to On at the thermostat, even with the humidifier in series, it doesn't change the operation of the thermostat's Fan switch. The furnace blower will remain on as long as the switch is set to On, instead of Auto, on the thermostat - The Blower Activation Switch on the Aprilaire 600: a. When the humidistat Blower Activation switch is set to On: 1. It senses to see if the blower is on. If it is on, it relies on the reading of the humidistat, and opens the solenoid valve as needed. 2. If the blower is not on, it turns on the blower for 3 minutes periodically to draw air through the return ducts to measure the humidity. If it finds the humidity below the set point, it opens the solenoid valve and extends the run time of the blower as necessary to return the humidity to the set point. If the furnace blower isn't on, and the thermostat's Fan switch isn't on, where does the humidistat get its power to activate the blower's (G) terminal? The same place the thermostat gets it. There is an (R) wire that goes from the furnace to the humidistat, just like you have with the thermostat. *Before discovering it periodically turned on the blower to sample the air, I was initially concerned that the relative humidity (RH) in the duct would be artificially high because the sensor is 18" upstream from the humidifier and colder, and thus it would never trigger the blower. What I observed from the display is the RH in the duct became much LESS in the duct when the blower is off. I'm not certain why. Humid air is less dense, so perhaps what I'm seeing is least humid air falling down into the ducts. Before the furnace or the humidifier turned on the fan, the RH sometimes indicated 36. After the fan runs for a minute or two, it would read 44, after which I heard the click of the water solenoid, and the blower ran until it returned to the set point of 45. (I have it on manual to force it to regulate to 45, the max) b. When the humidistat Blower Activation switch is set to Off: 1. If the humidity is at or above the setting when there is a call for heat (W), the solenoid valve will not open. If after the blower starts and the return duct air is lower than the set point, the solenoid valve will open. 2. If the sensed humidity is a below the humidity set point, when there is a call for heat (W), the solenoid valve will open whether or not the blower is running yet. However, it requires at least a minute from the time the solenoid valve opens, for water to work its way down to the bottom of the filter, by which time the blower running. Due to the tendency for the duct RH to be lower than the house RH, as mentioned above, this situation frequently occurs. If after the blower starts the control senses additional humidity is not needed, it turns the solenoid valve off as expected, whether or not the heat cycle has finished. - That leaves us with the question as to why they would put the humidistat in series with the thermostat for the blower (G). The humidistat could sense the voltage on (G), just as it does call for heat (W), without putting it in series with the thermostat. There is one difference. With call for heat (W), it only senses. With blower (G) it senses AND switches the blower if necessary. My theory is they discovered a problem in certain situations when paralleling the thermostat's (R) to (G) connection for blower operation. Thus it would sense if the blower is already on, and if not, opens the humidistat's normally-closed blower-in (G) to blower-out (G1) connection, and applies its own hot (R) to the blower-out (G1). - The Aprilaire 600 comes with its own 24V transformer, wired to be powered any time there is power to the HVAC system. The 24V power from the transformer does not connect to any of the wires that interface to the furnace. It's power is isolated for solenoid valve operation only. One output goes directly to the solenoid, while the other goes though the Aprilaire humidistat's two (H) terminals. The separate transformer ensures that there is sufficient capacity to run the solenoid valve, and eliminates any possibility of damage to the HVAC system due to misconfiguration or unintended feedback. - It has a damper valve that has a summer setting (blocks the 6" diameter humidifier supply) and a winter setting (opens the 6" diameter humidifier supply). If you turn the humidistat all the way to the left, it will turn it off. Turning it to the right to 7 is the max. Past the max is a test mode that will run the humidifier for 1 minute, then shut off an flash. - The max RH the control will run the humidifier, according to the docs and experience, is 45%. However, in cold weather, the thermistor will inform the controller of the outside temperature, and reduce the actual humidity set point, even when set at its highest setting. (See the chart in the included manual) If I switched to manual mode, and set it at the max., it would maintain the humidity at 45%. - The only remaining question is if the humidistat that feeds the controller accurate. I don't have a way to test that. I did try making up a wet bulb, but it was 30% different than the humidistat, indicating that the humidistat as understating the humidity, not over stating. Judging by the windows, my wet bulb experiment could not be trusted. Other: - The Model 60 humidistat installation instructions that came with the humidifier, includes a sticker for manual mode that shows dial settings from Off to 45% instead of Off to 7. The sticker markings are linear, so 15% RH is 1/3 of the dial, 30% RH is 2/3rds of the dial, and 45% RH is the max, or number 7 on the dial. I decided to switch mine from automatic mode, which automatically adjusts the humidity level based on the outside temperature, to manual mode, where it simply maintains the humidity at the level you set it. I found that for my situation, that the sensor-driven automatic mode too aggressively reduced the RH. This left the house quite dry at the time I needed it most. I learned that I could get away with a lot more RH without sweating the windows than the automatic mode would allow. In my situation, it needs to get down to 0F before any slight fogging begins to form around the edges of the windows. - A chart in the Aprilaire 600 User's Manual, documents the RH modification effect of the outdoor temperature (ODT) sensor's effect on RH at varying outdoor temperatures. With the Dial on Setting 7, it will hold 45% RH in automatic mode until you go below 20F degrees outside temperature. You can also see by reading down the 20 degree column that the manual mode is based on a 20F degree outside air temperature, which makes the dial linear from 1 - 7. Thus, in Manual Mode, 1 = 15%, 2 = 20%, and every number thereafter up to 7 increases the humidity by 5%. It would actually be more understandable, even in manual mode, to paste this chart next to the control, than try to interpolate the