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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

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    • CommentAuthordickster
    • CommentTime7 days ago
    So when we built our small well insulated house, we went for emergency only LPG underfloor heating via boiler (never used) in case of infirmity or lack of logs , but have used a 5 kW log burner since day 1. That was 10 years ago, now getting older, due to retire, if I go first, how will "her outdoors" manage?

    GSH pumps and the like were, at the time, well beyond our pocket and we didn't have a proper electricity supply, so a no-no.

    Now we are slightly more fluent in cash and have a new electricity supply, but all the heat pump stuff tends to want to heat water up in a tank for the underfloor heating. We have no space for a hot water tank, full stop, but it slowly occurred to me that an air con unit might possibly be used instead for heating in the winter months and doesn't involve hot water tanks.

    I think I'm right in thinking that aircon works the same way as an air source heat pump with a COP of around 3.5. Having studied a few you tubes on same, it looks like it might be a possibility. Our stove is never used in earnest apart from very cold times, just on gentle tick over throughout the day, so nowhere near 5 kW per hour, let's say 3.

    An aircon unit outside with an internal blower the other side of the wall in front room could be just the job.

    Could it?

    Your thoughts please, oh mighty Forum.
    • CommentAuthorowlman
    • CommentTime6 days ago
    The air to air, ( A2A ) air source heat pumps to which you refer are certainly capable of providing a warm interior. Modern digital inverter R32 units can exceed a COP of 3.5 and are extremely quiet in operation both inside and out. they have the added advantage of Summer cooling should you wish.
    The come in single or multiple "splits" i.e. one outdoor condenser unit and several indoor units. Although the indoor units can be individually controlled/output they obviously have to be in the same mode; either heating or cooling.
    Once internal temperature is reached they modulate and just tick over to maintain that level, - very efficient.
    The outdoor unit can be remoted from the indoor and 20 metres plus is not unusual.
    The controls are generally excellent.
    The indoor units come in various configurations not just " the wall blower" to which you refer, - the term tends to put people off BTW.
    Its possible to have ceiling cassettes, ceiling hung, ducted, low level which looks not dissimilar to a storage rad, and the wall units are many and varied.
    They are reliable and generally trouble free.
    They need to be fitted by an "F" gas qualified fitter, not as onerous as you may think.
    • CommentTime6 days ago
    Posted By: dicksterCould it?

    FWIW, I share owlman's views though I haven't seriously thought about getting one installed just yet. So 'yes'.
    • CommentAuthorEd Davies
    • CommentTime6 days ago
    To back up what Owlman says, and as I've mentioned on here before, there are a number of well-insulated small houses in New England (where winters tend to be a bit more fierce than in old England) which use these mini-splits for heating. Though a single unit usually gives enough kW [¹] to heat the house it's common to have one at each end of the house mainly to get the heat evenly spread because, as we've also discussed often, air is fairly poor at moving heat around due to its low volumetric heat capacity. Multiple units also give quicker warm up on the odd occasions that's needed and a degree of redundancy.

    I'm not clear, though, why a suitably modulating ASHP really needs a tank.

    [¹] not “per hour”.
    • CommentAuthordickster
    • CommentTime5 days ago
    Thanks for your confirmations.

    Ed, I try my best and understand what I mean, but I'm so wary of messing up my units in front of audience, I always seem to get it wrong!
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