Comments on: Off-Grid Living

By: Tom Levy

Tom Levy — Mon, 14 Dec 2009 18:56:58 +0000

Mauro –

The selling feature, off grid or not, is that it is easier to conserve energy than it is to make energy. There are a myriad of programs out there that will enable you to examine performance improvements of energy efficiency measures, determining cost-benefit ratio of energy efficiency measures etc. Several come to mind: RETScreen and HOT 2000 are common programs. There is also “HOMER” from NREL, which is a great program, but focuses more on renewable energy production.

Most standard HVAC firms should be able to analyze heating and cooling loads. Typically all you really need to know are U values for windows, square footage of glazing vs. floor area, and wall/roof insulation values. Typically this information is then used to size HVAC equipment. If you want to talk more, go to my facebook page and add me as a friend, then we can chat via email (or contact David and get my contact details from him). FYI – I will be on “Connect with Mark Kelley” tonight, somewhere b/w seven and nine at night, EST. Cheers! Tom

By: Mauro Pacitto

Mauro Pacitto — Tue, 20 Oct 2009 02:52:52 +0000

Hello Tom,

I saw the Living Lightly movie tonight and was impressed with what you have done. I am an architectural designer and try to encourage clients to add some energy saving features to their homes. I was wondering, when you designed your house for passive solar gain, if you found any useful formulas or simulation programs. Stuff like % of windows, vs area and thermal mass calculations.

Great work,

Thanks,

Mauro Pacitto

By: Cathy Patterson

Cathy Patterson — Tue, 28 Apr 2009 12:17:48 +0000

Thank you for this post, it was really interesting to read. I love to read and write about this kind of living.

By: Thomas

Thomas — Fri, 21 Nov 2008 14:18:42 +0000

Terry -

Good catch! That is a typo, and winter should be changed to Summer. It is easier to heat a house off the grid than it is to cool a house – why? Air Conditioning vs. Woodstove….an air conditioner consumes 30A on 220 V power, a wood stove consumes no energy. Design your house for cooling, and not heating. Fortunately designing for cooling will ensure an efficient home to heat as well, so it all works out!

Cheers –
Tom

By: Terry Newcombe

Terry Newcombe — Thu, 20 Nov 2008 15:44:44 +0000

Thank you, Thomas, for writing that detailed but succinct explanation of your philosophy and system. I was only puzzled by one line: “We used light colours for finishing the exterior walls and roof so we can reflect sunlight in the winter.” Do you mean “summer”, to prevent overheating? I hear that this is more common than dark colours in order to improve heat absorption in the winter, but I’m not sure why it’s better (maybe summer cooling is more expensive than winter heating?). I’ve been reading about passive solar heating and I understand that concrete floors or tiles receiving the south winter sun work best when dark coloured to maximize solar gain.
Thanks again,
Terry.