heat and insulation

Discussion in 'Designing, building, making and powering your life' started by pebble, Jun 18, 2009.

  1. pebble

    pebble Junior Member

    Apr 24, 2007
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    inland Otago, NZ
    Inland maritime/hot/dry/frosty
    I need to get my head around how heat and insulation work. I'm getting a housetruck built and doing some design work at the moment. A few questions:

    If you stop heat getting out does that always mean you are stopping it getting in too eg if I get double glazed windows will there be less passive solar heating?

    How does passive solar work in terms of cloudy days in winter? I can see how it works really well on sunny days, but if you have lots of glass for instance don't you lose excessive amounts of heat on non-sunny days?

    Do people generally insulate non-glass really well and use glass for passive capture, is that how it works?

    Is silver paper a useful underfloor insulation? Does it have to have light to work or can it be in the dark (I've been told to seal the bottom of the truck after all the insulation is in)?

    Any good resources on low end heat/insul/solar design?

    I understand how strawbale and earth houses keep a very even temperature over the whole year and need less heating. Can anyone see how I could approach that kind of efficiency with a housetruck? I'm probably lining with timber (cedar) and/or coloursteel, with wool insul. And obviously the walls can't be too thick. But still there must ways. eg can I make the shadey side of the house thicker or more solid?

  2. lyn

    lyn New Member

    Jun 19, 2009
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    Re: heat and insulation

    Hi, not sure about window size and insulation in a housetruck (guessing windows would have to be quite small and laminated for safety reasons?).
    However, I do have experience with double-glazing! Our double-glazed windows do act like a heater on winter mornings. Standard house with aluminium improved windows, a large 1.8 x 2.0m window with standard clear glass 5mm-8mm space-5mm facing ENE is sometimes slightly too warm to sit in front of on a sunny winter morning (even when only 7-10° outside). Technically solar heat gain is meant to be lower from double-glazed windows, but I think it all has to do with the sun angle, glass thickness and spacing. With large double-glazed ENE and NNW windows our living area easily heats to 22-24°C on a sunny day.

    Double-glazing will still lose heat on non-sunny days, and at night (just slightly slower than single glazing). Best thing are thick curtains with pelmets to keep the heat in at these times.

    Remember that on the flip side double-glazing will also cook your interior in summer and must be shaded on hot days. Easy to do on a standard house with eaves, not so easy on a truck (although if your home is mobile I guess you could turn it around to face the sun in winter and the shade in summer!)

    Don't forget to insulate internal walls if you have any.

    Good luck!

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