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Green Building Bible, Fourth Edition
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    • CommentAuthordelprado
    • CommentTimeFeb 2nd 2018
     
    But what do I do about heating downstairs? It seems even passiv haus have heating?
    • CommentAuthorTimSmall
    • CommentTimeFeb 2nd 2018
     
    I ended up with UFH on the ground floor (since those floors were be replaced anyway, and marginal cost wasn't much), radiators in the bedrooms, and UFH in the new bathrooms. The extra UFH in the bathrooms is nice, but was a faff. Glad I did the GF tho'.

    All runs at the same temp, so no extra pump and mixing valve.
  1.  
    Posted By: delpradoBut what do I do about heating downstairs? It seems even passiv haus have heating?


    Our house is heated with three electric towel rails.
    • CommentAuthortony
    • CommentTimeFeb 3rd 2018
     
    Mine is people, and incidental gains, when I go out we have a table lamp in the lounge with a 60W lightbulb to replace my contribution. The inter seasonal store helps by reducing ground heat losses.
  2.  
    Posted By: tonyMine is people, and incidental gains, when I go out we have a table lamp in the lounge with a 60W lightbulb to replace my contribution. The inter seasonal store helps by reducing ground heat losses.


    Isn't it more comfortable to have some heat in the bathrooms and also a source of heat for the MHRV extract?
    • CommentAuthortony
    • CommentTimeFeb 3rd 2018
     
    Nice steady temperatures work well, basement 19.5, lounge 21, bedrooms 18.8 never feels cold.
  3.  
    Posted By: me on a previous page.
    We just calculated about the same heat demand as delprado. I think 2 people and a lightbulb will provide about that much heat, (switch to LEDs in the summer) but just to be sure I bought a plugin electric panel heater (a good one, £100+).

    For low cost 'insurance' heating, I'm going with electric wall panel heaters. These arrived this week, look great but not tried yet: https://www.amazon.co.uk/ADAX-NEO-Electric-Panel-Heater/dp/B008Y02ISK .


    Just moved back in after refurbishing/insulating the upstairs, and we're glad of the electric panel heaters. They are high quality, don't smell of burnt dust, and are nearly silent (not totally). Very much cheaper to install than central heating. Each heater can be programmed with its own setback cycle, though the timer is a fiddle to set up.

    They seem to be on more than was expected when I calculated the heat losses, not quantified yet but could be that airtightness is not as good as expected.
    •  
      CommentAuthordjh
    • CommentTimeFeb 4th 2018
     
    How easy is it to change the element(s) in that heater?
    • CommentAuthortony
    • CommentTimeFeb 4th 2018 edited
     
    I have just had a similar arguement on a referbishment project. The supervisor wanted the main contractor to change from gas heating to direct electric panel heating. I was a consultant on the project and was asked by the main contractor for my opinion.

    I said to the client and main contractor that although the proposed new heating design was 100% efficient that it would cost three times as much to run as gas condensing boiler wet system would. If they really must use electric then please fit A2A heat pumps 350% efficient but little bit of noise to contend with. Gas system would need biannual servicing.

    As a result of my intervention the client instructed the wet gas system with very high tech controls as they were in for the long run.

    Future proofing will be wet A2W linked to the wet rads.
  4.  
    Tony, that's what I have done for the existing wet heating through most of the downstairs of the house, been on A2W ASHP for several years as I posted elsewhere.

    After refurbishing the upstairs with decent insulation, the calculated heat demand for the upstairs averages 200W of which most should be solar gain, so it is not worthwhile to extend the wet heating to the upstairs, would not pay back the plumber. I considered heating it only with people and lights like you do, but we added small electric panels as insurance and are glad we did.

    DJH, looks like the elements could be replaced with a screwdriver in a few minutes, they come with big fins built on to them, but the heater is guaranteed and cheap so probably would just replace the whole thing if it failed.
    • CommentAuthordelprado
    • CommentTimeFeb 27th 2018
     
    Is using an electric post heater an option in a house with a properly designed heating system downstairs, with the post heater designed to boost only the bedrooms?
    •  
      CommentAuthordjh
    • CommentTimeFeb 28th 2018
     
    Posted By: delpradoIs using an electric post heater an option in a house with a properly designed heating system downstairs, with the post heater designed to boost only the bedrooms?

    With a suitably complicated MVHR setup, and a well-enough insulated house that a post heater is a feasible heating system it could be made to work, but using individual panel heaters would be cheaper and more flexible.
    • CommentAuthorgravelld
    • CommentTimeFeb 28th 2018
     
    Posted By: tonyI said to the client and main contractor that although the proposed new heating design was 100% efficient that it would cost three times as much to run as gas condensing boiler wet system would.
    Three times of how much though? If the demand is low enough, the savings in opex might not outweigh the capex of just getting some oil filled rads from Argos.
  5.  
    <blockquote><cite>Posted By: gravelld</cite>Three times of how much though? If the demand is low enough, the savings in opex might not outweigh the capex of just getting some oil filled rads from Argos.</blockquote>

    Our gas bill was £418 last year (heating and hot water). So £800 a year extra to go fully electric. Even if the boiler only lasts 10 years there's a fair saving.
    • CommentAuthorgravelld
    • CommentTimeFeb 28th 2018
     
    Yeah but if your demand was lower... I was thinking of more like half that. Then consider the cost of the wet system and boiler being installed and servicing.

    On the other hand, if the demand is low, there are fewer rads to put in. Also it will probably hurt sale-ability iin the UK to not have a wet system.

    Furthermore you could consider a wet system in the same way of network cabling - future proofing by installing it, even if it isn't required immediately, so you can fall back on it. Better to do it at build time?
  6.  
    I reckon about 40% of our demand is hot water (mostly for 2 people) so half is about as low as you can go (unless you're adding in solar water)
    • CommentAuthorgravelld
    • CommentTimeFeb 28th 2018
     
    Yep - thanks.
    • CommentAuthordelprado
    • CommentTimeFeb 28th 2018
     
    So my new calcs say 310w heat loss for larger front bedrooms, and 210w for the small back bedrooms. I think I'm gonna go for it and eschew heating
    • CommentAuthortony
    • CommentTimeFeb 28th 2018
     
    Try reducing the design temperature up there by one degree
    • CommentAuthordelprado
    • CommentTimeFeb 28th 2018
     
    at the moment its for a temp difference of 21 degrees - even now in bournemouth its only minus 3. So are you saying do it to 20 degrees instead? KIts interesting how little difference it makes. 2.7 watts for a 11sqm wall!
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