I found the linked graphic informative. Perhaps a bit over simplified and basic/remedial ... but then maybe that's why I liked it :) .... http://i.bnet.com/blogs/infographic-home-projects-that-pay-you-back.png?tag=content;siu-container

I find it very misleading in terms of the payback periods. For example, how about single digit % savings (or negative if you can no longer use setback) for radiant floor vs their ridiculous claim of 40%.

This info is so bogus. A new high efficiency two stage variable speed furnace is only $1,145? A contractor can't even buy one, let alone install one for this price. Solar water for $2,500? once again maybe 4 times this cost and we are in a good ballpark.

Sky - If I am reading it correctly the number in red appears to be the 'added cost' of purchasing the unit. So they are saying (I think) that the added cost above and beyond what a garden variety furnace would cost - will be 1145. The geo number of 30k actually looks a wee bit high as an added cost. Our unit was 32k in total where as the regular unit was 15k so our 'added cost' for geo was only 17k. Overall I think the graphic is helpful (if a little rough). People need a general idea of what the relative payback times are for energy efficient investments - and this graph is a starting point.

Posted By ANdad on 25 Nov 2011 11:03 AM
Sky - If I am reading it correctly the number in red appears to be the 'added cost' of purchasing the unit. So they are saying (I think) that the added cost above and beyond what a garden variety furnace would cost - will be 1145. The geo number of 30k actually looks a wee bit high as an added cost. Our unit was 32k in total where as the regular unit was 15k so our 'added cost' for geo was only 17k. Overall I think the graphic is helpful (if a little rough). People need a general idea of what the relative payback times are for energy efficient investments - and this graph is a starting point.

That makes a bit more sense, its for added cost during construction. I thought it was a cost to "add" to the home after it was built. But yes even then geo was a bit high and the furnace/solar water heating are still WAY low. The end result is that i think all of them had a less than 10 year payback which is good to see.

There numbers are off to say the least and the fact that there is a small ad in the corner for solar is a bit off-putting.

There are many unstated assumptions behind the numbers that might make them work (eg: going with a condensing boiler and slab radiant floor you can can get 95% true efficiency out it even without setback, compared to an 80% hot furnace and leaky uninsulated ducts that delivers 65-70% true performance), but without real systems, and real number on interest rates, utility rates, and the real-as-used efficiency it's pretty meaningless. Using simple payback rather than net-present value on lifecycle or some standardized time period of substantial length is also not cutting it.

I doubt anybody is going to read that goofy graphic as gospel, and to the extent that it makes people actually run the numbers I suppose that's a good thing. On a major rehab/remodel or new construction going hi-her efficiency isn't always more expensive, eg. the upcharge on a condensing gas furnace can be even cost-negative on day-1 if it means you then don't need to build or re-line a chimney. And going "right sized" rather than (the ridiculous & rampant) oversizing of heating & cooling equipment results in smaller-cheaper units that last longer, run more efficiently, providing greater comfort.