Kill-A-Watt question

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  • TelcoTelco Solar Expert Posts: 201 ✭✭✭✭✭
    Re: Kill-A-Watt question

    I want to see the water bed go away also because the wife likes it a lot warmer and softer than I do. Now I have a new reason to want it gone, danged thing almost uses as much juice as the old, non-efficient fridge does.
  • BB.BB. Super Moderators, Administrators Posts: 32,612 admin
    Re: Kill-A-Watt question

    Be really careful about the Select Comfort beds... There have been quite a few complaints about mold.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • TelcoTelco Solar Expert Posts: 201 ✭✭✭✭✭
    Re: Kill-A-Watt question

    Yipes, thanks for the warning. My wife has allergy-induced asthma so even the risk of a moldy mattress rules this out. This sucks, because the wife doesn't want a regular mattress at all. Looks like I'm gonna be stuck with a water bed then. Oh well, one thing we are going to do then is get a new liner with the baffles and back support because I'm this |--| close to moving to the couch.

    Looks like if I ever get a place up I'll be looking at the radiant heating loops under the mattress then. Either that or no heater at all, with a nice thick piece of foam between us and the water.
  • BB.BB. Super Moderators, Administrators Posts: 32,612 admin
    Re: Kill-A-Watt question

    I would not recommend the "no heater" water bed either... Decades ago, my Father disconnect the heaters to save energy in a couple of our water beds and put insulating foam on top.

    Other than the bed being really cold for the first few minutes--they where OK to sleep on. However, when I took them apart and replaced with regular beds a few years later--the bed liners were soaked with water. I don't remember any mold--but that was 30 years ago and I really don't remember the details.

    In the end, both a cold water bed, or the "air mattress" type beds all of a fundamental problem of a cool air/water chamber that condenses water from warm bodies, and being impermeable plastics, they don't breath/dissipate the moisture.

    Insulating the base of your water bed and using a heavy comforter (at least during the day) should cut down the heat loss quite a bit.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • TelcoTelco Solar Expert Posts: 201 ✭✭✭✭✭
    Re: Kill-A-Watt question

    Bummer, would have been nice.

    Since we can't do the air mattress we are going to get a better liner, what sort of insulation would you suggest putting under it? Something like blueboard styrofoam for house walls? It'll have to be pretty thin to fit in there, and be able to handle having the heater element on it. We already have three quilts on it for the wife's comfort so that part's covered. Told the wife we were also going to be putting a 2 inch foam mattress topper on when we do this too, so that'll help.
  • mike95490mike95490 Solar Expert Posts: 9,572 ✭✭✭✭✭
    Re: Kill-A-Watt question

    waterbed heater: use the smallest wattage unit you can live with. Test your current one, if it's on 20% of the time, go to half wattage, and it should be on 40% of the time, that lowers the power density (if you are running off inverters)

    insulation:
    I had first used styrofoam, and it quickly mashed down to paper thin. Useless. You need some rigid construction foam
    http://www.builditsolar.com/Projects/SpaceHeating/SolarShed/Tank/Construction.htm
    3/4 down to INSULATION.
    at least 1" of polyisocyanurate foam, foil on at least 1 side. (brown tan color) It should resist mashing like stryofoam doesnt. I placed a sheet of 1/8" aluminum under my heater, that extended a couple inches past the heater, to spread the heat out a little better, and keep the foam cooler. Just polish edges well to keep from cutting anything. I did not insulate the sides back then, but I would now, rigid foam between liner and baggie.

    water bag:
    seriously look into a waveless mattress. I had the type with 2" of foam, floating inside the bag. Placing a blanket of foam outside the bag ruins the floating effect of the waterbed. I used a GI wool blanket over the bag, and then my sheets, and used a down quilt over the whole works. place nothing over the down quilt, if it's compressed, it's not insulating anymore . I know of no other insulation better than goose down (other than vacuum or aerogel)
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  • BB.BB. Super Moderators, Administrators Posts: 32,612 admin
    Re: Kill-A-Watt question

    I was thinking of insulation under the structure of the water bed so that the weight of the water won't collapse the insulating material.

    You could try the aluminized "bubble wrap" under the bed (and probably even around the edges of the bed (but I don't worry as much about the edges as the total square footage is pretty small compared to the top and bottom)

    Changing to a smaller heater will reduce the "peak loads" on your inverter but probably won't reduce your total kWhrs per day by much (unless the heater itself is getting very warm and losing heat through the bottom of the bed).

    Other than using "alternative heat sources" (such as piping the condenser lines from your fridge to your water bed)--insulation is about the only way I can see to cut your overall power usage (without getting rid of the water bed).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • backroadbackroad Solar Expert Posts: 185 ✭✭
    Re: Kill-A-Watt question

    If I remember correctly, out aquarium heater uses about 40 watts continually?....?.....I believe these electric heaters are a close relative to a dead short.
  • BB.BB. Super Moderators, Administrators Posts: 32,612 admin
    Re: Kill-A-Watt question

    Telco,

    I should mention that I have no experience with the Select Comfort beds... I found the mold complaints by chance while looking up folk's experiences with them (thought about getting one at one time)...

    Backroad,

    "Dead Shorts" are all relative... 40 watts on a 1 volt battery would require 40 amps of current or 0.025 Ohms of resistance.

    40 Watts at 120 VAC would be 0.33 amps or 360 Ohms.

    Both have the same power rating but a ratio of 14,400 to 1 between relative resistances.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Kill-A-Watt question

    bill, i think you just confused him. let me try.
    in the case of a short your breaker would've popped so it isn't a dead short. in fact what is a dead short anyway? i figure it has to do with somebody dying, but people are not a short either as the body too has a high resistance. i guess that to mean enough conductivity to cause death, but that depends on the current and how it passes through the body. nobody died not even the fish, right?:confused:
  • TelcoTelco Solar Expert Posts: 201 ✭✭✭✭✭
    Re: Kill-A-Watt question

    NP. I'll get a piece of this insulation and lay it inside the cover, and I've got aluminum laying around that I can put the heater on. I agree that heater size isn't going to affect the 24hr usage, just the usage drawn on a minute by minute basis. It'll draw more per minute, but fewer minutes per day. The mattress we have now is a full wave, ie a bag for holding water, and the next one we are going to try will be a level 3 with back support.

    On the select comfort, the possibility of mold being blown around the room any time someone lays on the bed is enough to kill the whole idea.
  • backroadbackroad Solar Expert Posts: 185 ✭✭
    Re: Kill-A-Watt question

    dount ya thunk my reference to a heater as a dead short, might have been a bit of a strech, as in humor???LOL.....
    I'll go away now and find another forum to abuse me...:):):);)
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Kill-A-Watt question

    we all had a stab at some humor then as i too tried it. the clue was here, "bill, i think you just confused him. let me try." meaning let me try to confuse you. maybe i'll update that to read concircuit breaker you.:confused::cry::roll:
  • nigtomdawnigtomdaw Solar Expert Posts: 705 ✭✭
    Re: Kill-A-Watt question

    I need to lie down in a dark room with a 6ft Swedish Lady :p
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Kill-A-Watt question

    sounds good, but be sure you see what she looks like in the daylight first as she could be shim or just plain blah.:blush: ok time for me to behave or get smacked by other half.:cry:
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