dial stickers that come with it. ****************************** * How I wired it * ****************************** Wiring it for forced air was straightforward. A. The Model 60 humidistat that came with it had the same terminals and color codes as my furnace. Thus, I simply bought some more of the wire that connected to my thermostat, and connected the (R=Red=24v hot from furnace transformer, (C=Black=24v common from furnace transformer), (W=white=call for heat) to the same terminals the thermostat connected to on the furnace. The only exception was, as mentioned earlier, I removed the (G=Green=Activate blower) wire on the furnace that came from the thermostat, wire nutted it to a brown wire to go to the humidistat's (G) terminal, and a green wire from the humidistat's (Gf) back to the furnace. B. Wired the two ODT terminals to the outdoor temperature sensor/thermistor. C. My furnace has a dual-gang box with a switch and fuse in it. The humidifier comes with a 24V transformer that has a threaded post and conduit nut on one end where the white and black 120V wires exit. It was "a piece of cake" to simply knock out a knockout on the box, thread the nut down, and wire nut the black to the black hot wire after the switch, and the white to the white neutral. D. Run one wire from the Aprilaire transformer to the water solenoid. Run the other wire to one of the H terminals on the humidistat, and run another wire from the other H terminal to the water valve. E.G. the only thing that the transformer powers is the water solenoid. One of the 24 volt wires runs through the normally-open relay in the humidistat, which you connect to by using to the two H terminals. This is all pretty clear to me. :D ****************************** * Physical Installation * ****************************** I'm the meticulous, engineering type. Things need to be not only be done right, but also be a work of art when its finished. This is why I do it, rather than hire a professional. Even the wires have labels on them along their length, and use and maintenance procedures are mounted in plastic next the equipment. Hiring it out doesn't save any time for someone like me because I would do half of it over after he leaves anyway. Moreover, I would still need to spend the time learning how it so that I can know if it is effective, and whether I'm using it most effectively. How long does it take to install yourself? By the time I researched the docs on line, decided exactly where I wanted to mount things, and a couple trips to the hardware store, it took over 12 hours to get it perfect. - I used some orange rubber tubing that I had lying around to cover the 6' of 1/4" copper line from the water heater outlet to the humidifier, to keep the water hot. At first I had my doubts, but it ended up insulating so well that the solenoid will burn your hand when the water is running. - The template that comes with it is on the large side, so be careful not to make the hole too big, or you won't have any furnace duct material to screw to because the mounting holes are near the edge. - Make sure you hang the unit perfectly level so that the water drains down through all of the outlets in the top tray. - The wire I used between the furnace and humidistat was 8-conductor thermostat wire from Lowe's, where you can get it cut to length, and the conductors are in the standard colors, which match the letters on the furnace and humidistat. - I used two-conductor door bell wire, red and black, to go between the outdoor sensor and the humidistat. - I also used two-conductor door bell wire to go from the Aprilaire transformer, with the white running to the water valve, and the black running through the H terminals on humidistat to the water valve. - The humidistat I mounted 18" upstream of the humidifier, which is greater than the 6" minimum. - I takes a little thought to come up with a good position for the outside air temperature sensor. You need a spot where it won't be affected by furnace outlets, dryers, snow levels, ice from water dripping, heat from around windows, out of direct sunlight, and out of dead spaces where heated air can build up, so mine is where the prevailing westerlies keep the area swept. - The easiest way to keep things level when drilling and screwing it to the duct is to clamp the humidifier with C clamps around the perimeter of the opening. You can also hold a piece of wood behind where you are drilling so the tin doesn't bend out of the way when you try to drill it. If you strip out a hole, you can easily reach through the opening and use a tinnerman nut on the screw. - I mounted mine to the return duct, but an alternate method is to mount it to the supply duct. You'll either be running a 6" round furnace duct between the unit and supply duct or the return duct. - I needed a tee and some 1/2" clear vinyl tubing to splice into the high efficiency furnace and AC drain. I bought 1/2" vinyl tubing twice. Once off a reel at Lowe's, where it was flat, and told it would get round after I let it set a while, and a second time at the local hardware where they sold round clear vinyl tubing for less money than the Lowe's flattened stuff, and a whole lot closer to home. Hanging the tubing with weights, and using a hair dryer won't make flattened tubing round again I learned, and it will kink in a heartbeat. - At first I had trouble getting the 6" ducting between the humidifier and supply ducting above it, to look good. What I found to be the easiest way was to screw the elbow on the humidifier the way I wanted it to look when it was finished, and screw the elbow into the supply duct the way I wanted it to look when finished, and then play with elbows and straight pieces in between to fill the gap. It turned out drop-dead-perfect looking. - I had some orange silicone rubber tubing that just fit over the 1/4" copper tubing that runs between the hot water line and the solenoid valve, to preserve water temperature. It would have been a lot easier to install had I installed it on the copper tubing before I formed the tubing to follow the route from the hot water pipe to the solenoid valve. ****************************** * Experiences * ****************************** As I mentioned earlier, I switched to manual because my windows don't even sweat at 0F at 45% RH, and I was out to cure nosebleeds. It only took a few hours to get the RH up to 45%. The furnace picked up a slight whistling noise from the air rushing through the humidifier's element, that only I was able to detect. It beats the stars out of the large stand-alone or the rotating drum furnace unit I've had, and there is virtually no noise or maintenance. It's smaller than any of the other units I've owned, and it works better. It is well engineered, very low maintenance, completely automatic, and highly effective. There are very few other things I can say that about.