We recently had an energy audit done by WellHome, a new division of Masco, which is a manufacturer of many types of home/building fixtures and services.
They seemed to do a very thorough job, using high-tech equipment including thermal imaging which showed significant heat infiltration (I live in Austin, TX) in the places I'd expect. Air leakage was 1900CFM50 which they said was somewhat high but not outrageous. After reviewing the printed report I generally agreed with their findings.
The cost of the audit was reasonable ($49) and included no obligation to use them for remediation, although the report included a list of suggested remediation items and none of the prices looked out of line. In fact the cost for replacing the windows with double-pane argon-filled vinly-frame units was quite a bit less than I expected. This was the highest cost item ($9000) but was the lowest suggested priority because according to the report there's more effective "low-hanging fruit". There was no sales pressure at all.
Based on our specific audit, they will "guarantee" a 23% energy savings. Based on a year's worth of utility bills we spend about $1600/year on heating/cooling (is that low?), due to having already picked the really low-hanging fruit (CFLs, conservative thermostat settings), Assuming that they can deliver the savings, it would only amount to about $370/year for a $20000 investment, which clearly makes no sense financially unless it contributes significantly to the equity.
The question: Is this worth considering at all for reasons other than pure enviromental altruism?
Note: I would have used better tags but with less than 150 rep I can't create the tag
"energy-audit".
EDIT: One commenter suggested this question looks like a sales-pitch. On re-reading, I can see that my tone is quite positive, which I guess reflects my feeling about the process. However, I will categorically state that I have no connection to Masco or WellHome (no idea how I can prove it, however 🙂
Best Answer
As you'd need to maintain those $370/year savings for 54 years to gain any return on your investment you do need to consider other factors.
As you point out - you need to work out if it significantly increase the value of your home. Another side to this though is would it make your house significantly easier to sell? In a buyers market if you can offer things that others can't - full insulation, double glazing etc. then you might find a buyer more quickly and one willing to meet your asking price.
Pure environmental altruism is, by definition, impossible to put a figure on. Only you can decide whether $20,000 is an "investment" you want to make.
Finally, something that has just occurred to me. By doing this work you might get ahead of any future legislation requiring you to fit double glazing, extra draught-proofing etc. So if you can afford it now you won't have to make the investment later when you might not be able to afford it or when prices go up because there's more demand. The downside to this is that future laws might be stricter or have tighter limits which would mean that you still need to do some work.