Read this before you buy a radiant barrier.

P2000, Energy Shield… there will probably be other brand names out there if there aren’t more already.  These are the green product equivalent of snake oil as one recent customer has found out.

First, what is it?  Or should I say, how is it being marketed by the manufacturer?  It is being advertised as a “REFLECTIVE INSULATION made up of 5 protective layers. These 5 layers reflect heat and send it back to the heat source, so your home stays WARMER in the winter and COOLER in the summer.”  It has a very authoritative illustration showing that there is an “insulative core” sandwiched between “99.9% Aluminum”.  The headline reads “Do you want to save 35% or more on your heating and cooling costs?”

A customer visited this week for a home energy audit paid $4000 for this “system” to be installed in her attic.  She said that her house is still freezing:

A closer look revealed it as two layers of a radiant barrier with a thin layer of fiberglass insulation in between.  This has a thermal value of less than 1.  For the record in our climate, a homeowner should have an R50 in the attic.  A radiant barrier has some use in southern hot and sunny climates.  Installed correctly – on the underside of the roof-deck – it can reduce cooling loads by a significant margin (but certainly not 35%).  In Kansas City which is a heating dominated climate (in spite of our hot summers we still heat our homes four times longer than we cool them), a radiant barrier will not have a fast payback.

Just in case I haven’t been clear:  this homeowner paid $4000 to lay a large piece of aluminum foil in her attic.

If it sounds too good to be true, it probably is.  The company that is selling this product is reportedly closing several sales around the Kansas City metropolitan area.

So, be forewarned and beware – this product is bunk.  Do you want to save up to 35% on your energy bills?  Well, insulate, air seal and upgrade your furnace.  Change your light bulbs and appliances to high-efficiency models.  That will put you on the path to potentially 20-30% usage reduction on your utility bills.

 

Houses that make you go “Hmmmm..”

Recently I was called for an audit because the master bedroom was “freezing cold” as the homeowners classified it.  They wanted a prescription for more comfort – a very reasonable request.

The room in question was on the second floor of a story and a half house built originally in the 1940′s.  It sat over the house’s office on the first floor and at first investigation appeared to be a head-scratcher.  The construction was unlike anything I had seen to this point.  There was the office that sat on a concrete slab which was built over an original fully dug basement masonry foundation wall.  This is unusual, because one doesn’t ever see a concrete slab over a basement; one usually sees a concrete slab on the ground, and anything over a basement would be a wooden floor joists holding wooden sub-floor and flooring over that.  Secondly, the office walls were insulated, but the master bedroom walls were not.  What did we have going on here?

Most likely, the office was an outdoor room like a screened in porch or storage facility.  The master bedroom was most likely part of the original house cantilevered over this space.  At some point a previous owner had either decided they wanted more conditioned space and enclosed the porch for the office, or perhaps it was something they did out of desperation due to the freezing master bedroom above the porch.

Unfortunately building an insulated room below the cantilevered master bedroom didn’t resolve the comfort issue.  Why?  The reason appears to be the band joist (the joist that encloses the floor joists between the first and second floor) was over a thick load bearing header that wasn’t air sealed or insulated.  Besides the fact that the walls of the original home weren’t well insulated (or insulated at all), the master bedroom sits over an empty pocket of air in between floor joists that have cold air blowing through them in the winter.  This makes it way up into the second floor, dilutes the warm conditioned air from the ductwork and forces the warmer air to exit up through the roof of the house that needed better insulation and air sealing as well in the attic.

What’s a homeowner to do?  This isn’t an easy fix, unfortunately.  Getting behind a band joist to seal and insulate is tough.  The ceiling in the office could be retrofitted with packed cellulose by drilling and blowing into each floor joist cavity from the office  – packed cellulose would go a long way to stopping the air flow through the band joist.  Then retroactively insulating the  master bedroom walls wouldn’t be throwing good money after bad.

Why the room above this room is so cold:

More on this house and what the homeowners decided to do at some future date…

 

A fun year so far in energy inspections…

Attics are revealing places.  Since I have been balancing on ceiling joists for the better part of three years now, it’s safe to say that I probably still have many more insights to gain in these dark other worldly spider havens (luckily… not an arachnophobe!)

For example, in my most recent foray into a large flat space above a story and a half home, I found an open wall cavity that led half way down the wall bordering a dropped soffit in the master bathroom.  The wall in question in the home housed the thermostat.  The result was that the thermostat hung on a hollow wall with baking attic air filling the empty cavity that was open at the top in the attic.  The thermostat thus registered the temperature about 4 degrees hotter than was the case throughout the remainder of the home.  Hence the air conditioner ran and ran and ran during these hot summer months in the Kansas City area.

Why would a home be built with hollow wall cavities open to the attic?  Poor oversight in the construction process to begin with.  This house was built long before “building” and “science” went together.  Perhaps the builders felt that their “state of the art” batt insulation that they added at the time made it irrelevant.  Fast forward several decades later to present day, however, and you have an energy auditor that is able to see  – past the 3 inches of old deteriorating insulation that is hardly making any thermal impact  – into something that almost resembles the rabbit hole that Alice fell into.  Here is what it looks like from an infrared camera’s point of view inside the home at the wall in question:

Attics are interesting places