[vba616]

It doesn't seem like the chart of costs includes the effect of summer A/C.

And the chart that is shown peaks in winter a couple months early.

Overall, it seems to significantly underestimate my energy costs.

The conclusion is also confusing: it says I would save $89/year or $24K in 15 years. Huh?

$89/year doesn't seem like enough to justify any investment, and $24K is about $1600/year or ~95% of my current costs, which seems too high to believe.

[bake]

This is really good feedback, thank you -- the "$24k" number is something we're going back to the drawing board on, we're reaching too much there. That number includes the capital costs of replacing and installing equipment (a single heat pump vs. both a furnace and an A/C unit, for example, plus rebates), and it's best case for heat pumps vs. worst case for legacy equipment. So, I think you're right, it just doesn't line up sensibly with the really concrete annual energy savings numbers.

On winter peaks, I'll have to look into what you're seeing -- we pull weather data from the nearest ASOS station to your zip code and have done a fair bit of validation on that data, but it could be a number of things. If you're interested, you could send the inputs you're using to [e-mail] and I'll do a little digging?

[bake]

FYI, we just updated that section of the results to hopefully be clearer and, when it comes to the total lifetime savings including equipment costs, a bit more conservative.