I was recently asked a question that,
at least on the surface, seemed like a straightforward one…"There
are several ways to save energy, but often times the payback on the energy
saving device is close to 27 years because I already live a very energy
efficient lifestyle. So the question becomes, "How does a person who is
already saving energy make the improvements to their home that will yield a
return on investment (ROI) and because they are the right thing to do.
I started to think of Energy Star appliances, a
high efficiency water heater and other improvements that one can do after they have
the basics covered. Then I thought
I’d better ask them what they had already done to consider themselves energy efficient.
I got the typical answer of “we bought a 15 SEER HVAC system, added some attic
insulation, put in some CFL bulbs, you know the typical stuff.” There were a
few more things that were added to the list during the conversation, but I
never heard them mention any air sealing work that amounted to more than “spray
foaming the pipes in the kitchen cabinet”. So I asked a few more questions.
Me-“What
was your duct leakage number when the HVAC was installed?”
Her-“I
don’t remember there being one, but the unit is 15 SEER!”
Me-“Did
you air seal anything before putting the attic insulation in?”
Her-”
We didn’t need to. The contractor told me that the insulation would seal up the
holes and keep the cool air in.”
Me-“Have
you noticed much of a drop in your power bill?”
Her-“Not
yet, but this winter was pretty mild and we just installed the AC.”
This was a conversation with someone that
considered themself energy efficient.
I have to say that their intentions were good, and I certainly don’t want to
make light of that, but they missed it by a mile. Step one in any energy
conservation program with your home is air sealing…keeping the conditioned air
in and the unconditioned air out. You must have a clearly defined thermal
barrier before you attempt any energy saving measures. Well you don’t have to, but without it you will never
reach your maximum saving potential.
I meet people every day that assume blown or batt
insulation will keep the conditioned air inside their home; it will not, it
simply slows down the heat transfer
between conditioned and unconditioned space. Spray foam insulation will slow the heat transfer and air
will not penetrate it, but it is expensive and if you already have some attic
insulation it may not be worth spending the extra money. Sealing attic
penetrations under the insulation before adding the new might be the simplest
and cheapest approach. The payback will certainly be much quicker and it is
something to consider doing yourself.
The 15 SEER HVAC was not a bad idea…if it needed
replacing anyway. If it was still
in working order you could probably have saved as much money by duct sealing as
you did by replacing the unit. And if the ducts weren’t sealed properly on the
new one, you won’t save a dime! The difference in Kilowatt hours (KWH) used by
a 13 SEER and a 15 SEER is about 15%. If you used 10,000KWH to air condition
your home the savings would only be $165.00 annually! (10,000X.15X.11kwh=$165) You
could probably save that much in six months from duct sealing alone and I don’t
imagine that the new unit will last long enough to ever pay you back!
There are a lot of companies out there that
advertise products that will save you 40%-50% on your power bill. I don’t think any of us really believe this, and I
think companies like this do more harm than they do good. You can make
statistics say anything you want! I’ve monitored several hundred homes over the
last two years and have documented some great energy savings, but a practical
approach that is low in cost and done in steps will be the quickest path to
putting more money in your pocket after the bills are paid.
